diff --git a/changelog.d/boarder-lodger-rent.added.md b/changelog.d/boarder-lodger-rent.added.md
new file mode 100644
index 000000000..10b057539
--- /dev/null
+++ b/changelog.d/boarder-lodger-rent.added.md
@@ -0,0 +1 @@
+Model rent from boarders, lodgers and sub-tenants for the householder: rent-a-room relief in income tax, the £20 and board-and-lodging disregards in the legacy means tests (not Universal Credit), and no non-dependant deductions for people who pay the householder rent.
diff --git a/policyengine_uk/data/uprating_indices.yaml b/policyengine_uk/data/uprating_indices.yaml
index fe3072c0c..2019fa3a5 100644
--- a/policyengine_uk/data/uprating_indices.yaml
+++ b/policyengine_uk/data/uprating_indices.yaml
@@ -103,6 +103,8 @@ gov.economic_assumptions.yoy_growth.obr.per_capita.gdp:
 - private_pension_wealth
 - private_transfer_income
 - property_income
+- rent_paid_as_boarder
+- rent_paid_as_lodger
 - savings
 - savings_interest_income
 - sublet_income
diff --git a/policyengine_uk/parameters/gov/dwp/legacy_means_tests/board_and_lodging_disregard/amount.yaml b/policyengine_uk/parameters/gov/dwp/legacy_means_tests/board_and_lodging_disregard/amount.yaml
new file mode 100644
index 000000000..4d5600638
--- /dev/null
+++ b/policyengine_uk/parameters/gov/dwp/legacy_means_tests/board_and_lodging_disregard/amount.yaml
@@ -0,0 +1,33 @@
+description: >
+  Weekly amount disregarded in full from the payments a claimant receives for
+  board and lodging accommodation provided in their home, for each person
+  provided with it. Payments above this amount are disregarded in part (see the
+  excess rate). Income Support, income-based Jobseeker's Allowance,
+  income-related Employment and Support Allowance, Housing Benefit, Pension
+  Credit and the council tax reduction schemes use it.
+metadata:
+  label: Legacy benefits board and lodging disregard
+  period: week
+  unit: currency-GBP
+  reference:
+    - title: The Income Support (General) Regulations 1987 Schedule 9 para. 20
+      href: https://www.legislation.gov.uk/uksi/1987/1967/schedule/9/paragraph/20
+    - title: The Income Support (General) Amendment Regulations 1990 regs. 1 and 22(c)
+      href: https://www.legislation.gov.uk/uksi/1990/547/made
+    - title: The Income-related Benefits Schemes (Miscellaneous Amendments) Regulations 1994 regs. 1(1)(b), 1(3) and 9(4)
+      href: https://www.legislation.gov.uk/uksi/1994/527/made
+    - title: The Housing Benefit Regulations 2006 Schedule 5 para. 42
+      href: https://www.legislation.gov.uk/uksi/2006/213/schedule/5/paragraph/42
+    - title: The Housing Benefit (Persons who have attained the qualifying age for state pension credit) Regulations 2006 Schedule 5 para. 9
+      href: https://www.legislation.gov.uk/uksi/2006/214/schedule/5/paragraph/9
+    - title: The State Pension Credit Regulations 2002 Schedule IV para. 8
+      href: https://www.legislation.gov.uk/uksi/2002/1792/schedule/IV/paragraph/8
+    - title: The Council Tax Reduction Schemes (Prescribed Requirements) (England) Regulations 2012 Schedule 5 para. 9
+      href: https://www.legislation.gov.uk/uksi/2012/2885/schedule/5/paragraph/9
+values:
+  # Income Support Schedule 9 para. 20 has disregarded £20 and half the
+  # excess since 9 April 1990 (SI 1990/547), restated in its current words
+  # from 11 April 1994 (SI 1994/527). As made it disregarded £35 of the weekly
+  # charge where the claimant was employed in providing board and lodging;
+  # that rule is not modelled.
+  1990-04-09: 20
diff --git a/policyengine_uk/parameters/gov/dwp/legacy_means_tests/board_and_lodging_disregard/excess_rate.yaml b/policyengine_uk/parameters/gov/dwp/legacy_means_tests/board_and_lodging_disregard/excess_rate.yaml
new file mode 100644
index 000000000..28765f4b5
--- /dev/null
+++ b/policyengine_uk/parameters/gov/dwp/legacy_means_tests/board_and_lodging_disregard/excess_rate.yaml
@@ -0,0 +1,22 @@
+description: >
+  Share of the weekly board and lodging payments above the board and lodging
+  disregard amount that is also disregarded, for each person provided with
+  board and lodging accommodation in the claimant's home.
+metadata:
+  label: Legacy benefits board and lodging disregard rate on the excess
+  unit: /1
+  reference:
+    - title: The Income Support (General) Regulations 1987 Schedule 9 para. 20(b)
+      href: https://www.legislation.gov.uk/uksi/1987/1967/schedule/9/paragraph/20
+    - title: The Income Support (General) Amendment Regulations 1990 reg. 22(c)
+      href: https://www.legislation.gov.uk/uksi/1990/547/made
+    - title: The Housing Benefit Regulations 2006 Schedule 5 para. 42(1)(b)
+      href: https://www.legislation.gov.uk/uksi/2006/213/schedule/5/paragraph/42
+    - title: The Housing Benefit (Persons who have attained the qualifying age for state pension credit) Regulations 2006 Schedule 5 para. 9(b)
+      href: https://www.legislation.gov.uk/uksi/2006/214/schedule/5/paragraph/9
+    - title: The State Pension Credit Regulations 2002 Schedule IV para. 8(1)(b)
+      href: https://www.legislation.gov.uk/uksi/2002/1792/schedule/IV/paragraph/8
+    - title: The Council Tax Reduction Schemes (Prescribed Requirements) (England) Regulations 2012 Schedule 5 para. 9(b)
+      href: https://www.legislation.gov.uk/uksi/2012/2885/schedule/5/paragraph/9
+values:
+  1990-04-09: 0.5
diff --git a/policyengine_uk/parameters/gov/hmrc/income_tax/rent_a_room/basic_amount.yaml b/policyengine_uk/parameters/gov/hmrc/income_tax/rent_a_room/basic_amount.yaml
new file mode 100644
index 000000000..887f41902
--- /dev/null
+++ b/policyengine_uk/parameters/gov/hmrc/income_tax/rent_a_room/basic_amount.yaml
@@ -0,0 +1,26 @@
+description: Basic amount of rent-a-room receipts an individual can receive in a tax year free of income tax. An individual who does not meet the exclusive receipts condition, because someone else also receives rent from the residence, has half this amount.
+values:
+  1992-04-06:
+    value: 3_250
+    reference:
+      - title: Finance (No. 2) Act 1992 Sch. 10 paras. 6 and 13
+        href: https://www.legislation.gov.uk/ukpga/1992/48/schedule/10/enacted
+  1997-04-06:
+    value: 4_250
+    reference:
+      - title: The Income Tax (Furnished Accommodation) (Basic Amount) Order 1996 art. 2
+        href: https://www.legislation.gov.uk/uksi/1996/2953/made
+      - title: Income Tax (Trading and Other Income) Act 2005 s. 789(4) (as enacted)
+        href: https://www.legislation.gov.uk/ukpga/2005/5/section/789/enacted
+  2016-04-06:
+    value: 7_500
+    reference:
+      - title: The Income Tax (Limit for Rent-a-Room Relief) Order 2015 arts. 1(2) and 2
+        href: https://www.legislation.gov.uk/uksi/2015/1539/made
+metadata:
+  label: Rent-a-room relief basic amount
+  period: year
+  unit: currency-GBP
+  reference:
+    - title: Income Tax (Trading and Other Income) Act 2005 s. 789
+      href: https://www.legislation.gov.uk/ukpga/2005/5/section/789
diff --git a/policyengine_uk/tests/policy/baseline/gov/dwp/legacy_means_tests/boarders_and_lodgers.yaml b/policyengine_uk/tests/policy/baseline/gov/dwp/legacy_means_tests/boarders_and_lodgers.yaml
new file mode 100644
index 000000000..3b917fd6b
--- /dev/null
+++ b/policyengine_uk/tests/policy/baseline/gov/dwp/legacy_means_tests/boarders_and_lodgers.yaml
@@ -0,0 +1,384 @@
+# Rent from boarders and lodgers living in the household, in the legacy means
+# tests (legacy_benefits_home_letting_income, counted by Income Support,
+# Housing Benefit, Pension Credit and council tax reduction).
+#
+# Board and lodging, per boarder: the first £20 a week is disregarded and half
+# the excess (IS Sch 9 para 20; HB Sch 5 para 42; HB (SPC) Sch 5 para 9; SPC Sch
+# IV para 8; CTR (England) Sch 5 para 9). Lodging only: £20 a week is
+# disregarded. Claimants over the qualifying age for State Pension Credit
+# disregard it from "the amount paid by that person" (HB (SPC) Sch 5 para 10;
+# SPC Sch IV para 9); working-age claimants from the aggregate paid by "that
+# person or a member of his family" (HB Sch 5 para 22; IS Sch 9 para 19), £4
+# before 7 April 2008. Universal Credit does not count this rent (UC Regs 2013
+# reg 66(1); ADM H5112).
+
+- name: Pension-age householder, one lodger paying £100 a week
+  # (100 - 20) x 52 = 4,160.
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      householder:
+        age: 70
+        is_household_head: true
+      lodger:
+        age: 30
+        is_household_head: false
+        rent_paid_as_lodger: 5_200
+    benunits:
+      householder_unit:
+        members: [householder]
+      lodger_unit:
+        members: [lodger]
+    households:
+      household:
+        members: [householder, lodger]
+  output:
+    legacy_benefits_home_letting_income: [4_160, 0]
+
+- name: One boarder paying £100 a week
+  # 0.5 x (100 - 20) x 52 = 2,080.
