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Downstairs toilet cost: what it really costs in 2026
The small job that adds real value.
£2,500 – £5,500
Adding a downstairs WC starts around £2,500 basic, £3,750 mid-spec, and £5,500 premium — assuming an existing space like under the stairs.
Price by spec
| Option | What it means | Typical price |
|---|---|---|
| Basic | Standard suite in an existing space | £2,500 – £3,000 |
| Mid-spec | Better fittings and tiling | £3,750 |
| Premium | High-end suite and finishes | £5,500 |
What actually happens
- Space surveyed — drainage route is the deciding factor
- Stud walls or door moved if needed
- Soil pipe and water supply connected
- Ventilation installed (required with no window)
- Suite fitted; walls boarded and decorated
- Flooring, lighting and final fix
Popular choices
Under-stairs conversionsCompact cloakroom suitesBold wallpaper and dark paint — small rooms can be brave
Regulations to know
- Building regulations apply — drainage, and ventilation if there's no opening window
- New electrics in there are notifiable under Part P
- No planning permission needed inside your own house
Tips from the trade
- Distance to the soil stack drives the price more than the suite does
- A macerator makes awkward locations possible — but gravity drainage is always better if you can get it
Plan this project properly
Get a region-adjusted estimate, track budget against real quotes, and find local tradespeople -- free to browse on Qome.
Start planning on QomePrices on this page are approximate, region-adjusted guide figures built from cross-checked UK cost data. They exist to inform you, not to bind anyone. Actual prices are whatever you and your tradesperson agree, and a difference between a Qome guide figure and a real quote is not a fault in either.