How to Replace a Kitchen Tap – DIY Guide
To replace a kitchen tap, turn off the water supply, disconnect the old tap’s supply pipes and waste connections, remove the retaining nut beneath the sink, fit the new tap using the same fixings, reconnect the supply pipes and turn the water back on.
Disconnect the Supply Pipes
Place a bucket beneath the sink to catch any remaining water. Use an adjustable spanner to loosen the compression nuts connecting the flexible hoses to the tap tails — hold the hose body with slip-joint pliers to stop it spinning. Once disconnected, check the condition of the flexible hoses; if they are older than ten years or show any corrosion, replace them now alongside the tap. If you notice a slow drip from joints once the pressure is off, this could indicate wider issues — see our guide to fixing a dripping tap for context on common failure points.
Remove the Old Tap
Working from beneath the sink, use a basin wrench to reach up and loosen the back-nut securing the tap to the sink deck. This is usually the most awkward part of the job — a long-handled basin wrench makes it significantly easier than a standard spanner in the confined space. Once the nut is free, lift the old tap out from above. Clean away any old silicone or limescale residue from the sink deck with a utility knife and a damp cloth before fitting the new tap.
Fit the New Tap
Feed the tap tails through the sink hole from above, ensuring any supplied rubber gasket or sealing plate sits flat against the sink deck — if no gasket is provided, run a bead of silicone sealant around the base of the tap before lowering it in. From beneath the sink, slide on the top-hat washer and hand-tighten the back-nut. Use the basin wrench to tighten it firmly, but avoid over-tightening on a ceramic or thin stainless sink as this can crack the deck. If fitting a monobloc mixer, ensure the single central hole aligns correctly before tightening.
Reconnect the Supply Pipes
Wrap two to three layers of PTFE tape clockwise around the male threads of each tap tail before attaching the flexible connector hoses. Tighten the compression nuts with an adjustable spanner — firm hand-tight plus a quarter-turn is sufficient. Do not over-torque. If you need to fit a compression fitting to extend a short supply pipe to reach the new tap tails, ensure the olive seats squarely before tightening. Double-check you have connected hot to hot and cold to cold — the left tap tail is conventionally hot.
Test for Leaks and Check Flow
Slowly open the isolation valves or turn the stopcock back on. Allow the system to pressurise fully before opening the new tap. Run both hot and cold through the tap and check every connection point — back-nut, compression nuts, and flexible hose ends — with dry tissue paper to detect even the smallest weep. Tighten any weeping joints by a fraction of a turn. If you experience low flow after fitting, check whether the aerator is blocked with installation debris; unscrew it and rinse it clean under running water.
Frequently Asked Questions
Do I need a plumber to replace a kitchen tap?
No — replacing a like-for-like kitchen tap does not require a licensed plumber and is a straightforward DIY job for anyone comfortable using basic hand tools. However, if the job involves extending pipework, moving waste connections, or fitting a boiling water tap with an electrical element, you should involve a qualified tradesperson. For purely electrical elements, a Part P-registered electrician is required.
How do I know what size tap I need?
Most UK kitchen sinks have a 35 mm hole for a monobloc mixer tap or two 35 mm holes spaced 180 mm apart for pillar taps. Measure your existing hole before purchasing a replacement — some older sinks have non-standard hole sizes that may require an adaptor plate.
Can I replace a two-hole pillar tap with a single monobloc mixer?
Yes, but only if your sink has a single 35 mm centre hole, or you use a cover plate to bridge the two existing holes. A cover plate is typically supplied with the tap or available as an accessory. Ensure the plate material suits your sink surface — stainless, chrome, or ceramic options exist.
What should I do if water keeps dripping after fitting the new tap?
A persistent drip after fitting is almost always caused by an unseated washer or a compression joint that is one fraction of a turn too loose. Isolate the supply, disassemble the relevant joint, check the olive or fibre washer is seated correctly, and reassemble. If the tap body itself drips from the spout when closed, replacing the tap washer inside the new tap head is the next step.
Is it safe to work on my own plumbing in the UK?
Yes — tap replacement is not notifiable work under Building Regulations, so any competent homeowner can carry it out legally. Water supply work in the UK must comply with the Water Supply (Water Fittings) Regulations 1999; for guidance on what DIY plumbing is permitted, WaterSafe provides clear advice for homeowners.
Before tightening the back-nut permanently, pack a thin bead of silicone around the tap base even if a rubber gasket is supplied — on an uneven or worn sink deck, the gasket alone rarely creates a fully watertight seal and limescale-stained weeping at the base is the result. Let the silicone skin over for five minutes before final tightening so it compresses rather than squeezes out.
Sources
- WaterSafe — DIY plumbing advice for homeowners — watersafe.org.uk
- HSE — Water Supply (Water Fittings) Regulations 1999 — hse.gov.uk
- Which? — How to replace a tap — which.co.uk
Safety Notice: Electrical and plumbing work can be dangerous if done incorrectly. In the UK, certain electrical work must comply with Part P of the Building Regulations and certain plumbing work with Part G. If in doubt, consult a qualified electrician (NICEIC/NAPIT registered) or plumber (CIPHE/WaterSafe registered). This guide is for general information only — it is not a substitute for professional advice.