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      householder:
+        age: 70
+        is_household_head: true
+      boarder:
+        age: 30
+        is_household_head: false
+        rent_paid_as_boarder: 5_200
+    benunits:
+      householder_unit:
+        members: [householder]
+      boarder_unit:
+        members: [boarder]
+    households:
+      household:
+        members: [householder, boarder]
+  output:
+    legacy_benefits_home_letting_income: [2_080, 0]
+
+- name: A boarder paying £15 a week is disregarded in full
+  # 780 / 52 = 15 < 20.
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      householder:
+        age: 45
+        is_household_head: true
+      boarder:
+        age: 30
+        is_household_head: false
+        rent_paid_as_boarder: 780
+    benunits:
+      householder_unit:
+        members: [householder]
+      boarder_unit:
+        members: [boarder]
+    households:
+      household:
+        members: [householder, boarder]
+  output:
+    legacy_benefits_home_letting_income: [0, 0]
+
+- name: Pension-age householder, a lodger couple each paying £60 a week
+  # Per person: (60 - 20) + (60 - 20) = 80 a week; x 52 = 4,160.
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      householder:
+        age: 70
+        is_household_head: true
+      lodger_1:
+        age: 30
+        is_household_head: false
+        rent_paid_as_lodger: 3_120
+      lodger_2:
+        age: 32
+        is_household_head: false
+        rent_paid_as_lodger: 3_120
+    benunits:
+      householder_unit:
+        members: [householder]
+      lodger_couple:
+        members: [lodger_1, lodger_2]
+    households:
+      household:
+        members: [householder, lodger_1, lodger_2]
+  output:
+    legacy_benefits_home_letting_income: [4_160, 0]
+
+- name: Working-age householder, the same lodger couple
+  # Aggregate for the family: 120 - 20 = 100 a week; x 52 = 5,200.
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      householder:
+        age: 45
+        is_household_head: true
+      lodger_1:
+        age: 30
+        is_household_head: false
+        rent_paid_as_lodger: 3_120
+      lodger_2:
+        age: 32
+        is_household_head: false
+        rent_paid_as_lodger: 3_120
+    benunits:
+      householder_unit:
+        members: [householder]
+      lodger_couple:
+        members: [lodger_1, lodger_2]
+    households:
+      household:
+        members: [householder, lodger_1, lodger_2]
+  output:
+    legacy_benefits_home_letting_income: [5_200, 0]
+
+- name: A boarder and a lodger, each paying £100 a week
+  # Boarder 0.5 x 80 = 40; lodger 80; 120 a week; x 52 = 6,240.
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      householder:
+        age: 70
+        is_household_head: true
+      boarder:
+        age: 30
+        is_household_head: false
+        rent_paid_as_boarder: 5_200
+      lodger:
+        age: 40
+        is_household_head: false
+        rent_paid_as_lodger: 5_200
+    benunits:
+      householder_unit:
+        members: [householder]
+      boarder_unit:
+        members: [boarder]
+      lodger_unit:
+        members: [lodger]
+    households:
+      household:
+        members: [householder, boarder, lodger]
+  output:
+    legacy_benefits_home_letting_income: [6_240, 0, 0]
+
+- name: Working-age lodger disregard was £4 before April 2008
+  # 2007-08: lodger (100 - 4) x 52 = 4,992; a boarder at £100 would give
+  # 0.5 x 80 x 52 = 2,080, here alongside: total 7,072.
+  period: 2007
+  absolute_error_margin: 0.01
+  input:
+    people:
+      householder:
+        age: 45
+        is_household_head: true
+      lodger:
+        age: 30
+        is_household_head: false
+        rent_paid_as_lodger: 5_200
+      boarder:
+        age: 31
+        is_household_head: false
+        rent_paid_as_boarder: 5_200
+    benunits:
+      householder_unit:
+        members: [householder]
+      lodger_unit:
+        members: [lodger]
+      boarder_unit:
+        members: [boarder]
+    households:
+      household:
+        members: [householder, lodger, boarder]
+  output:
+    legacy_benefits_home_letting_income: [7_072, 0, 0]
+
+- name: Universal Credit does not count rent from a lodger
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      householder:
+        age: 35
+        is_household_head: true
+      lodger:
+        age: 30
+        is_household_head: false
+        rent_paid_as_lodger: 5_200
+    benunits:
+      householder_unit:
+        members: [householder]
+      lodger_unit:
+        members: [lodger]
+    households:
+      household:
+        members: [householder, lodger]
+  output:
+    uc_unearned_income: [0, 0]
+
+- name: Rent between members of a household is not household income
+  # The lodger's earnings are the household's only market income.
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      householder:
+        age: 35
+        is_household_head: true
+      lodger:
+        age: 30
+        is_household_head: false
+        employment_income: 20_000
+        rent_paid_as_lodger: 5_200
+    benunits:
+      householder_unit:
+        members: [householder]
+      lodger_unit:
+        members: [lodger]
+    households:
+      household:
+        members: [householder, lodger]
+  output:
+    household_market_income: 20_000
+
+- name: Tax on counted rent from a lodger is deducted in the legacy means tests
+  # 2026-27. Private pension 15,000: (15,000 - 12,570) x 20% = 486. Lodger rent
+  # 10,400 is rent-a-room receipts; 10,400 - 7,500 = 2,900 taxable, x 20% =
+  # 580. Income tax 1,066, all of it on income the means tests count (IS Sch 9
+  # para 1; HB Sch 5 para 1; SPC reg 17), so all of it is deducted. Counted
+  # rent: (200 - 20) x 52 = 9,360.
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      householder:
+        age: 70
+        is_household_head: true
+        private_pension_income: 15_000
+      lodger:
+        age: 30
+        is_household_head: false
+        rent_paid_as_lodger: 10_400
+    benunits:
+      householder_unit:
+        members: [householder]
+      lodger_unit:
+        members: [lodger]
+    households:
+      household:
+        members: [householder, lodger]
+  output:
+    income_tax: [1_066, 0]
+    property_income_tax: [580, 0]
+    rent_a_room_income_tax: [580, 0]
+    legacy_means_test_income_tax: [1_066, 0]
+    legacy_benefits_home_letting_income: [9_360, 0]
+
+- name: Tax on counted rent-a-room income shares a tax reduction pro rata
+  # 2026-27. Step 4 tax: private pension (36,000 - 12,570) x 20% = 4,686;
+  # rent-a-room income (10,400 - 7,500) x 20% = 580; savings interest
+  # (3,000 - 1,000 personal savings allowance) x 20% = 400, with no starting
+  # rate for savings because non-savings income exceeds the allowances by more
+  # than £5,000; total 5,666. The married couple's allowance reduction
+  # (11,000 x 10% = 1,100, set as an input) leaves income tax of 4,566. The
+  # tests count the pension and the rent but treat interest as capital: the
+  # capital tax of 400 keeps its share of the reduction,
+  # 1,100 x 400 / 5,666 = 77.66, so 322.34 is not deducted, and the tax
+  # deducted is 4,566 - 322.34 = 4,243.66.
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      householder:
+        age: 70
+        is_household_head: true
+        private_pension_income: 36_000
+        savings_interest_income: 3_000
+        married_couples_allowance: 11_000
+      lodger:
+        age: 30
+        is_household_head: false
+        rent_paid_as_lodger: 10_400
+    benunits:
+      householder_unit:
+        members: [householder]
+      lodger_unit:
+        members: [lodger]
+    households:
+      household:
+        members: [householder, lodger]
+  output:
+    rent_a_room_income_tax: [580, 0]
+    savings_income_tax: [400, 0]
+    capped_mcad: [1_100, 0]
+    income_tax: [4_566, 0]
+    legacy_means_test_income_tax: [4_243.66, 0]
+
+- name: UC does not deduct the tax on rent it does not count
+  # 2026-27, England. Earnings 20,000: tax (20,000 - 12,570) x 20% = 1,486,
+  # NI 7,430 x 8% = 594.40. Lodger rent 10,000 gives taxable rent-a-room income
+  # 2,500 and tax 500, so income tax is 1,986. UC counts neither the rent
+  # (reg 66(1)) nor its tax (reg 55(5)(b)): earned income
+  # 20,000 - 1,486 - 594.40 = 17,919.60, as without the lodger.
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      householder:
+        age: 45
+        is_household_head: true
+        employment_income: 20_000
+      lodger:
+        age: 30
+        is_household_head: false
+        rent_paid_as_lodger: 10_000
+    benunits:
+      householder_unit:
+        members: [householder]
+      lodger_unit:
+        members: [lodger]
+    households:
+      household:
+        members: [householder, lodger]
+        region: NORTH_WEST
+  output:
+    income_tax: [1_986, 0]
+    rent_a_room_income_tax_after_reductions: [500, 0]
+    uc_earned_income: [17_919.60, 0]
+
+- name: Welsh CTR for a UC recipient does not add rent from a lodger
+  # WSI 2013/3029 Sch 6 para 9: with a UC award, income is the UC assessment,
+  # which excludes this rent. Here UC (5,000, set as an input) is the only
+  # income, so CTR applicable income is 5,000, not 5,000 + 4,160.
