Tap Won't Turn Off: How to Stop It Running Right Now

Stop the water first

Put the plug in or a bowl under the tap if the sink might overflow. Then work back along the pipe from the tap. If you have never had to find it, our where is my stopcock guide shows the usual places, and our guide on how to turn off hot water supply from a cylinder covers the hot side.

• An isolating valve on the pipe under the sink or basin: quarter turn with a flat screwdriver, slot across the pipe.
• The main stopcock, most often under the kitchen sink: turn clockwise until it stops. This stops every cold tap and, on a mains fed system, the hot as well.
• For a hot tap on a tank fed cylinder: close the valve on the cold feed pipe running from the loft tank into the cylinder, or the valve on the tank outlet. Hot water will stop once the pressure drops.
• For a hot tap on an unvented cylinder or combi boiler: the main stopcock stops it, because both run off the mains.

If you cannot find or turn any of these and the sink is filling faster than it drains, leave the plug out, keep the drain clear and call us on 020 4652 5111.

Old style taps: a worn washer

If your tap needs several full turns to go from off to fully on, and it gets harder and harder to turn off before finally dribbling on regardless, it is a traditional compression tap. Inside is a rubber washer on a jumper that presses down onto a seat. As the washer wears, you have to turn harder to seal it. Eventually no amount of turning stops the flow, and people often strip the thread by trying.

The fix is a new washer, and sometimes a reground or replaced seat if the brass underneath has been cut by years of water. With the water off, the head of the tap is unscrewed, the old washer swapped, and it goes back together. On a tap that has been over-tightened for months, the spindle thread may be worn as well, in which case a new tap head or a new tap is the better repair.

Quarter turn and lever taps: a failed cartridge

If your tap goes from off to full on in a quarter or half turn, or it is a single lever mixer, it has a ceramic cartridge inside. Two ceramic discs slide over each other to open and close the waterway. They do not wear the way a washer does, but they fail in other ways: scale jams them part open, grit from the mains gets between the discs and chips them, or the small rubber seals on the cartridge perish.

The symptom is either a tap that will not close fully, a handle that spins without doing anything, or a lever that feels gritty and stiff. London hard water is hard on these cartridges, particularly on the hot side, and our guide to hard water and hot water cylinders in London covers what the same scale does elsewhere. A replacement cartridge has to match the tap exactly, so it helps to know the make of the tap. If the make is unknown, the old cartridge is taken out and matched.

The handle turns but nothing happens

If the handle spins freely and the tap keeps running, either the handle has come away from the spindle, or the spindle itself has stripped or snapped. Pop the cover off the top of the handle and check the retaining screw. If it is tight and still spinning, the splines on the spindle have worn and the cartridge or tap head needs replacing. Do not try to grip the spindle with pliers with the water on, because if it snaps completely you lose any control you had.

A stiff tap that is getting hard to turn

A tap that is stiff but still closes is giving you warning. On a washer tap, the washer is hardening and you are compensating by turning harder. On a cartridge tap, scale is building up around the discs. Deal with it before it jams open, which is always at the worst moment. The repair is the same as for a tap that will not turn off, but it is simpler when the water is not running.

Is it the tap or the toilet?

If you can hear water running but no tap is open, it is usually a toilet cistern refilling constantly, or the float valve in a loft tank letting by. Lift the lid off each cistern and look for water trickling into the pan, or an overflow pipe dripping outside. On a tank fed system, a tank that never stops filling points to the float valve in the cold water tank in the loft or the small header tank next to it. Our guide to a header tank overflowing covers that one.

Repair or replace the tap?

A new washer or cartridge is usually the sensible first repair. It is worth replacing the tap instead if the body is corroded or leaking from the base, the spindle thread is stripped, parts for that tap are no longer made, or the tap is old enough that other parts are close behind. If the tap is a mixer, the other side will often go soon after, so we normally suggest doing both cartridges at the same visit.

While we are there, we check the isolating valves under the tap. Most homes do not have them on every outlet, and a tap that will not turn off is exactly when you find out. Fitting them makes the next repair much simpler. If the drip is from the pipes below the tap rather than the spout, our guide to a leaking pipe under the sink covers those. Our guide to an isolation valve leaking explains what they are.

Getting it fixed

Call us on 020 4652 5111 or send an enquiry with a photo of the tap and, if you can, a photo underneath. Most taps that will not turn off are fixed in one visit with a new washer, cartridge or tap. If the water is off and nothing is leaking, it can wait for a convenient slot. If you cannot turn it off at all, tell us, and we will prioritise it. We have 20 engineers across London, and our rate is on the pricing page and agreed before anyone attends.