Severe Mental Impairment Council Tax Exemption in Dorset

What Severe Mental Impairment Means for Council Tax

Severe Mental Impairment (SMI) is a legal term, not a medical diagnosis. Under council tax law, a person is classified as severely mentally impaired if a registered medical practitioner certifies that they have a severe impairment of intelligence and social functioning (however caused) that appears to be permanent, and they are entitled to at least one qualifying benefit.

Common conditions that lead to an SMI certification include dementia (all types), severe learning disabilities, brain injuries resulting in permanent cognitive impairment, and advanced Parkinson's disease. The key is the functional impact — a permanent and severe loss of the ability to manage daily tasks and social interactions.

Qualifying Benefits

The person must also be entitled to a qualifying disability benefit. Dorset Council guidance names examples including:

• Personal Independence Payment (PIP) — daily living component
• Attendance Allowance

Check with Dorset Council which other benefits qualify and what evidence it requires. A pending benefit claim does not by itself confirm entitlement for the SMI disregard.

Two Possible Outcomes

Class U Exemption (100% off): If the person with SMI lives alone, the property is exempt from council tax entirely. No bill at all.

Single Person Discount (25% off): If the SMI person lives with one other adult, the SMI person is disregarded from the adult count, which means only one "counted" adult lives in the property. That triggers the standard 25% Single Person Discount.

In a household with multiple adults where one has SMI, the disregard reduces the counted adults by one but may not trigger the SPD if other non-disregarded adults remain.

How to Apply in Dorset

Contact Dorset Council's Benefits team at 01305 211930 or email [email protected]. You will need:

1. Medical certificate — a letter from the person's GP or hospital consultant confirming severe impairment of intelligence and social functioning that appears permanent. Some councils have a specific form; ask Dorset Council whether they require their own template or accept a GP letter.
2. Proof of qualifying benefit — an award letter showing current entitlement to a benefit Dorset Council accepts for the SMI disregard, such as PIP daily living or Attendance Allowance.
3. Council tax account details — the account number and property address.

If you think the qualifying conditions were met earlier, ask Dorset Council whether it can apply the disregard retrospectively and what evidence and date rules apply. Do not assume that the working-age CTR backdating limit also sets the dates for an SMI disregard.

SMI and Council Tax Reduction Together

If the SMI person lives with a partner or other adults and the household also qualifies for Council Tax Reduction, the SMI disregard is applied first in the discount stacking order. This means:

1. SMI disregard removes the person from the headcount
2. If that triggers SPD, the bill drops by 25%
3. Council Tax Reduction is then calculated on the lower figure

A couple where one person has SMI and receives PIP, with the other person working part-time, benefits from the SMI person being disregarded (triggering the 25% SPD), plus full exclusion of PIP from the income assessment, plus the £50 weekly disability disregard on the working partner's earnings. The combined effect often pushes the household into Band 1 (100% CTR discount) on a bill that is already 25% lower.

Common Mistakes

• Not claiming because the person "still lives at home." The SMI disregard applies wherever the person lives — it removes them from the count, it does not require them to live alone.
• Waiting for a formal diagnosis. The GP or consultant certificate is what matters, not a specific named diagnosis. If the doctor is willing to certify permanent severe impairment of intelligence and social functioning, that is sufficient.
• Not claiming retrospectively. If the conditions were met in previous years, ask about backdating to the date SMI and the qualifying benefit overlapped.

The Dorset Council Tax Reduction guide covers how the SMI disregard interacts with the income-banded CTR system, including worked scenarios for mixed-age couples and households with multiple disregarded adults.

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