Council Tax SMI Discount: Household Scenarios Explained
The Discount Depends on Who Lives in the Property
The SMI disregard removes a qualifying person from the household headcount for council tax purposes. But the financial outcome — whether the bill falls by 25%, 50%, or 100% — depends entirely on who else lives in the property. This is where most families get confused.
Scenario 1: Living Alone
A person with dementia who lives alone and qualifies as SMI is disregarded from the headcount. The household drops to zero counted adults. The property qualifies for a Class U exemption under The Council Tax (Exempt Dwellings) Order 1992. The council tax bill is £0 — a full 100% reduction.
This is the highest-value scenario and one of the most under-claimed. An elderly widow or widower with dementia who receives Attendance Allowance may have been paying the full council tax bill (with or without the standard 25% single person discount) for years when they should have been paying nothing.
Scenario 2: Couple — One Person Has Dementia
A married couple or cohabiting partners where one person qualifies as SMI and the other is a non-disregarded adult. The SMI person is removed from the headcount, leaving one counted adult. The household gets a 25% single person discount.
A critical point: the spouse or partner does not qualify for a carer disregard simply because they provide care. Under Schedule 1 of the LGFA 1992, the carer disregard is only available to non-spousal, non-partner carers who provide at least 35 hours of care per week to someone in the same household. A husband caring for his wife with dementia does not get an additional discount through the carer route. The SMI disregard giving the 25% reduction is the maximum relief available in this household configuration.
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Scenario 3: Two People, Both Qualifying as SMI
If both adults in a household qualify as severely mentally impaired — for example, an elderly couple both with advanced dementia — both are disregarded. The headcount drops to zero and the property qualifies for a Class U exemption: £0 council tax.
Scenario 4: SMI Person Plus a Full-Time Student
If the only other person in the household is a full-time student (who is also disregarded under different rules), the headcount drops to zero. Class U exemption applies — £0 bill. This can arise when an adult child who is a university student lives with a parent who has SMI.
Scenario 5: SMI Person Plus a Non-Spousal Live-in Carer
A non-spousal carer — an adult child, sibling, or friend — who provides at least 35 hours per week of care to someone in the household and is not the spouse or partner of the person they care for can qualify for a separate carer disregard. If both the SMI person and the carer are disregarded, the headcount drops to zero and a 50% disregard discount applies.
However, the carer disregard has its own qualifying conditions. The carer must live in the same property and provide at least 35 hours of care per week. The person being cared for must receive the middle or highest rate of the DLA care component, either rate of Attendance Allowance, or the daily living component of PIP. The carer cannot be the spouse or partner of the person being cared for, and cannot be a parent of a child under 18 in the household. This is a separate claim from the SMI disregard.
Scenario 6: SMI Person Plus Two or More Other Adults
If a person with SMI lives with two or more other non-disregarded adults — for example, a parent with dementia living with a spouse and an adult child — the SMI person is disregarded, but two adults remain. The standard headcount rules mean no occupancy discount applies. The full council tax bill is payable by the remaining adults. The SMI person, however, is protected from personal joint and several liability.
The SMI Disregard vs the Carer Disregard
These are two completely different reliefs that people frequently confuse:
| SMI Disregard | Carer Disregard | |
|---|---|---|
| Who is disregarded | The person with the impairment | The person providing care |
| Medical requirement | GP-certified severe mental impairment | The care recipient receives qualifying benefit |
| Benefit requirement | SMI person entitled to qualifying benefit | Carer provides 35+ hours/week |
| Spouse eligible? | Yes — the SMI person is disregarded | No — spouses and partners are excluded |
A household can have both disregards active at the same time. If a non-spousal carer living in the property qualifies for the carer disregard and the person they care for qualifies for the SMI disregard, both are removed from the headcount.
Working Out Your Household's Position
Count the adults in the property. Remove anyone who qualifies for a disregard — SMI, carer, full-time student, or any other statutory disregard. The number remaining determines the discount: zero counted adults = 50% discount unless the occupants qualify for Class U exemption (£0), one adult = 25% discount, two or more = full bill.
For a detailed household composition worksheet and the full claim process, see our Severe Mental Impairment Council Tax Exemption Guide.
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