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      householder:
+        age: 45
+        is_household_head: true
+      lodger:
+        age: 30
+        is_household_head: false
+        rent_paid_as_lodger: 5_200
+    benunits:
+      householder_unit:
+        members: [householder]
+        universal_credit: 5_000
+      lodger_unit:
+        members: [lodger]
+    households:
+      household:
+        members: [householder, lodger]
+        region: WALES
+  output:
+    legacy_benefits_home_letting_income: [4_160, 0]
+    council_tax_reduction_applicable_income: [5_000, 0]
diff --git a/policyengine_uk/tests/policy/baseline/gov/dwp/legacy_means_tests/boarders_and_lodgers_non_dependants.yaml b/policyengine_uk/tests/policy/baseline/gov/dwp/legacy_means_tests/boarders_and_lodgers_non_dependants.yaml
new file mode 100644
index 000000000..59a7ed221
--- /dev/null
+++ b/policyengine_uk/tests/policy/baseline/gov/dwp/legacy_means_tests/boarders_and_lodgers_non_dependants.yaml
@@ -0,0 +1,58 @@
+# A boarder or lodger is liable to pay the householder on a commercial basis
+# for their occupation, so is not a non-dependant: UC Regs 2013 Sch 4 para
+# 9(2)(d); HB Regs 2006 reg 3(2)(e)(i); CTR (England) prescribed requirements
+# reg 9(2)(e). An unrelated adult in the household who pays nothing remains a
+# non-dependant.
+
+- name: An adult lodger is not a non-dependant
+  period: 2026
+  input:
+    people:
+      householder:
+        age: 45
+        is_household_head: true
+      lodger:
+        age: 30
+        is_household_head: false
+        rent_paid_as_lodger: 4_000
+    benunits:
+      householder_unit:
+        members: [householder]
+        benunit_rent: 9_000
+      lodger_unit:
+        members: [lodger]
+    households:
+      household:
+        members: [householder, lodger]
+        tenure_type: RENT_PRIVATELY
+  output:
+    pays_rent_to_householder: [false, true]
+    uc_individual_non_dep_deduction_eligible: [false, false]
+    housing_benefit_individual_non_dep_deduction_eligible: [false, false]
+    council_tax_reduction_individual_non_dep_deduction_eligible: [false, false]
+
+- name: The same adult paying nothing is a non-dependant
+  period: 2026
+  input:
+    people:
+      householder:
+        age: 45
+        is_household_head: true
+      adult:
+        age: 30
+        is_household_head: false
+    benunits:
+      householder_unit:
+        members: [householder]
+        benunit_rent: 9_000
+      adult_unit:
+        members: [adult]
+    households:
+      household:
+        members: [householder, adult]
+        tenure_type: RENT_PRIVATELY
+  output:
+    pays_rent_to_householder: [false, false]
+    uc_individual_non_dep_deduction_eligible: [false, true]
+    housing_benefit_individual_non_dep_deduction_eligible: [false, true]
+    council_tax_reduction_individual_non_dep_deduction_eligible: [false, true]
diff --git a/policyengine_uk/tests/policy/baseline/gov/hmrc/income_tax/rent_a_room/rent_a_room_relief.yaml b/policyengine_uk/tests/policy/baseline/gov/hmrc/income_tax/rent_a_room/rent_a_room_relief.yaml
new file mode 100644
index 000000000..6160dbe27
--- /dev/null
+++ b/policyengine_uk/tests/policy/baseline/gov/hmrc/income_tax/rent_a_room/rent_a_room_relief.yaml
@@ -0,0 +1,211 @@
+# Rent-a-room relief (ITTOIA 2005 Part 7 Chapter 1). Receipts up to the
+# individual's limit are not charged (s. 793). Above it the model assumes the
+# s. 800 election: the limit is deducted and no expenses are allowed (s. 797).
+# The basic amount is £4,250 (s. 789(4) as enacted) and £7,500 from 2016-17
+# (SI 2015/1539 arts. 1(2), 2), halved where someone else also receives rent
+# from the residence (ss. 789(3), 790). Rent-a-room receipts are not relievable
+# receipts for the £1,000 property allowance (s. 783BB(2)).
+#
+# Tax figures, 2026-27: personal allowance £12,570; basic rate 20%.
+
+- name: Rent from a lodger within the limit is not taxed
+  # Receipts 6,000 <= 7,500, so nothing is charged. Earnings tax:
+  # (30,000 - 12,570) x 20% = 3,486.
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      householder:
+        age: 45
+        is_household_head: true
+        employment_income: 30_000
+      lodger:
+        age: 30
+        is_household_head: false
+        rent_paid_as_lodger: 6_000
+    benunits:
+      householder_unit:
+        members: [householder]
+      lodger_unit:
+        members: [lodger]
+    households:
+      household:
+        members: [householder, lodger]
+  output:
+    rent_from_boarders_and_lodgers: [6_000, 0]
+    rent_a_room_receipts: [6_000, 0]
+    rent_a_room_relief: [6_000, 0]
+    taxable_rent_a_room_income: [0, 0]
+    taxable_property_income: [0, 0]
+    income_tax: [3_486, 0]
+
+- name: Rent from a lodger above the limit is taxed on the excess
+  # Taxable: 10,000 - 7,500 = 2,500, taxed at 20% = 500 on top of 3,486.
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      householder:
+        age: 45
+        is_household_head: true
+        employment_income: 30_000
+      lodger:
+        age: 30
+        is_household_head: false
+        rent_paid_as_lodger: 10_000
+    benunits:
+      householder_unit:
+        members: [householder]
+      lodger_unit:
+        members: [lodger]
+    households:
+      household:
+        members: [householder, lodger]
+  output:
+    rent_a_room_relief: [7_500, 0]
+    taxable_rent_a_room_income: [2_500, 0]
+    taxable_property_income: [2_500, 0]
+    rent_a_room_income_tax: [500, 0]
+    income_tax: [3_986, 0]
+
+- name: The property allowance does not reduce taxable rent-a-room income
+  # Other property income 500 is covered by the property allowance
+  # (min(500, 1,000)); the rent-a-room excess of 2,500 is not.
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      householder:
+        age: 45
+        is_household_head: true
+        employment_income: 30_000
+        property_income: 500
+      boarder:
+        age: 30
+        is_household_head: false
+        rent_paid_as_boarder: 10_000
+    benunits:
+      householder_unit:
+        members: [householder]
+      boarder_unit:
+        members: [boarder]
+    households:
+      household:
+        members: [householder, boarder]
+  output:
+    property_allowance_deduction: [500, 0]
+    taxable_rent_a_room_income: [2_500, 0]
+    taxable_property_income: [2_500, 0]
+
+- name: The limit was 4,250 before 2016-17
+  # 6,000 - 4,250 = 1,750.
+  period: 2015
+  absolute_error_margin: 0.01
+  input:
+    people:
+      householder:
+        age: 45
+        is_household_head: true
+        employment_income: 30_000
+      lodger:
+        age: 30
+        is_household_head: false
+        rent_paid_as_lodger: 6_000
+    benunits:
+      householder_unit:
+        members: [householder]
+      lodger_unit:
+        members: [lodger]
+    households:
+      household:
+        members: [householder, lodger]
+  output:
+    rent_a_room_limit: [4_250, 4_250]
+    rent_a_room_relief: [4_250, 0]
+    taxable_rent_a_room_income: [1_750, 0]
+
+- name: Two people receiving rent from the home each have half the limit
+  # The householder receives the lodger's 6,000; the partner sublets part of
+  # the home for 2,000. Each limit is 7,500 / 2 = 3,750. Householder:
+  # 6,000 - 3,750 = 2,250 taxable; partner: 2,000 < 3,750, nothing taxable.
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      householder:
+        age: 45
+        is_household_head: true
+      partner:
+        age: 44
+        is_household_head: false
+        sublet_income: 2_000
+      lodger:
+        age: 30
+        is_household_head: false
+        rent_paid_as_lodger: 6_000
+    benunits:
+      couple:
+        members: [householder, partner]
+      lodger_unit:
+        members: [lodger]
+    households:
+      household:
+        members: [householder, partner, lodger]
+  output:
+    rent_a_room_receipts: [6_000, 2_000, 0]
+    # The lodger receives nothing, so keeps the basic amount.
+    rent_a_room_limit: [3_750, 3_750, 7_500]
+    taxable_rent_a_room_income: [2_250, 0, 0]
+
+- name: Rent paid by someone in the householder's own benefit unit is not received
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      householder:
+        age: 45
+        is_household_head: true
+      partner:
+        age: 44
+        is_household_head: false
+        rent_paid_as_lodger: 6_000
+    benunits:
+      couple:
+        members: [householder, partner]
+    households:
+      household:
+        members: [householder, partner]
+  output:
+    rent_from_boarders_and_lodgers: [0, 0]
+    pays_rent_to_householder: [false, false]
+
+- name: Tax credits count only the taxable rent-a-room income
+  # 2023-24. Taxable rent-a-room income: 10,000 - 7,500 = 2,500. Step 1 income
+  # (pensions, savings, dividends, property): 2,500 less the £300 disregard =
+  # 2,200. Step 2: earnings 10,000. Total 12,200.
+  period: 2023
+  absolute_error_margin: 0.01
+  input:
+    people:
+      householder:
+        age: 45
+        is_household_head: true
+        employment_income: 10_000
+      lodger:
+        age: 30
+        is_household_head: false
+        rent_paid_as_lodger: 10_000
+    benunits:
+      householder_unit:
+        members: [householder]
+        income_support: 0
+        esa_income: 0
+        jsa_income: 0
+      lodger_unit:
+        members: [lodger]
+    households:
+      household:
+        members: [householder, lodger]
+  output:
+    taxable_rent_a_room_income: [2_500, 0]
+    tax_credits_applicable_income: [12_200, 0]
diff --git a/policyengine_uk/tests/test_boarder_lodger_rent_properties.py b/policyengine_uk/tests/test_boarder_lodger_rent_properties.py
new file mode 100644
index 000000000..e1b963bfa
--- /dev/null
+++ b/policyengine_uk/tests/test_boarder_lodger_rent_properties.py
@@ -0,0 +1,283 @@
+"""Property-based tests for rent from boarders, lodgers and sub-tenants.
