A dripping tap wastes water, can stain a basin, and on a hot tap it wastes the energy you paid to heat the water. The fix is usually simple and cheap. The trick is knowing which kind of tap you have, because the inside is completely different depending on the type.
Step 1: Work out what kind of tap it is
Traditional taps with a handle that turns several times before the water stops, and tightens gradually, are compression taps. They seal with a rubber washer, and a drip almost always means the washer is worn.
Taps that go from off to fully on in a quarter or half turn, with a firm stop at each end, are ceramic disc taps. They use a cartridge instead of a washer. A drip means the cartridge or its seal has worn or has a bit of grit trapped in it.
Single-lever mixer taps, where one handle controls both flow and temperature, use a single larger cartridge. They're the fiddliest to fix because cartridges vary a lot between brands.
Step 2: Turn off the water
Look under the sink for small isolating valves on the pipes feeding the tap. Turn the slot a quarter turn with a flat screwdriver so it sits across the pipe. If there aren't any, turn the water off at the main stopcock. Open the tap to let the remaining water run out, then put the plug in so no small parts disappear down the drain.
Step 3: Take the tap apart
Prise off the decorative cap on top of the handle (a small flat screwdriver or a fingernail usually does it), undo the screw beneath, and lift the handle off. Underneath you'll find either a headgear nut (compression tap) or a cartridge body (ceramic disc or mixer).
Wrap a cloth around the nut before gripping it with an adjustable spanner, so you don't scratch the chrome, and hold the tap body steady with your other hand so you don't twist the whole tap on the basin.
Step 4: Replace the washer or cartridge
For a compression tap, the washer sits at the bottom of the headgear, held by a small nut or just pushed on. Replace it with the same size — take the old one to the shop if you're unsure. A mixed pack of washers is cheap to keep in a drawer.
For a ceramic disc tap, pull out the cartridge and check it for grit or chips. Sometimes a clean and a new rubber seal is enough. If a disc is chipped, you'll need an identical replacement cartridge, and cartridges are specific to hot or cold (they turn in opposite directions). Take the old one with you to match it.
Step 5: Reassemble and test
Put everything back in reverse order. Tighten firmly but don't force anything — overtightening can crack a cartridge or crush a new washer. Turn the water back on slowly and check for drips from the spout and leaks around the base of the handle.
When to call a plumber
Call us if the tap still drips after a new washer or cartridge, if water leaks from the base of the tap rather than the spout, if the isolating valve or stopcock won't turn, or if you can't find the right cartridge. Sometimes a tap is simply worn out and replacing it is quicker and cheaper than chasing parts.
A leaking tap in the bathroom is also worth a second look at the rest of the room. If the basin, bath taps and shower are all showing their age, it may be time to think about a new bathroom rather than fixing things one at a time. Our bathroom planner takes a minute and Adam will call you back.