Typical costs
Many cloakroom projects fall somewhere in the ranges below. The biggest variable is drainage: a toilet near an existing soil stack or drain is far cheaper than one that needs a long new run or a pumped system.
| Part of the job | Typical price |
|---|---|
| Plumbing and drainage connection (straightforward) | £1,000–£2,000 |
| Plumbing with a long or difficult drain run | £2,000–£3,500 |
| Macerator WC installation (where suitable) | £600–£1,200 plus the unit |
| Complete under-stairs cloakroom, all trades | £2,500–£6,000 |
Indicative UK prices. They vary with location, access and the condition of the existing plumbing – always compare written quotes for your own job.
Drainage is the key question
A toilet needs a 110mm soil pipe with a steady fall to the drain. If the new WC can connect to an existing soil stack or underground drain nearby, the job is straightforward. If it's at the front of the house and the drains are at the back, the plumber may need to run pipe under the floor, through walls or outside – or use a macerator.
Macerator toilets pump waste through a small pipe and can make awkward locations possible, but Building Regulations guidance generally expects them to be in addition to a conventionally drained toilet in the home, and they need regular care.
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Regulations to be aware of
Adding a WC usually involves Building Regulations for drainage and ventilation, and sometimes building control approval. A WC needs adequate ventilation – an extractor fan or an openable window – and hand-washing facilities in or next to it. It shouldn't open directly into a room used for preparing food. Your plumber or builder should advise.
Other costs
- Stud walls, a door and making good
- Electrics for lighting and an extractor fan
- Flooring and tiling
- The toilet, compact basin, tap and accessories
- Building control fees where applicable