+
+A household head may receive rent from boarders and lodgers who live in the
+household in their own benefit units (rent_paid_as_boarder and
+rent_paid_as_lodger, recorded on the payer), and from a sub-tenant outside it
+(sublet_income).
+
+Invariants, for any generated household:
+
+1. Conservation: the rent the head receives equals the rent paid by members
+   outside the head's benefit unit, and nobody else receives any.
+2. Rent-a-room bounds: 0 <= relief <= receipts; the limit is half the basic
+   amount exactly when the person and someone else in the household both
+   have receipts, and the basic amount otherwise; taxable rent-a-room income
+   = max(0, receipts - limit).
+3. Disregards: the counted home-letting income is between nil and the rent
+   received, and equals the statutory closed form (boarders: half the excess
+   over £20 a week each; lodgers: the excess over £20 a week, per person at
+   pension age and per lodger family at working age; sub-tenants: the excess
+   over £20 a week).
+4. Monotone: more rent from a boarder or lodger who already pays never lowers
+   taxable rent-a-room income or counted home-letting income, and never raises
+   Income Support, Housing Benefit, Pension Credit or council tax reduction.
+5. Boarders keep more: the same weekly amount counts no more when paid for
+   board and lodging than when paid for lodging only.
+6. Universal Credit unearned income and household market income do not depend
+   on the rent paid between members of the household.
+7. Where a programme does not count this rent, it does not deduct the tax on
+   it either: UC earned income, and council tax reduction income under the
+   Scottish working-age scheme and the Welsh universal credit route, do not
+   change when the rent changes.
+8. Tax: legacy_means_test_income_tax is between nil and income tax.
+"""
+
+import numpy as np
+from hypothesis import HealthCheck, given, settings
+from hypothesis import strategies as st
+
+from policyengine_uk import Simulation
+
+PROPERTY_SETTINGS = settings(
+    max_examples=10,
+    deadline=None,
+    derandomize=True,
+    suppress_health_check=[HealthCheck.too_slow, HealthCheck.data_too_large],
+)
+YEARS = [2025, 2026]
+WEEKS = 52
+DISREGARD = 20
+BASIC_AMOUNT = 7_500
+AWARDS = ["income_support", "housing_benefit", "pension_credit", "council_tax_benefit"]
+rent = st.one_of(st.just(0.0), st.floats(100, 20_000))
+
+
+@st.composite
+def households(draw):
+    pension_age = draw(st.booleans())
+    age = st.integers(67, 90) if pension_age else st.integers(25, 60)
+    head_unit = [
+        dict(age=draw(age), employment_income=draw(st.floats(0, 25_000)))
+        for _ in range(draw(st.integers(1, 2)))
+    ]
+    payers = []
+    for _ in range(draw(st.integers(0, 2))):
+        kind = draw(st.sampled_from(["rent_paid_as_boarder", "rent_paid_as_lodger"]))
+        payers.append(
+            [
+                {"age": draw(st.integers(19, 60)), kind: draw(rent)}
+                for _ in range(draw(st.integers(1, 2)))
+            ]
+        )
+    return dict(
+        head_unit=head_unit,
+        payers=payers,
+        sublet=draw(st.one_of(st.just(0.0), st.floats(0, 8_000))),
+        partner_sublet=draw(st.one_of(st.just(0.0), st.floats(100, 8_000))),
+        tenure=draw(st.sampled_from(["RENT_PRIVATELY", "OWNED_OUTRIGHT"])),
+        region=draw(st.sampled_from(["NORTH_WEST", "LONDON", "WALES", "SCOTLAND"])),
+    )
+
+
+def situation(h, year, scale=1.0, as_kind=None):
+    people, benunits = {}, {}
+    names = []
+    for i, attrs in enumerate(h["head_unit"]):
+        name = f"head_{i}"
+        people[name] = {
+            "age": {year: attrs["age"]},
+            "employment_income": {year: attrs["employment_income"]},
+            "is_household_head": {year: i == 0},
+            "sublet_income": {year: h["sublet"] if i == 0 else h["partner_sublet"]},
+        }
+        names.append(name)
+    benunits["head_unit"] = {"members": list(names)}
+    for j, unit in enumerate(h["payers"]):
+        members = []
+        for k, attrs in enumerate(unit):
+            name = f"payer_{j}_{k}"
+            person = {"age": {year: attrs["age"]}, "is_household_head": {year: False}}
+            for kind in ("rent_paid_as_boarder", "rent_paid_as_lodger"):
+                if kind in attrs:
+                    target = as_kind or kind
+                    person[target] = {year: attrs[kind] * scale}
+            people[name] = person
+            members.append(name)
+        benunits[f"payer_{j}"] = {"members": members}
+        names += members
+    return {
+        "people": people,
+        "benunits": benunits,
+        "households": {
+            "household": {
+                "members": names,
+                "tenure_type": {year: h["tenure"]},
+                "region": {year: h["region"]},
+                "rent": {year: 8_000.0 if h["tenure"] == "RENT_PRIVATELY" else 0.0},
+                "council_tax": {year: 1_500.0},
+            }
+        },
+    }
+
+
+def calculate(h, year, variables, **kwargs):
+    sim = Simulation(situation=situation(h, year, **kwargs))
+    return {v: np.asarray(sim.calculate(v, year), dtype=float) for v in variables}
+
+
+def per_week(annual):
+    return annual / WEEKS
+
+
+def payments(h, kind=None):
+    return [
+        [
+            a.get(kind, 0.0) if kind else sum(v for k, v in a.items() if k != "age")
+            for a in unit
+        ]
+        for unit in h["payers"]
+    ]
+
+
+@PROPERTY_SETTINGS
+@given(households(), st.sampled_from(YEARS))
+def test_rent_is_received_by_the_head_and_conserved(h, year):
+    v = calculate(h, year, ["rent_from_boarders_and_lodgers"])
+    received = v["rent_from_boarders_and_lodgers"]
+    paid = sum(sum(unit) for unit in payments(h))
+    np.testing.assert_allclose(received.sum(), paid, rtol=1e-6, atol=0.01)
+    assert np.all(received[1:] == 0)
+
+
+@PROPERTY_SETTINGS
+@given(households(), st.sampled_from(YEARS))
+def test_rent_a_room_bounds(h, year):
+    v = calculate(
+        h,
+        year,
+        [
+            "rent_a_room_receipts",
+            "rent_a_room_limit",
+            "rent_a_room_relief",
+            "taxable_rent_a_room_income",
+        ],
+    )
+    receipts, limit = v["rent_a_room_receipts"], v["rent_a_room_limit"]
+    receives = receipts > 0
+    shared = receives & (receives.sum() - receives > 0)
+    np.testing.assert_allclose(
+        limit, np.where(shared, BASIC_AMOUNT / 2, BASIC_AMOUNT), atol=0.01
+    )
+    assert np.all(v["rent_a_room_relief"] >= 0)
+    assert np.all(v["rent_a_room_relief"] <= receipts + 0.01)
+    np.testing.assert_allclose(
+        v["taxable_rent_a_room_income"], np.maximum(0, receipts - limit), atol=0.01
+    )
+
+
+@PROPERTY_SETTINGS
+@given(households(), st.sampled_from(YEARS))
+def test_home_letting_income_closed_form(h, year):
+    sim = Simulation(situation=situation(h, year))
+    counted = np.asarray(sim.calculate("legacy_benefits_home_letting_income", year))
+    pension_age = bool(
+        np.asarray(sim.calculate("is_SP_age", year))[: len(h["head_unit"])].any()
+    )
+    board = sum(
+        0.5 * max(0, per_week(x) - DISREGARD)
+        for unit in payments(h, "rent_paid_as_boarder")
+        for x in unit
+    )
+    lodgers = payments(h, "rent_paid_as_lodger")
+    if pension_age:
+        lodging = sum(max(0, per_week(x) - DISREGARD) for unit in lodgers for x in unit)
+    else:
+        lodging = sum(max(0, per_week(sum(unit)) - DISREGARD) for unit in lodgers)
+    sublet_received = h["sublet"] + (
+        h["partner_sublet"] if len(h["head_unit"]) > 1 else 0.0
+    )
+    # #1995 sums the claimant's and partner's sublet income before one
+    # disregard (one occupier assumed).
+    sublet = max(0, per_week(sublet_received) - DISREGARD)
+    expected = (board + lodging + sublet) * WEEKS
+    np.testing.assert_allclose(counted[0], expected, rtol=1e-6, atol=0.01)
+    assert np.all(counted[1:] == 0)
+    received = sum(sum(unit) for unit in payments(h)) + sublet_received
+    assert 0 <= counted[0] <= received + 0.01
+
+
+@PROPERTY_SETTINGS
+@given(households(), st.sampled_from(YEARS), st.floats(1.1, 4))
+def test_more_rent_is_monotone(h, year, scale):
+    variables = [
+        "taxable_rent_a_room_income",
+        "legacy_benefits_home_letting_income",
+    ] + AWARDS
+    base = calculate(h, year, variables)
+    more = calculate(h, year, variables, scale=scale)
+    for v in ["taxable_rent_a_room_income", "legacy_benefits_home_letting_income"]:
+        assert np.all(more[v] >= base[v] - 0.01), v
+    for v in AWARDS:
+        assert np.all(more[v] <= base[v] + 0.01), v
+
+
+@PROPERTY_SETTINGS
+@given(households(), st.sampled_from(YEARS))
+def test_board_and_lodging_counts_no_more_than_lodging(h, year):
+    v = "legacy_benefits_home_letting_income"
+    as_boarders = calculate(h, year, [v], as_kind="rent_paid_as_boarder")[v]
+    as_lodgers = calculate(h, year, [v], as_kind="rent_paid_as_lodger")[v]
+    pension_age = calculate(h, year, ["is_SP_age"])["is_SP_age"][
+        : len(h["head_unit"])
+    ].any()
+    if pension_age:
+        # Per-person lodger disregard at pension age: boarders keep at least
+        # as much per person.
