How to Stop a Tap Leaking Tonight

Turn the water off before you touch the tap

Tightening a dripping tap harder does not stop it. It flattens the washer or cracks the ceramic discs, and the drip comes back worse. The first job is to take the pressure off, so the tap stops leaking while you work out what has failed.

Look under the sink or basin for the two pipes coming up to the tap. Most modern kitchens and many bathrooms have a small isolation valve on each pipe: a brass or chrome fitting with a screw slot or a little butterfly handle. Turn the slot or handle a quarter turn so it sits across the pipe, not along it. That shuts off that one tap and leaves the rest of the house working. Our guide to an isolation valve that is leaking itself covers what to do if the valve weeps when you turn it.

No isolation valves? Turn off the main stopcock, usually under the kitchen sink, in a downstairs toilet or where the water pipe enters the building. Turn it clockwise until it stops. If it is stiff, see how to turn off a stopcock before you force it.

• Kitchen cold tap, or any tap in a home with a combi boiler: the main stopcock stops it, because that water comes straight off the mains.
• Hot tap fed from a hot water cylinder with a cold tank in the loft: the stopcock will not stop the hot side. Close the valve on the cold feed pipe that runs into the bottom of the cylinder, or the gate valve on the outlet of the loft tank. Bathroom cold taps in these homes are often tank-fed too, so the stopcock may not stop them either.
• Unvented cylinder (no loft tank, a pressure gauge and relief valves on the cylinder): it runs off the mains, so the main stopcock stops both taps. The cold inlet valve on the cylinder isolates the hot side on its own.

Open a tap after isolating. If water keeps flowing strongly after half a minute, you have closed the wrong valve.

Where is the water actually coming from?

Dry the tap and the area around it with a towel, turn the water back on briefly, and watch. Where the water appears tells you which part has failed, and that decides whether this is a five-minute job or one for a plumber.

• Drips from the spout when the tap is off: the washer (older taps) or the ceramic cartridge (quarter-turn and lever taps) is no longer sealing.
• Water seeping from under the handle or round the spindle when the tap is on: an O-ring or gland packing on the spindle. See a tap leaking from the handle.
• Water pooling round the base of a swivel spout, usually on a kitchen mixer: the spout O-rings. There is a separate guide to a kitchen mixer tap leaking at the base.
• Water under the sink, in the cupboard: a flexible tap connector, the isolation valve or the waste, not the tap itself.

Which kind of tap do you have?

Turn the handle from fully off to fully on. If it takes several full turns, it is a compression tap with a rubber washer. These are common on older basins, baths and outside taps, and they are the easiest to fix. If it goes from off to full flow in a quarter or half turn, it has ceramic disc cartridges inside. If there is one lever that moves up and down for flow and side to side for temperature, it is a single-lever mixer with one larger cartridge.

Look for a brand name on the tap body or under the handle cap. A branded tap usually needs its own cartridge, and having the name makes finding the part far easier. For a mixer, our guide to whether it is the cartridge or the O-ring goes through each type in more depth.

Fixing a dripping tap that turns several times

With the water off and the tap open to drain, put the plug in so nothing falls down the waste. Prise off the decorative cap on the handle, undo the screw beneath it, and pull the handle off. On some older taps the handle is a shroud that unscrews by hand.

Underneath is the headgear, a large hexagon nut. Hold the tap body steady with one hand, or with a second spanner, and undo the headgear anticlockwise with an adjustable spanner. Holding the body matters: twisting the whole tap can crack the basin or loosen the tap from its fixings.

At the bottom of the headgear is the washer, held by a small nut or simply pushed on. Standard UK sizes are half inch for basin and sink taps and three quarter inch for bath taps. Take the old one to a hardware shop if you are not sure. Fit the new washer, refit the headgear hand tight plus a little more, and turn the water back on slowly.

If a new washer only slows the drip, the brass seat the washer presses on is probably pitted. A plumber can reface it, or you can fit a plastic seat-and-washer kit as a stopgap. More detail, including when a washer is not the answer, is in replacing tap washers.

Fixing a quarter-turn or lever tap

Ceramic taps do not have a washer to change. Two ceramic discs with holes in them slide over each other; when the holes line up, water flows. A speck of grit or limescale between the discs, or a chip on one, lets water through when the tap is off. The fix is a replacement cartridge.

Remove the handle the same way, then unscrew the cartridge with a spanner on its hexagon, holding the tap body still. Before you buy, check three things: the number of splines (teeth) on the spindle, the length of the cartridge, and whether it closes clockwise or anticlockwise. Hot and cold cartridges in a pair often turn in opposite directions. A single-lever mixer cartridge is usually 35 mm or 40 mm across the base; measure it rather than guess.

Sometimes the discs are only fouled with grit. Clean them carefully with water and a soft cloth, check the rubber seal at the base, and refit. If the drip returns within a day or two, replace the cartridge.

Do not use a pipe wrench on a chrome tap body. It marks the finish instantly. Wrap a cloth round the jaws of an adjustable spanner, or use a spanner on the hexagon only.

When a leaking tap cannot wait until morning

A dripping spout is a nuisance and a steady cost on a water meter, not an emergency. Some leaks are different. Call someone out if water is getting into the cupboard or under the floor, if a tap will not turn off at all and you cannot isolate it, if an isolation valve or the stopcock will not close, or if the tap body itself is split or has come loose from the basin. A tap that keeps running at full flow is covered in a tap that will not turn off.

As a typical market guide, a replacement washer costs pennies, a generic ceramic cartridge roughly £5 to £20, and a branded mixer cartridge anywhere from £20 to £60 or more.

Our leaking tap repair visit is a £60 call-out at any hour, day or night. The repair price is agreed with you on site before any work starts. The engineer isolates the tap, finds the failed part, fits a matched washer, cartridge or O-ring, and checks there is no drip from the spout, the handle or the connectors below.