Stop a whistling or banging tap by isolating the water, replacing the worn washer or cartridge, and checking loose pipes.
TP-01Work out what's causing the noiseA whistle usually means a worn washer or a worn valve seat letting water squeeze through a narrow gap. A bang (water hammer) is often a loose pipe clip, or a worn washer vibrating as the tap closes. Check whether you have a traditional tap with a rounded or cross-top head, or a modern lever tap that turns a quarter turn — this decides which parts you need.
TP-02Gather tools and the right partsBuy a washer that matches your tap size, or a like-for-like cartridge if you have a lever tap — take the old part to the shop or check the tap's brand and model first. Get an adjustable spanner, a flat screwdriver, PTFE tape and a clean cloth.
TP-03Turn off the water and drain the tapShut the isolation valve under the sink, or the stopcock if there isn't one, and turn the tap on fully to drain any water left in the pipe. Plug the sink or place a cloth over the plughole so small screws and washers can't fall down it.
TP-04Remove the tap handleLay a cloth in the basin to catch any dropped parts. Prise off the small decorative cap on top of the handle with the screwdriver, then undo the screw underneath and lift the handle straight off.
TP-05Remove the headgear or cartridgeUse the adjustable spanner to unscrew the large nut (headgear on a traditional tap, or the cartridge retaining nut on a lever tap). Lift the old part straight out and note which way round it sits, so the new one goes in the same way.
TP-06Fit the new washer or cartridgeOn a traditional tap, undo the small nut holding the washer to the jumper and swap the washer for an exact match. On a lever tap, drop in the new cartridge the same way round as the old one. Smear a thin layer of plumber's silicone grease on any rubber O-rings so the tap turns smoothly.
TP-07Check the valve seatRun a fingertip over the metal seat inside the tap body. If it feels smooth, carry on. If it's pitted or rough, that's often what's causing a whistle even with a new washer fitted. A seat can sometimes be smoothed with a reseating tool, but if it's badly worn it's simpler and safer to call a plumber or fit a new tap.
TP-08Put the tap back togetherWind the headgear or cartridge back in by hand, then nip it up gently with the spanner — don't overtighten, as this can crack the seat or cartridge. Refit the handle, tighten the retaining screw, and click the decorative cap back on.
TP-09Check pipe clips while you have accessBanging often comes from a loose pipe knocking against a cupboard wall or joist as the tap turns on and off, not from the tap itself. While you're under the sink, check the clips holding the supply pipe are tight, and add a new clip if the pipe can move freely.
TP-10Turn the water back on and testOpen the isolation valve or stopcock slowly. Turn the tap fully on, then fully off, and listen for whistling or banging. Check around the handle and base of the spout for drips, and nip up the headgear a touch more if you see any.
TP-11Tidy upWipe down the sink and worktop, and bin the old washer or cartridge. Run a couple of taps around the house briefly afterwards — this clears any trapped air in the pipes, which can cause its own banging noise for a few minutes after you've been working on the system.
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