Annexe Council Tax Discount 2026 - 50% Off or Full Exemption
If your property has a separately banded annexe — often called a granny flat — there are three different council tax rules that could apply. The right rule depends on who lives in the annexe and whether a planning restriction prevents it being let separately. In the best cases, the annexe pays nothing at all. Updated May 2026.
50% reduction
Half off
family member occupier — SI 2013/2977
100% exemption
£0
Class T (planning restriction) or Class W (elderly/disabled relative)
Apply through
Your local council
Evidence: family relationship, planning docs, or medical proof
Three Rules — Which One Applies?
Annexe council tax relief is not a single rule — it is three separate provisions, each with its own qualifying test. The table below summarises them. Only one rule can apply at any time; use whichever gives the greatest reduction.
| Rule | Legislation | Reduction | Key condition |
|---|---|---|---|
| 50% reduction | SI 2013/2977 | 50% off annexe bill | Annexe occupied by a qualifying relative of the main-dwelling liable person, or used as part of the main household |
| Class T exemption | SI 1992/558, Class T | 100% exempt — £0 | Annexe is unoccupied and a planning condition prevents it being let separately |
| Class W exemption | SI 1992/558, Class W | 100% exempt — £0 | Annexe occupied as sole or main residence of a dependent relative (aged 65+, disabled, or severely mentally impaired) |
Sources: legislation.gov.uk — SI 2013/2977 | GOV.UK granny flat announcement
Eligibility — What Counts as an 'Annexe'?
For any of the three rules to apply, the annexe must already be a separately banded dwelling — meaning the Valuation Office Agency (VOA) has assigned it its own council tax band distinct from the main property. A room, extension or converted garage that shares a band with the main house is not treated as a separate dwelling and carries no separate council tax charge, so no annexe discount is needed or possible.
In practice, a separately banded annexe is typically self-contained: it has its own kitchen, bathroom and sleeping area with an independent entrance. However, the discount test is about the banding and the occupier relationship, not about the physical specification in isolation. If the VOA has banded it separately, the three rules can apply.
If you believe your annexe has been given a separate band when it should not have been — or has not been banded when it should be — you can challenge the band via the banding challenge process. Getting the banding right is the first step before applying for any annexe discount.
Worked Examples
50% reduction (SI 2013/2977)
Son lives in Band A annexe
Class W exemption
Owner's 70-year-old mother lives in annexe
Class T exemption
Annexe unoccupied — planning condition prevents separate let
Examples use a Band A annexe at £1,333/yr. Your figure will differ depending on your council and band.
How to Apply
None of the three annexe rules are applied automatically. You must contact your local council's council tax team and make a claim. Most councils accept applications online or by post. Search for '[your council] annexe council tax discount' to find the specific form.
The evidence you will need depends on which rule you are claiming:
- •50% reduction (SI 2013/2977): proof of family relationship (birth or marriage certificate), confirmation the annexe is occupied by the relative or used as part of the main household.
- •Class T exemption: a copy of the planning permission or planning condition document that restricts the annexe from being let separately.
- •Class W exemption: proof of family relationship, plus evidence of the dependent relative's age (65+), disability, or severe mental impairment — typically a GP letter and a qualifying benefit award letter.
The council may send an officer to confirm the annexe is separately banded and that the qualifying conditions are met. Ask specifically for backdating to the date the conditions first applied — there is no statutory time limit preventing a backdate.
Common Pitfalls
Paying full council tax without realising a discount applies
Many annexes are billed as completely separate dwellings at the full rate, with no discount applied, simply because the owner never claimed. If a relative has lived in your annexe for years, review your band records and apply retrospectively. The potential refund can run to several years of overpaid tax.
Assuming cousins are qualifying relatives
The relative list under SI 2013/2977 does not include cousins. Spouse, civil partner, parent, grandparent, child, grandchild, sibling, step-relations, aunt, uncle, nephew and niece all qualify. Cousins do not. This is a common misreading of the regulations.
Missing the stacking opportunity
The 50% annexe reduction can stack with a single-person discount if the annexe occupant lives alone and is the only non-disregarded adult. Some councils do not flag this automatically. The 50% reduction applies first; if the annexe occupant also qualifies for a single-person discount, the two are applied in combination.
Not applying Class T when the annexe stands empty
Owners sometimes accept full council tax on an empty annexe without checking whether a planning condition prevents separate letting. If a planning condition ties the annexe to the main dwelling, the annexe is Class T exempt while unoccupied. Check your original planning permission.
Losing the second-home premium exemption
From April 2025 the second-home premium exceptions (SI 2024/1007, Class F) explicitly shield annexes used as part of the main residence from the second-home premium. If your council is charging a second-home premium on your annexe and it meets the Class F condition, you should be exempt from that premium as well.
Frequently Asked Questions
What is the 50% annexe discount and who qualifies?
What is the Class T exemption and when does it apply?
What is the Class W exemption and who is a 'dependent relative'?
Can the annexe discount be backdated?
What counts as an annexe for council tax purposes?
Where to Read Next
Updated May 2026. Rules set by the Council Tax (Reductions for Annexes) (England) Regulations 2013 (SI 2013/2977) and the Council Tax (Exempt Dwellings) Order 1992 (SI 1992/558).
Founder of Digital Signet, an independent research firm publishing data-led pricing and decision tools. CouncilTaxBands.com rates are sourced from individual council websites, GOV.UK, ONS, and the Valuation Office Agency. Always confirm the current band and rate with your local authority.