DIY GUIDE · PLUMBING & HEATING

How to replace a kitchen mixer tap yourself
A morning. £44–£92 for a mid-range mixer, tails, valves and a basin wrench.

Same sink, same pipes, new tap. Isolate, disconnect, swap, test — and leave the pipework and the boiler alone.

DIFFICULTY
Moderate
part of the job only
TIME
Two to four hours
most of it getting the old tap off; fitting the new one is quicker
MATERIALS
£44–£92
a mid-range mixer, two isolating valves, tails if not supplied, a basin wrench
A PRO CHARGES
£60–£200
typically £100
  • Every step, start to finish
  • Checked October 2026 — sources at the end
  • Honest about when to call a pro

FIRST, THE HONEST ANSWER

Do it yourself, or get a fitter?

Do it yourself if…

  • The new tap fits the existing hole in the sink or worktop, and the hot and cold pipes already reach the cupboard
  • You can find the stopcock and it turns, or there are working isolating valves under the sink
  • You are happy working on your back in a cupboard with a torch for an hour
  • The old pipes are copper or plastic with compression or push-fit ends you can see

Get a pro if…

  • The sink is moving, the tap needs a new hole cut in stone or composite, or the pipes have to be extended or rerouted
  • The stopcock is seized, missing or leaks when you turn it
  • The hot water comes from an unvented cylinder and anything on or near it would need touching
  • The old tap's fixing nuts are corroded solid onto the tails behind the sink bowl and will not move

Safety first

  • Turn the water off and open the old tap to drain it before you undo a single nut. A tail undone under mains pressure sprays the cupboard and you.
  • Hot water comes from the cylinder or the boiler, so the hot side can scald. Turn the boiler or immersion heater off first and let the hot run cold.
  • Unplug or switch off anything electrical in the cupboard — a dishwasher, a waste disposal unit, a water softener — before water can reach it.
  • Lying in a sink cupboard with your arms above your head strains the neck and shoulders. HSE's manual handling guidance is about loads and posture; here that means a cushion under your back, short spells, and getting out to stretch.
  • Wear safety glasses when you work above your face. Grit, limescale and old water fall straight down as the nuts come loose.
  • Nothing in this job involves the gas side of the boiler. If a combi boiler feeds your hot tap, leave its case and its pipes alone.

Stop here: Stop here: new pipework, the cylinder and the boiler

A tap connected to the mains is a water fitting, and installing one must meet the water fittings rules in your nation: the Water Supply (Water Fittings) Regulations 1999 in England and Wales, the Scottish Water byelaws in Scotland, and Northern Ireland's own Water Fittings Regulations of 2009; some new installations need notice to the water supplier before work starts. A like-for-like replacement of a sink and its tap is not notifiable building work in England, but new or altered plumbing in a new bathroom is. An unvented hot water cylinder falls under requirement G3, with guidance in England's Approved Document G, and is for someone qualified in unvented systems only; Wales, Scotland and Northern Ireland have their own building regulations to the same effect. A combi boiler feeding the hot tap is gas work behind its case, restricted to Gas Safe registered engineers under the 1998 Gas Safety (Installation and Use) Regulations in Great Britain and the 2004 Regulations in Northern Ireland. How to hire a tap fitter →

MATERIALCOVERAGEFOR THIS JOB
Kitchen mixer tapPressure range in its instructions must suit your supplyOne, with the fixing kit and tails it comes with
Flexible tap tailsUsually supplied; buy separately only if too shortTwo, long enough to reach without stretching
Isolating valves15 mm compression or push-fit to match your pipeTwo, if none are fitted now
PTFE tapeOnly on a tapered male thread that has no washerA few turns; never on a compression olive

How long the tails need to be

Tail length = the distance from the underside of the tap to the end of the supply pipe, plus a gentle curve. If the pipe ends 380 mm below the tap and 100 mm to one side, a 500 mm tail reaches with a loose bend.

Never stretch a tail straight or bend it tight against itself. The tap maker's diagram shows a slight bend or a curve as right, and a kink or a twist as wrong.

Check your water pressure first

A tap has a pressure range printed in its instructions, and it matters more than the shape. One mainstream sink mixer we checked works from 1.0 to 5.0 bar and copes with mains-fed hot and cold, a combi, or an unvented system, but on a tank-fed hot supply it wants the cold tank at least 10 metres above the spout — far higher than most houses. If your hot water comes from a cylinder fed by a tank in the loft, look for a tap sold as suitable for low pressure, or the hot side will dribble.

