Council tax reduction for dementia comes mainly through the “severe mental impairment” rules. If a doctor confirms that your parent’s dementia severely and permanently affects their thinking and social functioning, and they get a qualifying benefit such as Attendance Allowance, they are ignored when the council counts adults in the home. If they live alone, the bill can drop to nothing. If they live with one other adult, it usually falls by 25%.
It is one of the most under-claimed reductions there is, partly because the phrase “severely mentally impaired” puts families off. It is a legal label, nothing more, and it covers dementia and Alzheimer’s disease. This guide explains who qualifies and how to apply to Adur & Worthing Councils, Arun District Council or Horsham District Council.
In short: a GP certificate plus a qualifying benefit such as Attendance Allowance equals a discount or full exemption. Apply to the district or borough council that sends the Council Tax bill, and ask for it from the date your parent first met the conditions.
Council tax reduction for dementia: who counts as severely mentally impaired?
The legal definition is someone with “a severe impairment of intelligence and social functioning (however caused) which appears to be permanent”. Councils in West Sussex give examples including dementia, Alzheimer’s disease, Parkinson’s disease, the effects of a stroke, severe or chronic mental illness and severe learning disabilities.
Two conditions must both be met:
- A doctor’s certificate. A registered medical practitioner, usually the GP, must confirm the impairment is severe and appears permanent.
- A qualifying benefit. The person must be entitled to one of a list of benefits.
Which benefits qualify?
The lists published by Adur & Worthing and Horsham include:
- Attendance Allowance
- Personal Independence Payment daily living component
- Disability Living Allowance care component at the middle or highest rate
- Employment and Support Allowance or Incapacity Benefit
- Universal Credit with limited capability for work
- Severe Disablement Allowance, and certain industrial injuries and war pension allowances
For most older people, the qualifying benefit will be Attendance Allowance. If your parent has dementia but has not claimed it, do that first. It is not means-tested and many people with dementia qualify. See our Attendance Allowance guide and the practical walkthrough on how to fill in the Attendance Allowance form.
Exemption or discount: what your parent’s household gets
Council Tax assumes two adults live in a home. A person who is severely mentally impaired is “disregarded”, meaning they are not counted. What that does to the bill depends on who else lives there.
| Household | Effect | Typical result |
|---|---|---|
| Your parent lives alone and qualifies | Exemption | No Council Tax to pay |
| Everyone in the home qualifies (for example, both parents have dementia) | Exemption | No Council Tax to pay |
| Your parent qualifies and lives with one other adult, such as a spouse | Disregard: the other adult is treated as living alone | 25% single person discount |
| Your parent qualifies and lives with two or more other adults | Disregard, but two adults still counted | Usually no change, unless others are also disregarded |
So the common situation, a husband caring for a wife with dementia, usually leads to a 25% discount. If he already gets the single person discount for another reason, nothing extra applies.
The difference between a “single occupant exemption” and a “disregard” confuses many people. Put simply, the exemption applies when nobody liable to pay is left once the qualifying person is ignored. The disregard applies when someone else still lives there and is billed as if they lived alone.
How to apply in Worthing, Adur, Arun and Horsham
Council Tax is run by the district or borough council, not by West Sussex County Council. Apply to whichever council sends your parent’s bill.
Adur & Worthing Councils
Adur & Worthing Councils have an online application for the severe mental impairment discount or exemption, with separate routes for Adur and for Worthing addresses. You will need the Council Tax account reference. They also publish a paper form with a section for the doctor to complete; this goes to Revenues & Benefits, PO Box 5000, Worthing BN11 1JN. Apply through the Adur & Worthing discounts and exemptions page.
Arun District Council (Littlehampton, Rustington, Bognor Regis)
Arun asks you to apply through its online Council Tax portal (see Arun’s severe mental impairment page), selecting the severe mental impairment discount and uploading two documents: a certificate signed by a GP confirming the condition is permanent and severely affects thinking and social functioning, and proof of the benefit award showing the start date.
