How to Replace a Kitchen Tap: Step-by-Step Guide

How to change a kitchen mixer tap yourself: choosing a tap that suits your water pressure, isolating the water, removing the old tap, fitting the new one and fixing the leaks that often follow.

To replace a kitchen tap, turn off the hot and cold isolation valves under the sink, open the tap to drain it, disconnect the flexible hoses and undo the fixing nut under the worktop. Lift the old tap out, clean the hole, screw the new tap's hoses into its base, feed it through with its seal and fix it from below. Then connect the hoses, turn the water back on slowly and check every joint for drips. It's one of the more manageable plumbing jobs to do yourself. What catches people out is buying a tap that doesn't suit their water pressure, having no way to turn the water off under the sink, and a fixing nut that's rusted solid. This guide covers each step and those problems.

Before you buy

Check your water pressure. This is the most common reason a new tap disappoints. Many modern mixer taps, especially tall spouts and pull-out sprays, are designed for mains pressure on both hot and cold. If your hot water comes from a cylinder in an airing cupboard fed by a tank in the loft, the hot side is low pressure and some taps will barely run. Look for a tap rated for low pressure, or check the minimum pressure in its specifications, often given in bar. A combi boiler or unvented cylinder usually gives mains pressure to both sides. If your cold water is weak too, our guide to low water pressure helps you work out why.

Measure the hole. Most monobloc mixers need a single hole of about 35mm. Older sinks often have two holes for separate hot and cold pillar taps. You can fit a two-hole mixer, or a single mixer with a blanking cap over the spare hole.

Check the connections. Most mixers come with flexible hoses that screw into the tap base and end in a fitting for standard 15mm pipe or a 1/2 inch valve. Check the hoses are long enough to reach your valves without stretching.

Specialist taps. Boiling water taps, filter taps and some pull-out sprays have extra parts, such as a tank or filter under the sink, an electrical supply, or a check valve. The Water Supply (Water Fittings) Regulations require protection against backflow wherever a hose could sit in dirty water in the sink, so fit any check valves the maker supplies. These taps are usually better fitted by a plumber.

Tools and parts

Two adjustable spanners
A basin wrench or long-reach tap spanner for the fixing nut
A flat screwdriver for the isolation valves
A torch, a bowl and old towels
Spare fibre washers, and possibly new isolation valves if the old ones are stiff
Something soft to kneel on, as you'll be inside the sink cupboard for a while

Turn off and drain

Empty the cupboard

Clear everything out from under the sink and put a towel down. Take a photo of the pipes so you can remember how they went.

Close the isolation valves

Find the small valves on the hot and cold pipes. Turn each slot a quarter turn so it sits across the pipe. If there are no valves, or they won't turn, turn the water off at the stopcock. If the stopcock is stiff, see stopcock won't turn.

Drain the tap

Open the tap fully on hot and cold. It should run for a few seconds and stop. If it keeps running, the valves aren't sealing, so use the stopcock instead.

Remove the old tap

With the bowl underneath, undo the nuts where the tap's hoses meet the isolation valves. Hold the valve still with one spanner while you turn the nut with the other, so you don't twist the pipe. A little water will come out.
Under the worktop, find how the tap is held. Most mixers use a threaded stud with a horseshoe-shaped plate and a nut. Older taps have a large back nut on each tail.
Undo the fixing with a basin wrench. If it's rusted, soak it with penetrating oil and give it time before trying again.
Lift the old tap out from above and clean off old sealant, limescale and grime around the hole so the new seal sits flat.

If the fixing won't shift, or the sink is so rusted that you're worried about damaging it, stop there. A plumber can cut off a seized fixing without damaging the sink.

Fit the new tap

Screw in the hoses first

Screw the flexible hoses into the base of the new tap by hand, then nip them up gently, as the instructions say. Don't overtighten. The thread is often brass and the O-ring seals it, not force. Hot is usually on the left as you face the tap.

Fit the seal and feed it through

Put the rubber gasket or O-ring on the base of the tap, then feed the hoses and stud down through the hole.