Monobloc, bridge or two holes

Most modern kitchen mixers are monobloc: one hole, one body, two flexible tails hanging underneath. A bridge mixer has two separate bodies joined by a bar and needs two holes. Count the holes in your sink or worktop and measure their diameter before you buy. A monobloc on a two-hole sink needs a blanking plate; a two-hole tap on a one-hole sink means drilling, which this guide does not cover.

Tails, and the thread on the end of them

Flexible tails screw into the underside of the tap by hand, and their far ends are usually a 15 mm compression or a half-inch threaded nut. Check what your pipes end in. If the tails supplied are too short to reach without stretching, buy longer ones rather than adding a joint. The tap maker's own tails are the safest pairing; a tail that has been kinked, crushed or twisted is a future flood.

Isolating valves, if you have none

An isolating valve is a small inline valve on each supply under the sink, turned with a flat screwdriver. The tap maker recommends them for maintenance, and fitting a pair now means the next washer or cartridge change never needs the whole house turned off. They cost a few pounds each and go on with the same compression joint as everything else.

Spout height and reach

Measure from the sink bottom to the underside of any shelf or window sill, and from the tap hole to the centre of the bowl. A tall swan neck over a shallow sink splashes; a short spout that discharges near the back edge makes filling a pan awkward. A pull-out spray needs room under the sink for its hose and weight to move freely.

Look for the water approval

Fittings connected to the mains must meet the water fittings rules in your nation. Buy a tap whose box or listing says it meets the Water Supply (Water Fittings) Regulations or carries a recognised water approval mark. Very cheap unbranded taps often do not, and a non-compliant fitting can be required to come out.

Keep the old tap until the new one is in and dry; its fixing kit sometimes saves a trip.
Photograph the pipework under the sink before you touch it, so you know which pipe is hot.

THE PART THAT DECIDES THE FINISH

Before you start — the pipes and the space under your sink

What you find in the cupboard decides how the morning goes. Open it, take everything out, shine a torch up behind the bowl and match what you see to one of these.

Isolating valves already fitted

The easiest case. Two small valves with a screwdriver slot on each supply.

  1. Turn each slot a quarter turn so it sits across the pipe, which closes it
  2. Open the old tap on both hot and cold to prove the water has stopped
  3. Keep a bowl and a towel under the valves; the tails still hold a cupful each
  4. Check each valve body for green crust or drips; a weeping valve is worth replacing while everything is apart
Copper pipes straight to the tap, no valves

Older kitchens. The tap's own tails or long copper tails go up through the sink.

  1. Find the stopcock, usually under the sink or where the main enters the house, and turn it off clockwise
  2. Turn off the hot at the cylinder outlet valve if you have one, or drain the hot by running the hot tap until it stops
  3. Open every tap on the ground floor to drain the pipes down
  4. Plan to fit a pair of isolating valves on the pipe ends before the new tails go on
Plastic push-fit pipe

White or grey plastic pipe with push-fit elbows and valves.

  1. Isolate exactly as for copper
  2. Check each pipe end has a metal or plastic insert inside it — push-fit and compression joints on plastic pipe need one
  3. Do not use a hacksaw on plastic pipe; use a proper plastic pipe cutter for a square, clean end
  4. If you are adding a compression valve, use the insert the fitting maker specifies, pushed fully home
Old tap seized to the sink

Corroded back nuts behind the bowl that will not shift.

  1. Soak the threads with penetrating oil the night before and again in the morning
  2. Use a basin wrench, which reaches up behind the bowl where a spanner cannot
  3. If the tap is held by a threaded rod and nut, an extra-long socket on an extension bar sometimes reaches
  4. If it still will not move, cutting the old tails is an option only once the water is off and drained — and the stub ends must still be long enough to take a new fitting
A cupboard full of other things

Dishwasher valves, a waste disposal unit, a filter or a boiling water tank.

  1. Switch off and unplug any electrical item before you start
  2. Label any extra valve so it goes back to the same position
  3. Leave the appliance valves open or closed exactly as you found them unless the appliance is drained
  4. A boiling water tap with its own tank is not a like-for-like swap; leave that to the installer
Hot water from a pressurised cylinder

A tall cylinder with a cluster of valves and a small pipe to a drain, no tank in the loft.