Horsham District Council (including Steyning and Henfield)
Horsham publishes a form in two parts. You complete part one with household details and the date from which you want the discount. Part two goes to the GP, who completes the medical certificate. Send it with proof of the qualifying benefit; Horsham’s form says applications without sufficient proof cannot be processed.
Getting the GP certificate
Book a routine appointment or send a request through the practice. Take the council’s form with you. Some GP practices charge for completing non-NHS forms, so ask first. If your parent is under a memory clinic or older people’s mental health team, the consultant may also be able to confirm the diagnosis.
Can the discount be backdated?
Usually, yes. The discount or exemption applies from the date your parent met both conditions: the date the impairment was present and the qualifying benefit was in payment. On the application, give the earliest date you believe applies, typically the start date of the Attendance Allowance award, and send the award letter as proof.
Families sometimes discover years later that they have been paying full Council Tax for a parent who qualified. It is worth asking the council to review the whole period and refund any overpayment. If the council refuses, you can ask for the decision to be reviewed and then appeal to the Valuation Tribunal.
What if your parent moves into a care home or hospital?
If your parent has moved permanently into a care home or is in hospital long term, their former home may be exempt while it is empty. Tell the council straight away. If a spouse remains at home alone, they should be entitled to a single person discount.
Other Council Tax help worth checking
Council Tax Reduction (Council Tax Support)
This is the means-tested scheme for people on a low income. Adur & Worthing and Horsham call it Council Tax Support. Each council runs its own scheme, but pensioners are assessed under rules set nationally. People getting the Guarantee Credit part of Pension Credit usually get the most help. Attendance Allowance can increase Pension Credit through its severe disability amount, which can then increase Council Tax help. Apply on your council’s website.
Disabled band reduction
Under the Disabled Band Reduction Scheme, if the home has an extra bathroom, kitchen or other room needed by a disabled person, or extra space for using a wheelchair indoors, the bill can be charged one band lower. Homes already in Band A get a 17% discount instead. This is separate from the severe mental impairment rules, and both can apply at once. If you have made home adaptations for disability, check this too.
Carers
Some live-in carers can also be disregarded for Council Tax, for example someone providing at least 35 hours of care a week to a person who is not their partner and who gets a qualifying benefit. Ask the council, and see our Carer’s Allowance guide for the benefits side.
Council Tax is only one part of the money picture. Our free funding checker shows what other help your parent may be missing, and our guide to dementia care at home covers the support that helps people stay in their own home.
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Frequently asked questions
Is dementia classed as severe mental impairment for council tax?
It can be. Dementia and Alzheimer’s disease are among the conditions councils list, but the GP must confirm the impairment is severe and appears permanent. Early-stage dementia may not meet the test yet, so reapply if things change.
Does my mum need Attendance Allowance to get the council tax discount?
She needs one of the qualifying benefits, and for most people over State Pension age that is Attendance Allowance. Claim it first; once awarded, you can apply to the council and ask for the discount from the start date of the award.
Can I get a council tax reduction if my husband has dementia?
If he qualifies and you are the only other adult, you are treated as living alone and should get a 25% discount. If you are on a low income you may also get Council Tax Reduction on top.
How far back can a council tax dementia discount be backdated?
Councils normally backdate to the date both conditions were first met. Give the earliest date and supporting evidence on the application, and ask the council to refund any overpayment.
Does the GP charge for the council tax certificate?
Some practices charge for forms that are not part of NHS services. Ask the surgery before you book, and take the council’s form with you.
The Care Panel is an independent publication. We are not a care provider and are not regulated by the Care Quality Commission, because we do not deliver care. Always check a provider’s own CQC registration and inspection report before you commit.
Written and fact-checked by The Care Panel. Last updated September 2026. Sources: GOV.UK Council Tax discounts for disabled people, Adur & Worthing Councils, Arun District Council, Horsham District Council. General information, not financial, legal or medical advice — figures are indicative and subject to change.