+        assert np.all(as_boarders <= as_lodgers + 0.01)
+
+
+@PROPERTY_SETTINGS
+@given(households(), st.sampled_from(YEARS))
+def test_rent_within_the_household_changes_no_uc_income_or_market_income(h, year):
+    variables = ["uc_unearned_income", "household_market_income"]
+    with_rent = calculate(h, year, variables)
+    without = calculate(h, year, variables, scale=0.0)
+    for v in variables:
+        np.testing.assert_allclose(with_rent[v], without[v], atol=0.01, err_msg=v)
+
+
+@PROPERTY_SETTINGS
+@given(households(), st.sampled_from(YEARS))
+def test_legacy_means_test_income_tax_bounds(h, year):
+    v = calculate(h, year, ["legacy_means_test_income_tax", "income_tax"])
+    assert np.all(v["legacy_means_test_income_tax"] >= 0)
+    assert np.all(v["legacy_means_test_income_tax"] <= v["income_tax"] + 0.01)
+
+
+@PROPERTY_SETTINGS
+@given(households(), st.sampled_from(YEARS), st.floats(0.3, 0.9))
+def test_programmes_that_exclude_the_rent_ignore_its_tax(h, year, scale):
+    # Both runs keep every payment positive, so non-dependant status is fixed.
+    variables = [
+        "uc_earned_income",
+        "council_tax_reduction_applicable_income",
+        "universal_credit",
+        "is_SP_age",
+    ]
+    full = calculate(h, year, variables)
+    part = calculate(h, year, variables, scale=scale)
+    np.testing.assert_allclose(
+        full["uc_earned_income"], part["uc_earned_income"], atol=0.01
+    )
+    head_unit = 0
+    working_age = not full["is_SP_age"][: len(h["head_unit"])].any()
+    on_uc = full["universal_credit"][head_unit] > 0
+    excluded = (h["region"] == "SCOTLAND" and (working_age or on_uc)) or (
+        h["region"] == "WALES" and on_uc
+    )
+    if excluded and (part["universal_credit"][head_unit] > 0) == on_uc:
+        np.testing.assert_allclose(
+            full["council_tax_reduction_applicable_income"][head_unit],
+            part["council_tax_reduction_applicable_income"][head_unit],
+            atol=0.01,
+        )
diff --git a/policyengine_uk/variables/gov/dwp/housing_benefit/non_dep_deduction/housing_benefit_individual_non_dep_deduction_eligible.py b/policyengine_uk/variables/gov/dwp/housing_benefit/non_dep_deduction/housing_benefit_individual_non_dep_deduction_eligible.py
index 37ea75a31..00913bc2a 100644
--- a/policyengine_uk/variables/gov/dwp/housing_benefit/non_dep_deduction/housing_benefit_individual_non_dep_deduction_eligible.py
+++ b/policyengine_uk/variables/gov/dwp/housing_benefit/non_dep_deduction/housing_benefit_individual_non_dep_deduction_eligible.py
@@ -6,9 +6,13 @@ class housing_benefit_individual_non_dep_deduction_eligible(Variable):
     entity = Person
     label = "eligible person for the Housing Benefit non-dependent deduction"
     definition_period = YEAR
+    reference = "https://www.legislation.gov.uk/uksi/2006/213/regulation/3"
 
     def formula(person, period, parameters):
         rent_liable = person.benunit("benunit_is_rent_liable", period)
         p = parameters(period).gov.dwp.housing_benefit.non_dep_deduction
         age_eligible = person("age", period) >= p.age_threshold
-        return age_eligible & ~rent_liable
+        # A boarder or lodger is liable to pay the claimant on a commercial
+        # basis for their occupation, so is not a non-dependant (reg 3(2)(e)(i)).
+        commercial = person("pays_rent_to_householder", period)
+        return age_eligible & ~rent_liable & ~commercial
diff --git a/policyengine_uk/variables/gov/dwp/legacy_benefits_home_letting_income.py b/policyengine_uk/variables/gov/dwp/legacy_benefits_home_letting_income.py
index 2cf125e31..aa9a4be53 100644
--- a/policyengine_uk/variables/gov/dwp/legacy_benefits_home_letting_income.py
+++ b/policyengine_uk/variables/gov/dwp/legacy_benefits_home_letting_income.py
@@ -7,19 +7,23 @@ class legacy_benefits_home_letting_income(Variable):
     label = "Rent from letting part of the home counted in the legacy means tests"
     documentation = (
         "Rent the claimant and any partner receive for letting part of the home "
-        "they live in (sublet_income), after the weekly sub-tenant disregard. "
-        "The legacy means tests treat other income derived from capital, such as "
-        "rent from other property, interest and dividends, as capital, but the "
-        "home is disregarded capital, so rent for part of it stays income: "
-        "Income Support Schedule 9 paragraph 19, Housing Benefit Schedule 5 "
-        "paragraph 22, and for claimants over the qualifying age for State "
-        "Pension Credit Pension Credit regulation 15(5)(i) with Schedule IV "
-        "paragraph 9 and pension-age Housing Benefit regulation 29(1)(v) with "
-        "Schedule 5 paragraph 10. The disregard applies per occupier; the data "
-        "give one annual amount and no count of occupiers, so the model assumes "
-        "one. The pension-age amount applies when the claimant or partner is "
-        "over State Pension age, which stands in for the qualifying age for "
-        "State Pension Credit; the two amounts have been equal since April "
+        "they live in, after the weekly disregards. The legacy means tests treat "
+        "other income derived from capital, such as rent from other property, "
+        "interest and dividends, as capital, but the home is disregarded "
+        "capital, so rent for part of it stays income. Three sources count. "
+        "(1) Rent from a sub-tenant outside the household (sublet_income), less "
+        "the sub-tenant disregard; the data give one annual amount and no count "
+        "of occupiers, so the model assumes one. (2) Rent from lodgers in the "
+        "household, paid to the household head, less the same disregard: per "
+        "person for claimants over the qualifying age for State Pension Credit, "
+        "whose rules disregard 'the amount paid by that person', and per lodger "
+        "family for working-age claimants, whose rules aggregate payments by "
+        "'that person or a member of his family'. (3) Payments for board and "
+        "lodging, paid to the household head, less the board and lodging "
+        "disregard for each boarder: the first £20 a week and half the excess. "
+        "The pension-age amounts apply when the claimant or partner is over "
+        "State Pension age, which stands in for the qualifying age for State "
+        "Pension Credit; the sub-tenant amounts have been equal since April "
         "2008. The calculation is annual, so a year with an April change uses "
         "the amount in force at the start of the year."
     )
@@ -27,21 +31,61 @@ class legacy_benefits_home_letting_income(Variable):
     unit = GBP
     reference = [
         "https://www.legislation.gov.uk/uksi/1987/1967/schedule/9/paragraph/19",
+        "https://www.legislation.gov.uk/uksi/1987/1967/schedule/9/paragraph/20",
         "https://www.legislation.gov.uk/uksi/2006/213/schedule/5/paragraph/22",
+        "https://www.legislation.gov.uk/uksi/2006/213/schedule/5/paragraph/42",
         "https://www.legislation.gov.uk/uksi/2006/214/regulation/29",
+        "https://www.legislation.gov.uk/uksi/2006/214/schedule/5/paragraph/9",
         "https://www.legislation.gov.uk/uksi/2006/214/schedule/5/paragraph/10",
         "https://www.legislation.gov.uk/uksi/2002/1792/regulation/15",
+        "https://www.legislation.gov.uk/uksi/2002/1792/schedule/IV/paragraph/8",
         "https://www.legislation.gov.uk/uksi/2002/1792/schedule/IV/paragraph/9",
     ]
 
     def formula(benunit, period, parameters):
-        p = parameters(period).gov.dwp.legacy_means_tests.sub_tenant_rent_disregard
+        p = parameters(period).gov.dwp.legacy_means_tests
+        sub_tenant = p.sub_tenant_rent_disregard
+        board = p.board_and_lodging_disregard
         person = benunit.members
         claimant_or_partner = person("is_claimant_or_partner", period)
-        weekly_rent = (
+        pension_age = benunit.any(person("is_SP_age", period) & claimant_or_partner)
+
+        weekly_sublet = (
             benunit.sum(person("sublet_income", period) * claimant_or_partner)
             / WEEKS_IN_YEAR
         )
-        pension_age = benunit.any(person("is_SP_age", period) & claimant_or_partner)
-        disregard = where(pension_age, p.pension_age, p.working_age)
-        return max_(0, weekly_rent - disregard) * WEEKS_IN_YEAR
+        sublet_disregard = where(
+            pension_age, sub_tenant.pension_age, sub_tenant.working_age
+        )
+        counted_sublet = max_(0, weekly_sublet - sublet_disregard)
+
+        # Boarders and lodgers are household members outside the head's
+        # benefit unit; what each pays counts for the head's benefit unit when
+        # the head is its claimant or partner.