  1. Changing the tap is still yours; anything on the cylinder is not
  2. Turn the hot off at the tap's isolating valve, not at the cylinder
  3. Do not drain, adjust or touch the valves on the cylinder itself
  4. Check the new tap's instructions say it is suitable for unvented systems

THE JOB

How to replace the tap

  1. Set up: clear the cupboard and isolate the water

    30 min

    Empty the cupboard and lay towels on its floor. Find your case in the cards above and follow it: close the isolating valves, or turn off the stopcock and drain the pipes. Turn off the boiler or immersion heater so the hot side cools. Open the old tap on hot and cold and leave it open; if water keeps coming after a minute, something is still on.

    • Photograph the pipes and valves before you touch anything
    • Put a plug in the sink so a dropped washer or nut does not go down the waste
    • Tell everyone in the house not to turn the water back on

    Mistake to avoid: Trusting a stopcock you have not tested. Turn it, open the tap, and watch for a full minute. An old stopcock that only half closes lets mains water spray out the moment you undo a tail.

  2. Prepare the space and check the pipe ends

    20 min

    This is the prep from the cards above, done with the water off. Put a bowl under each valve. Look at where each pipe ends: a compression nut, a push-fit collar or a threaded valve outlet. Check the stub of pipe below any valve is straight, round and long enough to take a new fitting. Lay your tools on a towel where you can reach them without sitting up.

    • A cushion or folded towel under the cupboard edge saves your back
    • If the sink waste is in the way, undo the trap now and put it in a bucket
    • Check which pipe is hot by feel or the photograph, and mark it with tape

    Mistake to avoid: Discovering the pipe end is too short or crushed after the old tap is off. Check first; if the pipe needs cutting back or extending, the job has changed.

  3. Disconnect the old tails

    15 min

    Hold the isolating valve or the pipe fitting still with one spanner and undo the tail's nut with the other, turning anticlockwise as you look at the nut. Keep the bowl underneath. Undo hot and cold, then let the tails hang. If the old tap has copper tails soldered or compressed straight onto the pipe, undo the compression nut on the pipe below.

    • Always use two spanners; one on its own twists the pipe and cracks the joint above
    • Let each tail drain into the bowl before you move it
    • Keep the old nuts and olives in a labelled bag until the job is done

    Mistake to avoid: Turning the nut with a single spanner. The torque goes into the pipe instead, and a joint you had no plan to touch starts leaking.

  4. Remove the old tap

    45 min

    Reach up behind the bowl with the basin wrench and undo the back nut or the fixing nut on the threaded rod, again anticlockwise from below. Older taps have one large nut on each tail; most modern monoblocs have a single rod with a nut and a horseshoe-shaped washer. Once the nut is off, lift the tap and its tails up and out through the hole from above.

    • Give stubborn nuts several short pulls rather than one big heave
    • Have someone hold the tap from above so it does not spin while you turn the nut
    • Scrape the old seal ring and any limescale off the sink top around the hole

    Mistake to avoid: Forcing the tap round from above to free a stuck nut. A stainless sink flexes and a composite one can crack round the hole. Turn the nut, not the tap.

  5. Fit the tails into the new tap

    10 min

    On the bench, screw the two flexible tails into the underside of the new tap by hand only. The tap maker is explicit that they must not be over-tightened: the threads are fine and the seal is an O-ring, not the thread. Screw in the fixing rod too, if your tap has one, and slide the base gasket or plinth onto the bottom of the tap body.

    • Hand tight means firm with your fingers; no spanner at all on the tap end
    • Check the O-rings on the tail ends are seated and not nicked
    • Note which tail is hot; most taps put hot on the left as you face the sink

    Mistake to avoid: Using a spanner on the tap end of the tails. The small brass thread in the tap body strips, and the tap is scrap.

  6. Fix the tap to the sink

    20 min

    Feed the tails down through the hole and stand the tap in place with its gasket or plinth under it. From below, slide the rubber washer and then the metal horseshoe washer onto the fixing rod, up against the underside of the sink, and run the nut up the rod. Have someone hold the spout straight from above while you tighten the nut fully with a spanner or the basin wrench.

    • Line the spout up with the centre of the bowl before the nut is tight
    • Tighten until the tap cannot be twisted by hand, and no further on a thin stainless sink
    • Swing the spout through its arc to check it clears the window sill and any shelf

    Mistake to avoid: Tightening the fixing nut with the tap crooked. Once tight, it will not turn back without loosening everything again, and a squint tap is all anyone sees.

