The method
The Valuation Office will use the comparable sales method, the same basic approach used for council tax: what would this home have sold for in 2026, judged against sales of similar homes? The consultation describes a model-assisted approach. Automated valuation models do most of the work where there is plenty of sales evidence, and valuers apply more judgement where homes are unusual or sales are thin.
The information it will use
- sales prices, including Land Registry and Stamp Duty Land Tax records
- what it already holds about each home: type, size, age, number of rooms and parking
- planning records and local authority information
- mapping and geospatial data
Where records are thin or a home is unusual, the Valuation Office may contact the owner to check or clarify details. Home visits are expected to be a last resort and only with the owner's agreement.
The timetable
- 2026The valuation year. Homes are valued as they stood, and as the market was, in 2026.
- Late 2027The Valuation Office publishes a draft list of homes in scope, so councils can prepare bills. Owners can ask it to correct factual mistakes without a formal challenge.
- March 2028Councils issue the first bills.
- From 2028An initial 8-month window to challenge a band, then the right to appeal to the Valuation Tribunal for England. See challenges and appeals.
- 2033The first revaluation. The government proposes one every five years.
Where valuations tend to go wrong
An automated model is only as good as its inputs and the sales it can compare against. The homes most at risk of a wrong band are the ones that do not look like their neighbours on paper.
Wrong facts
Floor area is the classic error: measured wrongly, counted on the wrong basis, or including space that is not really usable, such as low loft rooms or unconverted basements. Room counts, parking and garden size can all be out of date too, especially after works or a change of layout.
Few true comparables
Large detached houses, one-off designs, listed buildings and homes on unusual plots often have no close match among recent sales. The further a valuer has to reach for evidence, the wider the margin of error.
Things a model cannot see
Structural problems, subsidence history, noise, poor access, overlooking, a short lease or rights of way all affect what a buyer would pay. None of them shows up in a sales database.
Blocks and conversions
Flats in the same block can differ a great deal by floor, outlook and condition. Houses split into flats, or flats merged back into houses, are easy for records to get wrong.
Worth doing now
Because the value is fixed at 2026, evidence of how the home was that year is the most useful thing you can hold. Photographs, a measured floor plan, any survey or defect reports, and a note of sales of similar homes nearby will all matter if you later need to challenge.
Our valuation review puts that evidence together with a qualified tax adviser and property surveyor, so it is ready before the draft list appears.
Valuation questions
Will someone from the Valuation Office visit my home?
Probably not. Visits are described as a last resort, made only with the owner's agreement, and usually where the owner has asked for one because more evidence is needed.
Is the mansion tax value the same as my council tax band?
No. Council tax bands in England still rest on 1991 values. The surcharge uses a separate valuation of each home as at 2026.
Can I see my valuation before I am billed?
The Valuation Office plans to publish a draft list of homes in scope in late 2027, before bills go out in March 2028. Owners will be able to ask it to correct factual mistakes at that stage.
Last checked against the government's Budget documents and consultation response on 30 October 2026. The surcharge is being legislated in the Finance Bill 2026-27 and is not yet law. Some detail is still to come in regulations.