Bathroom Plumbing Costs in London for 2025: A Realistic Breakdown by Fixture

Realistic Bathroom Plumbing Costs in London (2025)

Bathroom renovations are one of the most popular home improvements in London, and plumbing is typically the largest labour cost. Prices vary significantly by borough, job complexity, and property type, but this breakdown gives you a solid baseline for budgeting.

Cost by Fixture: What to Expect

Basin (Sink)

Supply and fit a new basin: £150–£300 for standard installations. Wall-hung basins with concealed waste add £50–£100 due to the additional pipework and structural fixing requirements. If the existing waste run needs extending or rerouting, add £80–£150.

WC (Toilet)

Supply and fit a close-coupled toilet: £200–£350. Back-to-wall or wall-hung WC units with concealed cisterns: £350–£600, as these require building a duct or frame, additional pipe concealment, and more complex servicing access. Replacing a like-for-like toilet on existing waste connections is the cheapest option at £150–£250 labour only.

Bath

Removing an old bath and fitting a new standard acrylic bath: £300–£500 labour. Freestanding baths cost more because the waste must be concealed in the floor or run under the bath, adding £100–£200. Cast iron baths require two-person installation; expect a surcharge of £50–£100.

Shower Enclosure and Tray

Supply and fit a shower tray, waste, and enclosure: £400–£800 depending on tray size and tile versus panel enclosure. Wet room conversions requiring tanking the entire floor area: £600–£1,200 for the plumbing and waterproofing element alone, before tiling.

Shower Valve

Fitting a thermostatic bar valve or concealed valve: £150–£300 labour. Concealed valves with body jets or multiple outlets require significant pipework and add £200–£400.

Hidden Costs That Catch People Out

• Waste rerouting: Victorian and Edwardian terraces often have cast iron soil stacks. Connecting new fixtures to these, or converting from lead or cast iron to PVC, adds £200–£500.
• Floor structure: If joists need notching or the subfloor requires strengthening for a heavy bath or wet room, structural work adds £300–£600.
• Mould and rot remediation: Found after stripping out, remediation behind tiles can cost £200–£500 before replastering.
• Water pressure: If your property has low mains pressure, a shower pump (£150–£300 supply and fit) may be needed for adequate shower performance.
• Gas works: If moving a heated towel rail from electric to a plumbed connection, a Gas Safe engineer is needed if it feeds off the heating circuit.

When to DIY Versus Call a Plumber

Certain tasks are legally or practically outside the sensible DIY range in London:

• Any gas works: Illegal without Gas Safe registration. Non-negotiable.
• Soil pipe connections: Errors cause persistent leaks, smells, and Building Regulations issues. Not worth DIY.
• First-fix pipework runs: Requires cutting into walls and floors. Mistakes are expensive to fix once boarded over.

Tasks where competent DIY can save money:

• Fitting taps to an already-plumbed basin or bath (after water is isolated).
• Replacing a cistern syphon or fill valve.
• Fitting a showerhead or replacing a shower hose.
• Re-sealing around a bath or shower tray.

Getting Accurate Quotes

Always get at least three quotes from Gas Safe and Chartered Institute of Plumbing-registered plumbers. Provide a full fixture list and ask for a fixed-price quote rather than day-rate. Day-rate work on bathroom projects regularly runs over budget when hidden issues arise. A fixed price puts the risk on the contractor, which is where it belongs.