  7. Connect the tails to the supplies

    20 min

    Bring each tail down to its valve in a gentle curve, with no kink and no twist. Connect hot to hot and cold to cold. On a compression valve, slide the nut and a new olive onto the pipe if you are refitting, push the pipe fully home to its stop, run the nut up by hand, then tighten with two spanners. The fitting maker we checked gives about a turn and a quarter past hand tight for small sizes; snug, not crushing. Threaded tail ends with a fibre or rubber washer need only firm hand tightness plus a little.

    • Use a new olive on any compression joint you have opened; old ones rarely reseal
    • Never put PTFE tape on an olive or a compression thread
    • If a tail is too long, loop it gently rather than kinking it

    Mistake to avoid: Crossing hot and cold. The lever then works backwards, which is merely annoying, unless the tap has a check valve that now sits the wrong way.

  8. Flush and test

    20 min

    Close the old tap's handle position on the new tap. Open the isolating valves or the stopcock slowly, a little at a time, and watch every joint with the torch and a dry piece of kitchen roll. If all is dry, open the new tap fully and run both hot and cold for a few minutes. The maker asks for this flush because grit and swarf in the pipes damage the cartridge. Then turn the boiler back on.

    • Wipe each joint dry and hold a tissue under it; a tissue shows a weep long before you see a drip
    • A joint that weeps usually needs a quarter turn more, not a full turn
    • Fit the aerator back on the spout only after the flush

    Mistake to avoid: Turning the water back on full and walking away. A small weep under a sink can run for weeks unnoticed and rot the cupboard base.

  9. Check again the next day

    10 min

    Look under the sink the next morning with a torch and a dry tissue on each joint. Joints settle in the first day. Check the tap body is still tight on the sink and the lever moves smoothly through hot and cold. Put the cupboard contents back only once everything has stayed dry overnight.

    • Leave a sheet of kitchen roll on the cupboard floor for a week; any mark shows a drip
    • If the flow is weak on one side, check that isolating valve is fully open
    • Keep the tap's instructions and spare parts in a bag taped inside the cupboard

    Mistake to avoid: Restocking the cupboard straight away. Bleach and bin bags hide a drip until the board under them has swollen.

The mistakes that show

  • Using a spanner on the tails where they screw into the tap body
  • Undoing joints with one spanner and twisting the pipe behind
  • Reusing old olives on compression joints, which then weep
  • Buying a tap whose minimum pressure your hot supply cannot reach
  • Stretching or kinking the flexible tails to make them reach

Stop here and get a plumber

  • The pipework has to be moved, extended or teed into to reach the new tap
  • The stopcock will not turn off fully, or it leaks when you try
  • The hot supply is from an unvented cylinder and anything on the cylinder would need touching
  • A new hole has to be cut in a stone, composite or ceramic worktop or sink
How to hire a tap fitter →

New tap dripping from the spoutGrit from the pipes has lodged in the cartridge. Isolate, take the handle off as the tap's maintenance page shows, lift the cartridge, rinse it under cold water and refit. Flushing before fitting prevents it.
Water leaking where the tail joins the valveThe nut needs a quarter turn more with two spanners, or the olive was reused or is not square. Isolate, undo, fit a new olive, and remake it.
Leak from the base of the tap on the worktopThe base gasket is not seated, or the fixing nut is loose. Tighten the nut from below with the spout held straight; if water still gets under, the gasket is folded.
Weak flow on the hot sideThe hot supply pressure is below the tap's minimum, or an isolating valve is only part open. Open the valve fully; if it is a tank-fed supply, the tap may need changing for a low-pressure model.
Lever works backwards — hot on the rightThe tails are connected to the wrong supplies. Isolate and swap them over at the valves.
Tap loose and spins on the sinkThe fixing nut is not tight against the horseshoe washer, or the washer is missing. Tighten from below, holding the tap straight.
Banging or shuddering when the tap shutsWater hammer, usually from a loose pipe or a fast-closing lever on high pressure. Clip loose pipes under the sink; if it persists, a plumber can fit an arrestor.
Spray or pull-out head drips at the hoseThe hose connection inside the body is not fully pushed or screwed home. Isolate and reseat it as the instructions show.