+        head = person("is_household_head", period)
+        pays_head = ~person.benunit.any(head)
+        boarder = person("rent_paid_as_boarder", period) / WEEKS_IN_YEAR * pays_head
+        lodger = person("rent_paid_as_lodger", period) / WEEKS_IN_YEAR * pays_head
+        counted_board = (1 - board.excess_rate) * max_(0, boarder - board.amount)
+        counted_lodger_pension_age = max_(0, lodger - sub_tenant.pension_age)
+        family_lodger = person.benunit.sum(lodger)
+        family_share = np.divide(
+            lodger,
+            family_lodger,
+            out=np.zeros_like(lodger),
+            where=family_lodger > 0,
+        )
+        counted_lodger_working_age = (
+            max_(0, family_lodger - sub_tenant.working_age) * family_share
+        )
+        household = person.household
+        from_occupiers = where(
+            pension_age,
+            benunit.max(household.sum(counted_board + counted_lodger_pension_age)),
+            benunit.max(household.sum(counted_board + counted_lodger_working_age)),
+        )
+        # Split by heads if more than one is flagged.
+        head_share = benunit.sum(head & claimant_or_partner) / max_(
+            benunit.max(household.sum(head)), 1
+        )
+        return (counted_sublet + from_occupiers * head_share) * WEEKS_IN_YEAR
diff --git a/policyengine_uk/variables/gov/dwp/legacy_means_test_income_tax.py b/policyengine_uk/variables/gov/dwp/legacy_means_test_income_tax.py
index f8139532e..2971d9af3 100644
--- a/policyengine_uk/variables/gov/dwp/legacy_means_test_income_tax.py
+++ b/policyengine_uk/variables/gov/dwp/legacy_means_test_income_tax.py
@@ -13,7 +13,9 @@ class legacy_means_test_income_tax(Variable):
         "council tax reduction schemes' equivalents), and they treat savings "
         "interest, dividends and property income as capital, not income. So this "
         "is the tax calculated on the person's other income (earned_income_tax, "
-        "which covers earnings, pensions and taxable benefits) at Step 4 of "
+        "which covers earnings, pensions and taxable benefits, plus the tax on "
+        "rent-a-room income above the limit: rent from boarders, lodgers and "
+        "sub-tenants in the home is income the tests count) at Step 4 of "
         "Income Tax Act 2007 s.23, less that income's share of the Step 6 tax "
         "reductions (the married couple's allowance and other tax credits). "
         "Neither tax law nor the benefit regulations say which income a "
@@ -41,11 +43,17 @@ def formula(person, period, parameters):
         p = parameters(period).gov.hmrc.income_tax
         # Step 4 tax on the income the means tests count, and on the income
         # they treat as capital.
-        counted = person("earned_income_tax", period)
-        capital = add(
-            person,
-            period,
-            ["savings_income_tax", "dividend_income_tax", "property_income_tax"],
+        # Tax on rent-a-room income sits inside property income tax, but the
+        # tests count that rent, so its tax moves from capital to counted.
+        rent_a_room_tax = person("rent_a_room_income_tax", period)
+        counted = person("earned_income_tax", period) + rent_a_room_tax
+        capital = (
+            add(
+                person,
+                period,
+                ["savings_income_tax", "dividend_income_tax", "property_income_tax"],
+            )
+            - rent_a_room_tax
         )
         before_reductions = counted + capital
         # Step 7 charges: everything income tax adds beyond the Step 4 tax.
diff --git a/policyengine_uk/variables/gov/dwp/tax_credits_applicable_income.py b/policyengine_uk/variables/gov/dwp/tax_credits_applicable_income.py
index 1c698c192..1f954fc76 100644
--- a/policyengine_uk/variables/gov/dwp/tax_credits_applicable_income.py
+++ b/policyengine_uk/variables/gov/dwp/tax_credits_applicable_income.py
@@ -26,6 +26,8 @@ def formula(benunit, period, parameters):
             "savings_interest_income",
             "dividend_income",
             "property_income",
+            # Rent-a-room receipts count only where income tax charges them.
+            "taxable_rent_a_room_income",
         ]
         income = add_for_members(benunit, period, STEP_1_COMPONENTS, members)
         income = max_(income - TC.means_test.non_earned_disregard, 0)
diff --git a/policyengine_uk/variables/gov/dwp/universal_credit/housing_costs_element/non_dep_deduction/uc_individual_non_dep_deduction_eligible.py b/policyengine_uk/variables/gov/dwp/universal_credit/housing_costs_element/non_dep_deduction/uc_individual_non_dep_deduction_eligible.py
index abd986925..a42dbbe2f 100644
--- a/policyengine_uk/variables/gov/dwp/universal_credit/housing_costs_element/non_dep_deduction/uc_individual_non_dep_deduction_eligible.py
+++ b/policyengine_uk/variables/gov/dwp/universal_credit/housing_costs_element/non_dep_deduction/uc_individual_non_dep_deduction_eligible.py
@@ -6,6 +6,7 @@ class uc_individual_non_dep_deduction_eligible(Variable):
     entity = Person
     label = "Eligible person for the Universal Credit non-dependent deduction"
     definition_period = YEAR
+    reference = "https://www.legislation.gov.uk/uksi/2013/376/schedule/4/paragraph/9"
 
     def formula(person, period, parameters):
         not_rent_liable = ~person.benunit("benunit_is_rent_liable", period)
@@ -15,4 +16,7 @@ def formula(person, period, parameters):
         age = person("age", period)
         age_eligible = age >= p.age_threshold
         exempt = person("uc_non_dep_deduction_exempt", period)
-        return ~exempt & age_eligible & not_rent_liable
+        # A boarder or lodger is liable to pay on a commercial basis for their
+        # occupation, so is not a non-dependant (Sch 4 para 9(2)(d)).
+        commercial = person("pays_rent_to_householder", period)
+        return ~exempt & age_eligible & not_rent_liable & ~commercial
diff --git a/policyengine_uk/variables/gov/dwp/universal_credit/income/uc_earned_income.py b/policyengine_uk/variables/gov/dwp/universal_credit/income/uc_earned_income.py
index 6e496b868..538f10fe0 100644
--- a/policyengine_uk/variables/gov/dwp/universal_credit/income/uc_earned_income.py
+++ b/policyengine_uk/variables/gov/dwp/universal_credit/income/uc_earned_income.py
@@ -28,4 +28,11 @@ def formula(benunit, period, parameters):
             ["uc_work_allowance", "tax", "pension_contributions"],
             members,
         )
+        # UC does not count rent from boarders, lodgers or sub-tenants (reg
+        # 66(1)), so the tax on it is not tax in respect of any employment
+        # (reg 55(5)(b)) and is not deducted. The rest of `tax` is wider than
+        # reg 55(5)(b) allows; that is #1942.
+        disregards -= add_for_members(
+            benunit, period, ["rent_a_room_income_tax_after_reductions"], members
+        )
         return max_(0, personal_gross_earned_income - disregards)
diff --git a/policyengine_uk/variables/gov/hmrc/income_tax/bases/taxable_property_income.py b/policyengine_uk/variables/gov/hmrc/income_tax/bases/taxable_property_income.py
index d70b06548..4f3876ba0 100644
--- a/policyengine_uk/variables/gov/hmrc/income_tax/bases/taxable_property_income.py
+++ b/policyengine_uk/variables/gov/hmrc/income_tax/bases/taxable_property_income.py
@@ -5,11 +5,23 @@ class taxable_property_income(Variable):
     value_type = float
     entity = Person
     label = "Amount of property income that is taxable"
-    definition_period = YEAR
-    reference = dict(
-        title="Income Tax (Trading and Other Income) Act 2005, s. 268",
-        href="https://www.legislation.gov.uk/ukpga/2005/5/section/268",
+    documentation = (
+        "Property income less the property allowance, plus rent-a-room "
+        "receipts above the rent-a-room limit, which are profits of the same "
+        "UK property business but are not relievable receipts for the "
+        "property allowance."
     )
+    definition_period = YEAR
+    reference = [
+        dict(
+            title="Income Tax (Trading and Other Income) Act 2005, s. 268",
+            href="https://www.legislation.gov.uk/ukpga/2005/5/section/268",
+        ),
+        dict(
+            title="Income Tax (Trading and Other Income) Act 2005, s. 783BB(2)",
+            href="https://www.legislation.gov.uk/ukpga/2005/5/section/783BB",
+        ),
+    ]
     unit = GBP
 
     def formula(person, period, parameters):
@@ -17,4 +29,4 @@ def formula(person, period, parameters):
             0,
             person("property_income", period)
             - person("property_allowance_deduction", period),
-        )
+        ) + person("taxable_rent_a_room_income", period)
diff --git a/policyengine_uk/variables/gov/hmrc/income_tax/rent_a_room/rent_a_room_income_tax.py b/policyengine_uk/variables/gov/hmrc/income_tax/rent_a_room/rent_a_room_income_tax.py
new file mode 100644
index 000000000..d8c3b0d72
--- /dev/null
+++ b/policyengine_uk/variables/gov/hmrc/income_tax/rent_a_room/rent_a_room_income_tax.py
@@ -0,0 +1,26 @@
+from policyengine_uk.model_api import *
+
+
+class rent_a_room_income_tax(Variable):
+    value_type = float
+    entity = Person
+    label = "income tax on rent-a-room income"
+    documentation = (
+        "The share of income tax on property income that falls on taxable "
+        "rent-a-room income, in proportion to its share of taxable property "
+        "income. The legacy means tests count rent-a-room receipts as income "
+        "and disregard the tax paid on income they count."