Fix it from below

Slide the backing plate and horseshoe washer onto the stud and tighten the nut while someone holds the spout straight from above. It should be firm enough not to twist when you use the lever.

Connect to the valves

Connect each hose to the right valve, using the washers supplied. Keep the hoses in gentle curves with no kinks or sharp bends.

If the new hoses don't reach, or the old pipes finish at a different height, you may need a short extension or new valves. Don't stretch a hose to make it fit, as a strained braided hose is a common cause of a burst under the sink. If you already have water in the cupboard, our guide to a leak under the kitchen sink helps you find where it's coming from.

Turn on and test

Unscrew the aerator from the end of the spout if you can. It catches debris that comes loose when the water goes back on.
Open the isolation valves slowly and check each joint with a dry tissue. It shows drips far better than your fingers.
Run the tap on hot and cold for a minute, then refit the aerator.
Check the joints again after an hour and the next morning. Slow weeps often show up later.

Problems after fitting

Problem	Likely cause	Fix
Drip where the hose meets the valve	Missing washer or nut not quite tight	Check the washer, then a small extra turn
Drip where the hose enters the tap	Hose not screwed fully home	Turn the water off, unscrew and refit
Weak flow on one side	Valve part-closed, debris, or low-pressure supply	Open the valve fully, rinse the aerator
Tap wobbles	Fixing nut loose	Tighten from below while holding the spout
Hot and cold reversed	Hoses swapped	Swap them at the valves
Water under the sink but joints dry	Waste or trap leaking	Check the waste joints, not the tap

If an old valve starts dripping once it's been turned, it's worn and should be replaced. Our guide to a tap that won't turn off covers what to do if the new tap won't close properly, and how to fix a dripping tap covers repairs if you'd rather keep the tap you have. If the sink drains slowly once the tap is in, see kitchen sink blocked.

When to call a plumber

Get a plumber in if the old tap is seized in place, there are no isolation valves and the stopcock won't shut off fully, the pipes need moving or extending, you're fitting a boiling water or filter tap, or you have a leak you can't stop. We fit and repair kitchen taps across London and can fit isolation valves at the same visit. Our labour is £95 an hour, the £60 call-out is waived when the job runs over 2 hours, and we confirm the price before any work starts.

Rather have it fitted for you?

Tell us which tap you've bought and what's under your sink. We'll confirm the price before starting.

📞 Call 020 7870 3200

Or see our tap repairs and pricing.

Frequently Asked Questions

Can I replace a kitchen tap myself?

Yes, if you can turn the water off reliably and work in the cupboard under the sink. A like-for-like mixer tap with flexible hoses is a manageable DIY job. It gets harder if the old tap is corroded in place, there are no isolation valves, the pipes need altering, or the new tap is a boiling water or filter tap with extra connections.

How long does it take to change a kitchen tap?

With isolation valves and a tap that comes off easily, an experienced person can do it in under an hour. For a first attempt, allow two to three hours, including time to deal with a stubborn fixing nut and to check for leaks afterwards.

What tools do I need to replace a kitchen tap?

Usually two adjustable spanners, a flat screwdriver for the isolation valves, a torch, a bowl and towels. A basin wrench or long-reach tap spanner makes the fixing nut under the sink much easier to reach. You may also need new isolation valves or fibre washers.

Why is my new kitchen tap low pressure?

The usual reasons are a tap designed for high pressure fitted to a low-pressure hot supply, an isolation valve not fully open, or debris caught in the tap's aerator or flow restrictor. Unscrew and rinse the aerator, open the valves fully, and check the tap's minimum pressure rating against your system.

Do I need to turn the water off at the stopcock to change a tap?

Not if there are working isolation valves on the hot and cold pipes under the sink. Turn the slot across the pipe and open the tap to check nothing comes out. If there are no valves, or water still trickles through, turn the water off at the stopcock, and turn off a gravity-fed hot supply at the cylinder if you have one.