WHAT YOU SAVE

What it costs to do it yourself

Mid-range kitchen mixer tap£25–£60
Pair of isolating valves£5–£12
Flexible tails, if not supplied£7–£10
Basin wrench£7–£10
Total£44–£92
DIY total£44–£92
A tap fitter charges per tap
LOW
£60
TYPICAL
£100
HIGH
£200
Tap & Mixer Installation price guide →

Guide prices compiled by the Locufy team from published Irish and UK provider price lists and 2026/27 cost guides. Updated 2026.

Against a plumber's guide price for fitting a tap, the saving is real but modest; the tap itself is the biggest cost either way, and the basin wrench is a tool you keep.

RATHER NOT?

Tap fitters near you, with prices shown

The ones who cover your area, nearest first, with one score from every review. No account needed to look.

Or post the job free and let them come to you.

Keep the instructions and spares

Tape the tap's leaflet and any spare O-rings in a bag inside the cupboard door. The cartridge maintenance page is the one you will need in two years.

Descale the aerator

In a hard-water area, unscrew the aerator on the spout every few months and soak it in vinegar or descaler; a sputtering spout is usually a blocked aerator.

Dispose of the old tap

The old tap is mostly brass and chrome-plated metal. Take it to the metals container at your council's household waste recycling centre, along with old valves and tails; find your nearest through the council website or the recycling pages for your nation.

Exercise the isolating valves

Turn each one off and on again twice a year. A valve left untouched for years seizes, and then it is no use in the one moment you need it.

Replacing a kitchen mixer tap like for like: questions people ask

Yes, if the new tap goes into the same hole on the same sink and connects to the existing hot and cold pipes. Moving pipes, adding supplies or touching an unvented cylinder or the boiler is a plumber's job.

Only if there are no isolating valves under the sink. With valves, close them with a flat screwdriver. Without them, turn off the stopcock and drain the pipes — and consider fitting valves while it is all apart.

Most likely the hot supply is tank-fed at low pressure and the tap needs more. Taps list a minimum pressure in their instructions; one we checked needs 1.0 bar, or a tank 10 metres above the spout on gravity hot water. Choose a low-pressure tap for that kind of system.

No. Tap tails seal on an O-ring at the tap end and on a washer or olive at the valve end. Tape on a compression olive stops it seating; use it only on a tapered thread with no washer.

Into the tap body, hand tight only — the maker says so in capitals. At the valve, compression nuts go a little past hand tight with two spanners, and washer-type nuts need firm hand pressure and a small extra turn.

Locufy's UK price guide puts tap and mixer installation at £60–£200 per tap, typically £100 — the same three figures as the strip at the top of this page. The tap itself is extra either way.

MORE GUIDES

More DIY guides

Replacing a basin waste and bottle trapPlumbing in a washing machine or dishwasherFixing a dripping tap or a weeping jointDoing the small plumbing jobsResealing a bath, shower or sinkHandling a plumbing emergency until help arrivesBleeding radiators and re-pressurisingUnblocking a sink, bath, toilet or outside drain
All 90 DIY guides →How to hire a tap fitter →Tap & Mixer Installation price guide →Tap fitters on Locufy →

Sources — checked October 2026

  1. Bristan — Melba sink mixer installation instructions: pressure range, hand-tight tails, flushing
  2. Flowflex — compression fittings technical data and installation instructions
  3. HSE — manual handling at work
  4. Water Supply (Water Fittings) Regulations 1999, regulation 5
  5. Water Supply (Water Fittings) (Scotland) Byelaws Extension Order 2024
  6. Water Supply (Water Fittings) Regulations (Northern Ireland) 2009
  7. gov.uk — Approved Document G: sanitation, hot water safety and water efficiency (England)
  8. gov.uk — building work, replacements and repairs to your home (England)
  9. Gas Safety (Installation and Use) Regulations 1998, regulation 3
  10. Gas Safety (Installation and Use) Regulations (Northern Ireland) 2004, regulation 3
  11. gov.uk — recycling collections: find your council (England and Wales)
  12. mygov.scot — find your council's recycling centre (Scotland)
  13. nidirect — recycling and reusing (Northern Ireland)
  14. B&Q — price check: kitchen mixer taps
  15. B&Q — price check: flexible tap connectors
  16. B&Q — price check: isolating valves
  17. B&Q — price check: basin wrenches