+    )
+    definition_period = YEAR
+    unit = GBP
+
+    def formula(person, period, parameters):
+        taxable_rent_a_room = person("taxable_rent_a_room_income", period)
+        taxable_property = person("taxable_property_income", period)
+        share = np.divide(
+            taxable_rent_a_room,
+            taxable_property,
+            out=np.zeros_like(taxable_property),
+            where=taxable_property > 0,
+        )
+        return person("property_income_tax", period) * share
diff --git a/policyengine_uk/variables/gov/hmrc/income_tax/rent_a_room/rent_a_room_income_tax_after_reductions.py b/policyengine_uk/variables/gov/hmrc/income_tax/rent_a_room/rent_a_room_income_tax_after_reductions.py
new file mode 100644
index 000000000..85e6c7606
--- /dev/null
+++ b/policyengine_uk/variables/gov/hmrc/income_tax/rent_a_room/rent_a_room_income_tax_after_reductions.py
@@ -0,0 +1,41 @@
+from policyengine_uk.model_api import *
+
+
+class rent_a_room_income_tax_after_reductions(Variable):
+    value_type = float
+    entity = Person
+    label = "income tax on rent-a-room income after tax reductions"
+    documentation = (
+        "The tax on taxable rent-a-room income less its share of the Step 6 "
+        "tax reductions, shared in proportion to the Step 4 tax on each kind "
+        "of income as legacy_means_test_income_tax does. It is the part of "
+        "income tax paid on this rent, which programmes that do not count the "
+        "rent must not deduct from the income they do count."
+    )
+    definition_period = YEAR
+    unit = GBP
+    reference = "https://www.legislation.gov.uk/ukpga/2007/3/section/23"
+
+    def formula(person, period, parameters):
+        p = parameters(period).gov.hmrc.income_tax
+        rent_a_room_tax = person("rent_a_room_income_tax", period)
+        before_reductions = add(
+            person,
+            period,
+            [
+                "earned_income_tax",
+                "savings_income_tax",
+                "dividend_income_tax",
+                "property_income_tax",
+            ],
+        )
+        reductions = min_(
+            add(person, period, p.income_tax_subtractions), before_reductions
+        )
+        share = np.divide(
+            rent_a_room_tax,
+            before_reductions,
+            out=np.zeros_like(rent_a_room_tax, dtype=float),
+            where=before_reductions > 0,
+        )
+        return rent_a_room_tax - reductions * share
diff --git a/policyengine_uk/variables/gov/hmrc/income_tax/rent_a_room/rent_a_room_limit.py b/policyengine_uk/variables/gov/hmrc/income_tax/rent_a_room/rent_a_room_limit.py
new file mode 100644
index 000000000..06f51f696
--- /dev/null
+++ b/policyengine_uk/variables/gov/hmrc/income_tax/rent_a_room/rent_a_room_limit.py
@@ -0,0 +1,25 @@
+from policyengine_uk.model_api import *
+
+
+class rent_a_room_limit(Variable):
+    value_type = float
+    entity = Person
+    label = "rent-a-room relief limit"
+    documentation = (
+        "The basic amount, or half of it where the individual does not meet "
+        "the exclusive receipts condition. The model takes the condition to "
+        "fail where the individual and another member of the household both "
+        "have rent-a-room receipts from the home."
+    )
+    definition_period = YEAR
+    unit = GBP
+    reference = [
+        "https://www.legislation.gov.uk/ukpga/2005/5/section/789",
+        "https://www.legislation.gov.uk/ukpga/2005/5/section/790",
+    ]
+
+    def formula(person, period, parameters):
+        basic_amount = parameters(period).gov.hmrc.income_tax.rent_a_room.basic_amount
+        receives = person("rent_a_room_receipts", period) > 0
+        others_receive = person.household.sum(receives) - receives > 0
+        return where(receives & others_receive, basic_amount / 2, basic_amount)
diff --git a/policyengine_uk/variables/gov/hmrc/income_tax/rent_a_room/rent_a_room_receipts.py b/policyengine_uk/variables/gov/hmrc/income_tax/rent_a_room/rent_a_room_receipts.py
new file mode 100644
index 000000000..d01c781e2
--- /dev/null
+++ b/policyengine_uk/variables/gov/hmrc/income_tax/rent_a_room/rent_a_room_receipts.py
@@ -0,0 +1,18 @@
+from policyengine_uk.model_api import *
+
+
+class rent_a_room_receipts(Variable):
+    value_type = float
+    entity = Person
+    label = "rent-a-room receipts"
+    documentation = (
+        "Receipts for the use of furnished accommodation in the individual's "
+        "only or main residence, including meals and other services supplied "
+        "with it: rent from boarders and lodgers who live in the household, "
+        "and rent from letting part of the home to someone outside it. The "
+        "model treats all of it as furnished accommodation."
+    )
+    definition_period = YEAR
+    unit = GBP
+    reference = "https://www.legislation.gov.uk/ukpga/2005/5/section/786"
+    adds = ["rent_from_boarders_and_lodgers", "sublet_income"]
diff --git a/policyengine_uk/variables/gov/hmrc/income_tax/rent_a_room/rent_a_room_relief.py b/policyengine_uk/variables/gov/hmrc/income_tax/rent_a_room/rent_a_room_relief.py
new file mode 100644
index 000000000..bb2a8c263
--- /dev/null
+++ b/policyengine_uk/variables/gov/hmrc/income_tax/rent_a_room/rent_a_room_relief.py
@@ -0,0 +1,27 @@
+from policyengine_uk.model_api import *
+
+
+class rent_a_room_relief(Variable):
+    value_type = float
+    entity = Person
+    label = "rent-a-room relief"
+    documentation = (
+        "Rent-a-room receipts not charged to income tax. Receipts up to the "
+        "limit are not brought into account (full relief). Above the limit "
+        "the model assumes the individual elects for the alternative method, "
+        "under which the limit is deducted from the receipts and no expenses "
+        "are allowed; the data hold no expenses for this income."
+    )
+    definition_period = YEAR
+    unit = GBP
+    reference = [
+        "https://www.legislation.gov.uk/ukpga/2005/5/section/793",
+        "https://www.legislation.gov.uk/ukpga/2005/5/section/797",
+        "https://www.legislation.gov.uk/ukpga/2005/5/section/800",
+    ]
+
+    def formula(person, period, parameters):
+        return min_(
+            person("rent_a_room_receipts", period),
+            person("rent_a_room_limit", period),
+        )
diff --git a/policyengine_uk/variables/gov/hmrc/income_tax/rent_a_room/taxable_rent_a_room_income.py b/policyengine_uk/variables/gov/hmrc/income_tax/rent_a_room/taxable_rent_a_room_income.py
new file mode 100644
index 000000000..b212e2e4d
--- /dev/null
+++ b/policyengine_uk/variables/gov/hmrc/income_tax/rent_a_room/taxable_rent_a_room_income.py
@@ -0,0 +1,23 @@
+from policyengine_uk.model_api import *
+
+
+class taxable_rent_a_room_income(Variable):
+    value_type = float
+    entity = Person
+    label = "taxable rent-a-room income"
+    documentation = (
+        "Rent-a-room receipts above the individual's limit, brought into "
+        "account as profits of a UK property business. They are not "
+        "relievable receipts for the property allowance."
+    )
+    definition_period = YEAR
+    unit = GBP
+    reference = [
+        "https://www.legislation.gov.uk/ukpga/2005/5/section/797",
+        "https://www.legislation.gov.uk/ukpga/2005/5/section/783BB",
+    ]
+
+    def formula(person, period, parameters):
+        return person("rent_a_room_receipts", period) - person(
+            "rent_a_room_relief", period
+        )
diff --git a/policyengine_uk/variables/gov/hmrc/income_tax/total_income.py b/policyengine_uk/variables/gov/hmrc/income_tax/total_income.py
index f13a71fb4..a7daa17e7 100644
--- a/policyengine_uk/variables/gov/hmrc/income_tax/total_income.py
+++ b/policyengine_uk/variables/gov/hmrc/income_tax/total_income.py
@@ -18,6 +18,7 @@ class total_income(Variable):
         "social_security_income",
         "self_employment_income",
         "property_income",
+        "taxable_rent_a_room_income",
         "savings_interest_income",
         "dividend_income",
         "miscellaneous_income",
diff --git a/policyengine_uk/variables/gov/local_authorities/council_tax_reduction/council_tax_reduction_applicable_income.py b/policyengine_uk/variables/gov/local_authorities/council_tax_reduction/council_tax_reduction_applicable_income.py
index 53bba409a..dc402a4ac 100644
--- a/policyengine_uk/variables/gov/local_authorities/council_tax_reduction/council_tax_reduction_applicable_income.py
+++ b/policyengine_uk/variables/gov/local_authorities/council_tax_reduction/council_tax_reduction_applicable_income.py
@@ -1,6 +1,7 @@
 from policyengine_uk.model_api import *
 from policyengine_uk.variables.gov.local_authorities.council_tax_reduction.config import (
     is_scotland_scheme,
+    is_wales_scheme,
 )
 
 
@@ -113,9 +114,18 @@ def formula(benunit, period, parameters):
         p_scotland = parameters(
             period
         ).gov.local_authorities.scotland.council_tax_reduction.means_test
-        counts_home_letting = ~scottish_working_age_scheme | (
-            p_scotland.working_age_counts_home_letting_income
-        )
+        # Wales: for an applicant with an award of universal credit (who is
+        # never a pensioner, WSI 2013/3029 reg 3), income is the Secretary of
+        # State's universal credit assessment (Sch 6 para 9), which has no
+        # rent from part of the home. That route is otherwise not modelled
+        # here (#1966); this keeps such rent out of it.
+        wales_universal_credit_route = is_wales_scheme(
+            benunit.household("country", period)
+        ) & (add(benunit, period, ["universal_credit"]) > 0)
+        counts_home_letting = (
+            ~scottish_working_age_scheme
+            | p_scotland.working_age_counts_home_letting_income
+        ) & ~wales_universal_credit_route
         increased_income += where(
             counts_home_letting,
             benunit("legacy_benefits_home_letting_income", period),
@@ -136,6 +146,14 @@ def formula(benunit, period, parameters):
             ["legacy_means_test_income_tax", "national_insurance"],
             members,
         )
+        # Where the rent is not counted, neither is the tax on it.
