Last reviewed: 30 April 2026 | Sources: GOV.UK, Valuation Office (formerly VOA, now part of HMRC since 1 April 2026), Local Government Finance Act 1992
⚡ TL;DR — Skip to what matters
Two separate council tax reliefs apply to people with disabilities or severe mental impairment. First, the Severely Mentally Impaired (SMI) disregard: an SMI person is completely invisible when councils count adults — a sole SMI occupant pays nothing; if one of two adults has SMI, the other gets the 25% single person discount. Second, the disability reduction: if your home has been adapted with specific features for a disabled resident, your council tax band is reduced by one band (Band A properties get a 1/9th reduction). Both must be actively claimed.
📋 Key Facts at a Glance
- SMI disregard: person must have a severe, permanent impairment of intelligence/social functioning from brain disorder AND be in receipt of a qualifying benefit
- Qualifying benefits for SMI: Incapacity Benefit, ESA, Universal Credit (limited capability), PIP (enhanced daily living), Attendance Allowance, DLA (highest care rate), Severe Disablement Allowance, Disability Working Allowance, others
- SMI sole occupant: property 50% discount (not fully exempt — but Council Tax Reduction may reduce bill to zero)
- SMI + 1 other adult: other adult gets 25% SPD as sole non-disregarded person
- Disability reduction: band reduced by one (e.g. Band D → Band C) for adapted homes
- Adapted property features: room for wheelchair use, extra bathroom/kitchen, specially adapted room for dialysis/other treatment
- Disability reduction: apply to your local council — not automatic
- Source: GOV.UK — Council Tax: disabled people | Local Government Finance Act 1992
The Severely Mentally Impaired (SMI) disregard
Under the Council Tax (Discount Disregards) Order 1992, a person is "severely mentally impaired" for council tax purposes if they have a severe impairment of intelligence and social functioning that results from a condition that causes brain damage (whether progressive or not) and that impairment appears to be permanent.
The definition is legal, not medical — it is broader than many people assume. It can include people with dementia, stroke-acquired brain injury, severe learning disabilities, Parkinson's disease (in advanced stages), Huntington's disease, and other conditions. However, it must be:
- Permanent — not a temporary condition
- Certified — a registered medical practitioner must confirm the condition in writing
- Linked to a qualifying benefit — the person must be in receipt of at least one of the qualifying benefits (see Key Facts above)
All three conditions must be met. A person with a severe mental health condition who does not receive a qualifying benefit does not qualify for the SMI disregard — they may still qualify for Council Tax Reduction (means-tested) if their income is low.
How the SMI disregard affects your bill
| Household composition | Council tax outcome |
|---|---|
| Only resident is SMI | 50% discount (property is not "fully exempt" but a 50% discount applies as if all residents are disregarded — further reduced to zero by CTR in many cases) |
| SMI person + 1 non-SMI adult | Non-SMI adult is sole non-disregarded adult — 25% single person discount applies |
| SMI person + 2 non-SMI adults | No discount — two non-disregarded adults |
| 2 SMI people + 1 non-SMI adult | Non-SMI adult is sole non-disregarded adult — 25% SPD applies |
| All residents SMI | 50% discount on each SMI person's proportion — effectively 50% total reduction |
How to claim the SMI disregard
- Obtain written confirmation from a registered medical practitioner (GP or specialist) that the person has a permanent severe impairment of intelligence and social functioning resulting from a brain disorder
- Gather evidence of a qualifying benefit (benefit award letter showing current entitlement)
- Contact your local council's council tax department — most have a specific SMI discount application form
- Submit both pieces of evidence — the medical confirmation and the benefit evidence
- The council will process your application and issue an amended bill
The disregard applies from the date the conditions are met — not just from the date of application. If a person has been severely mentally impaired and in receipt of a qualifying benefit for several years but has never claimed the disregard, you may be able to claim a backdated refund. Ask your council about their backdating policy.
The disability reduction: band reduction for adapted homes
Separate from the SMI disregard, the disability reduction applies to homes that have been adapted for a disabled resident. It reduces your council tax band by one band — so a Band D property pays Band C rates, a Band C property pays Band B rates, and so on. Band A properties receive a one-ninth reduction below the Band A charge (since there is no Band below A).
Your home qualifies for the disability reduction if it has at least one of the following features used by and essential to the disabled resident:
- A room (other than a bathroom, kitchen or toilet) used predominantly for meeting the needs of the disabled person — for example, a downstairs bedroom or a dialysis room
- An additional bathroom or kitchen specifically for the disabled person's use
- Sufficient floor space to allow use of a wheelchair indoors
The reduction is not automatic — you must apply to your local council. Most councils have a specific disability reduction application form. You will need to describe the adaptations and confirm they are essential to and primarily used by the disabled resident.
Interaction with Council Tax Reduction (CTR)
Council Tax Reduction is a separate means-tested scheme administered by each council for residents on low incomes. It can reduce your bill by up to 100% in some council schemes. The SMI disregard and disability reduction can apply alongside CTR — they are not mutually exclusive. In practice, many households with severely mentally impaired members who are sole occupants combine the 50% SMI discount with CTR to achieve a zero or near-zero council tax bill.
Frequently asked questions
Does dementia automatically qualify as SMI?
Not automatically — dementia must be confirmed by a registered medical practitioner as causing a permanent severe impairment of intelligence and social functioning, and the person must receive a qualifying benefit. In practice, most people with a formal dementia diagnosis who receive PIP (enhanced daily living), Attendance Allowance or ESA will qualify. Confirm with your council.
Can I claim both the SMI disregard and the disability reduction?
Yes, if you qualify for both. The SMI disregard reduces the number of liable adults, potentially creating a 25% or 50% discount. The disability reduction separately lowers your band by one. Both operate on different parts of the calculation and can apply simultaneously.
My partner has a mental health condition but is not in receipt of any benefits — do we qualify?
Not for the SMI disregard, unless your partner is in receipt of one of the qualifying benefits. However, if their income is low, they may qualify for Council Tax Reduction through your local council's means-tested scheme, which does not require benefit receipt in the same way.
How long does the disability reduction last?
The disability reduction continues as long as the qualifying conditions are met — the disabled person continues to live in the property and the adapted features remain in use. Notify your council if the disabled resident moves out or the adaptations are removed.
Where can I get help claiming these discounts?
Citizens Advice offers free, confidential support for council tax queries. Most councils also have a welfare team that can help. For carers and people supporting someone with a disability, Carers UK (carersuk.org) provides guidance on the full range of financial support available.
Sources & References
- GOV.UK — Council Tax: disabled people: gov.uk/council-tax/discounts-for-disabled-people
- Local Government Finance Act 1992, Section 11 — disability reduction
- Council Tax (Discount Disregards) Order 1992 — SMI disregard
- Council Tax (Reductions for Disabilities) Regulations 1992 (SI 1992/554)
- Citizens Advice — Council tax discounts for disabled people
- Carers UK — carersuk.org
Disclaimer: This article is for informational purposes only and does not constitute financial, legal or tax advice. Always verify at GOV.UK before acting. For more guides visit our UK Council Tax hub.