+        tax -= where(
+            counts_home_letting,
+            0,
+            add_for_members(
+                benunit, period, ["rent_a_room_income_tax_after_reductions"], members
+            ),
+        )
         income_under_general_rules = max_(
             0, increased_income - tax - pension_contributions
         )
diff --git a/policyengine_uk/variables/gov/local_authorities/council_tax_reduction/council_tax_reduction_individual_non_dep_deduction_eligible.py b/policyengine_uk/variables/gov/local_authorities/council_tax_reduction/council_tax_reduction_individual_non_dep_deduction_eligible.py
index 36cb046b4..6323da1c4 100644
--- a/policyengine_uk/variables/gov/local_authorities/council_tax_reduction/council_tax_reduction_individual_non_dep_deduction_eligible.py
+++ b/policyengine_uk/variables/gov/local_authorities/council_tax_reduction/council_tax_reduction_individual_non_dep_deduction_eligible.py
@@ -6,8 +6,15 @@ class council_tax_reduction_individual_non_dep_deduction_eligible(Variable):
     entity = Person
     label = "eligible person for CTR non-dependent deduction"
     definition_period = YEAR
+    reference = "https://www.legislation.gov.uk/uksi/2012/2885/regulation/9"
 
     def formula(person, period, parameters):
-        return (person("age", period) >= 18) & ~person.benunit(
-            "benunit_contains_household_head", period
+        # A boarder or lodger is liable to pay the applicant on a commercial
+        # basis for their occupation, so is not a non-dependant (SI 2012/2885
+        # reg 9(2)(e)).
+        commercial = person("pays_rent_to_householder", period)
+        return (
+            (person("age", period) >= 18)
+            & ~person.benunit("benunit_contains_household_head", period)
+            & ~commercial
         )
diff --git a/policyengine_uk/variables/household/income/hbai_household_net_income.py b/policyengine_uk/variables/household/income/hbai_household_net_income.py
index 5061ab23c..5dfe28cbb 100644
--- a/policyengine_uk/variables/household/income/hbai_household_net_income.py
+++ b/policyengine_uk/variables/household/income/hbai_household_net_income.py
@@ -10,6 +10,7 @@
     "dividend_income",
     "miscellaneous_income",
     "property_income",
+    "sublet_income",
     "private_pension_income",
     "private_transfer_income",
     "maintenance_income",
diff --git a/policyengine_uk/variables/household/income/household_market_income.py b/policyengine_uk/variables/household/income/household_market_income.py
index 3991db6b7..e531eabd5 100644
--- a/policyengine_uk/variables/household/income/household_market_income.py
+++ b/policyengine_uk/variables/household/income/household_market_income.py
@@ -10,6 +10,7 @@
     "dividend_income",
     "miscellaneous_income",
     "property_income",
+    "sublet_income",
     "private_pension_income",
     "private_transfer_income",
     "maintenance_income",
diff --git a/policyengine_uk/variables/household/income/market_income.py b/policyengine_uk/variables/household/income/market_income.py
index 9df8de09c..0fbd44bb6 100644
--- a/policyengine_uk/variables/household/income/market_income.py
+++ b/policyengine_uk/variables/household/income/market_income.py
@@ -19,6 +19,7 @@ def formula(person, period, parameters):
             "dividend_income",
             "miscellaneous_income",
             "property_income",
+            "sublet_income",
             "private_pension_income",
             "private_transfer_income",
             "maintenance_income",
diff --git a/policyengine_uk/variables/household/income/pays_rent_to_householder.py b/policyengine_uk/variables/household/income/pays_rent_to_householder.py
new file mode 100644
index 000000000..75b47f92c
--- /dev/null
+++ b/policyengine_uk/variables/household/income/pays_rent_to_householder.py
@@ -0,0 +1,29 @@
+from policyengine_uk.model_api import *
+
+
+class pays_rent_to_householder(Variable):
+    value_type = bool
+    entity = Person
+    label = "in a family that pays the householder rent as boarders or lodgers"
+    documentation = (
+        "Whether this person's benefit unit, which does not contain the "
+        "household head, pays the household head rent for board and lodging "
+        "or for lodging. Such a person is liable to make payments on a "
+        "commercial basis for their occupation, so is not a non-dependant of "
+        "the householder. The model takes every such payment to be commercial "
+        "and the payer not to be a close relative living there, whom the "
+        "rules keep as a non-dependant (HB reg 3(3) with reg 9(1); CTR reg "
+        "9(3)). The Family Resources Survey asks about this rent only for "
+        "people not related to the household reference person."
+    )
+    definition_period = YEAR
+    reference = [
+        "https://www.legislation.gov.uk/uksi/2013/376/schedule/4/paragraph/9",
+        "https://www.legislation.gov.uk/uksi/2006/213/regulation/3",
+        "https://www.legislation.gov.uk/uksi/2012/2885/regulation/9",
+    ]
+
+    def formula(person, period, parameters):
+        paid = add(person, period, ["rent_paid_as_boarder", "rent_paid_as_lodger"])
+        in_head_benunit = person.benunit.any(person("is_household_head", period))
+        return person.benunit.any(paid > 0) & ~in_head_benunit
diff --git a/policyengine_uk/variables/household/income/rent_from_boarders_and_lodgers.py b/policyengine_uk/variables/household/income/rent_from_boarders_and_lodgers.py
new file mode 100644
index 000000000..e2aa086a3
--- /dev/null
+++ b/policyengine_uk/variables/household/income/rent_from_boarders_and_lodgers.py
@@ -0,0 +1,28 @@
+from policyengine_uk.model_api import *
+
+
+class rent_from_boarders_and_lodgers(Variable):
+    value_type = float
+    entity = Person
+    label = "rent received from boarders and lodgers"
+    documentation = (
+        "Rent the household head receives from boarders and lodgers: the "
+        "rent paid as a boarder or lodger by household members outside the "
+        "head's benefit unit, shared equally where more than one person is "
+        "flagged as household head (the survey data have one; with more, the "
+        "means tests share the rent after the disregards, not before). The "
+        "Family Resources Survey records this rent only on the payer. It is a transfer within the household, so "
+        "household income measures do not include it; it enters income tax "
+        "as rent-a-room receipts and the legacy means tests through the "
+        "home-letting income."
+    )
+    definition_period = YEAR
+    unit = GBP
+
+    def formula(person, period, parameters):
+        paid = add(person, period, ["rent_paid_as_boarder", "rent_paid_as_lodger"])
+        head = person("is_household_head", period)
+        in_head_benunit = person.benunit.any(head)
+        paid_to_head = person.household.sum(paid * ~in_head_benunit)
+        heads = person.household.sum(head)
+        return where(head, paid_to_head / max_(heads, 1), 0)
diff --git a/policyengine_uk/variables/input/rent_paid_as_boarder.py b/policyengine_uk/variables/input/rent_paid_as_boarder.py
new file mode 100644
index 000000000..92ffc11cf
--- /dev/null
+++ b/policyengine_uk/variables/input/rent_paid_as_boarder.py
@@ -0,0 +1,18 @@
+from policyengine_uk.model_api import *
+
+
+class rent_paid_as_boarder(Variable):
+    value_type = float
+    entity = Person
+    label = "rent paid to the householder as a boarder"
+    documentation = (
+        "Rent this person pays the householder for board and lodging (a room "
+        "and at least some meals) in the householder's home, where this "
+        "person lives as a member of the household outside the householder's "
+        "benefit unit. The Family Resources Survey records it on the payer "
+        "(CVPAY where CONVBL is 1). Annual amount; the weekly means-test "
+        "rules divide it by 52."
+    )
+    definition_period = YEAR
+    unit = GBP
+    uprating = "gov.economic_assumptions.indices.obr.per_capita.gdp"
diff --git a/policyengine_uk/variables/input/rent_paid_as_lodger.py b/policyengine_uk/variables/input/rent_paid_as_lodger.py
new file mode 100644
index 000000000..0859f6b9f
--- /dev/null
+++ b/policyengine_uk/variables/input/rent_paid_as_lodger.py
@@ -0,0 +1,17 @@
+from policyengine_uk.model_api import *
+
+
+class rent_paid_as_lodger(Variable):
+    value_type = float
+    entity = Person
+    label = "rent paid to the householder as a lodger"
+    documentation = (
+        "Rent this person pays the householder for lodging without meals in "
+        "the householder's home, where this person lives as a member of the "
+        "household outside the householder's benefit unit. The Family "
+        "Resources Survey records it on the payer (CVPAY where CONVBL is not "
+        "1). Annual amount; the weekly means-test rules divide it by 52."
+    )
+    definition_period = YEAR
+    unit = GBP
+    uprating = "gov.economic_assumptions.indices.obr.per_capita.gdp"
diff --git a/policyengine_uk/variables/input/sublet_income.py b/policyengine_uk/variables/input/sublet_income.py
index f1e600600..daaad5ce3 100644
--- a/policyengine_uk/variables/input/sublet_income.py
+++ b/policyengine_uk/variables/input/sublet_income.py
@@ -5,7 +5,14 @@ class sublet_income(Variable):
     value_type = float
     entity = Person
     label = "sublet income"
-    documentation = "Income from subletting properties"
+    documentation = (
+        "Rent this person receives for letting part of the home they live in "
+        "to someone who is not a member of the household. Income tax treats "
+        "it as rent-a-room receipts, and the legacy means tests count it less "
+        "a weekly disregard. Rent from other property is property_income; "
+        "rent from boarders and lodgers who live in the household is "
+        "rent_from_boarders_and_lodgers."
+    )
     definition_period = YEAR
     unit = GBP
     uprating = "gov.economic_assumptions.indices.obr.per_capita.gdp"