How to Stop a Leaky Tap in Minutes

A dripping tap is the smallest plumbing fault in the house and one of the most expensive to ignore. It wastes water every hour of every day, it stains the basin it drips into, and it slowly wears the very part that is failing, so a repair that starts as a five-minute job can end as a replacement tap. The fix itself is within reach of most households, provided the diagnosis is right and the reassembly is careful.

Why a drip gets worse

The drip is a symptom, and the part causing it is worn or scaled. Water passes the worn part continuously, and that flow does two things: it erodes the surface the part seats against, and it leaves mineral deposits behind. A tap left dripping for months tends to need more than the washer that started the problem, because the seat it presses against has been cut into by the constant flow. Fixing the drip early keeps the repair small.

There is a second reason not to wait. A drip at the spout is visible, but the same wear at a tap base or under a sink shows up as damp, and damp inside a cabinet or a wall is a much larger job than a washer. The rule of thumb is that the tap should be repaired when it starts to drip, not when it starts to matter. On a hot water line there is a further cost, because every drip draws the water heater into service to replace the hot water lost, so the waste runs to the energy bill as well as the water bill.

Before you start

Three preparations make the job shorter.

Shut off the water. Most taps have an isolator valve under the sink or beside the toilet; where there is none, use the main valve. Open the tap you are about to work on afterwards, so any water left in the pipe runs out and you can confirm the supply is truly off.

Plug the drain. Small parts fall, and a washer that drops into an open waste is an hour lost. A plug, or a cloth pushed loosely into the basin, prevents a lost part and a wasted trip.

Gather the parts and tools. A spanner, a screwdriver, a cloth, and the replacement washer or cartridge. Take the old part to the shop with you where possible, because tap parts are not standard across brands and a guess at the size rarely fits.

The five-step fix

Step 1: Isolate and drain the tap

Shut off the supply at the isolator or the main, then open the tap fully to release the pressure and drain the body. If the tap is a mixer, open both sides. If water continues to run with the tap open, the isolator is not holding and the main needs to be used instead.

Step 2: Identify the tap type

The tap in front of you is one of a few common designs, and the part to replace depends on which.

A traditional washer tap turns through a full arc, often a turn or more, and its mechanism is a spindle that presses a rubber washer down onto a seat. A ceramic cartridge tap, usually a quarter-turn lever, has no rubber washer to replace; inside is a cartridge with two ceramic discs that rotate across each other, and the whole cartridge is the part that wears. A mixer combines hot and cold through one body and most often uses cartridges as well.

The difference matters at the counter. A washer costs little and a cartridge costs more, and buying the wrong one wastes the trip. Where the tap is a mixer, the hot and cold sides usually carry one cartridge each, and only the side that drips is replaced. Cartridges are not interchangeable between brands, so it is worth noting the model number, which is often under the handle or on the underside of the spout, before going to the shop.

Step 3: Dismantle the tap in order

Remove the handle, then the head or shroud, then the spindle or cartridge. The useful habit is to lay the parts out in the order they came off, because reassembly in reverse order is what makes the job quick. Note where each O-ring sits as you go. If the spindle or cartridge resists, do not force it; corrosion around the threads is a sign the tap may need more than a part.

Step 4: Replace the worn part, and read the seat

With the tap apart, the diagnosis becomes visible.

A rubber washer that is flat, ridged or crumbling is the cause where the tap is a washer type. Replace it, and check the jumper or spindle that carries it. For a ceramic cartridge, the cartridge itself is replaced; there is nothing to service inside it.

The seat is the surface the washer presses down onto, and it is where the second diagnosis matters. A worn washer leaves a washer that looks tired. A worn seat leaves a washer that looks fine, or a new washer that begins dripping again within days, because the surface it seals against is pitted or grooved. Where the damage is light, a plumber can resurface the seat with a reseating tool. Where the seat is deeply cut or the tap body is corroded or cracked, the sensible repair is a replacement tap rather than a third attempt with washers.

Step 5: Reassemble without cross-threading

Threads are soft metal and easy to damage, and a cross-threaded tap leaks from the join no matter how good the washer is. The technique is to turn the fitting backwards first, gently, until the thread drops into its start position, then turn it forwards by hand before any spanner comes out. Tighten firm, not brutal: over-tightening crushes washers, distorts cartridges and cracks tap bodies, and none of that shows until the water is back on.

Test it properly

Turn the supply on slowly rather than all at once, and let the tap run while you watch three places: the spout, where the drip was; the base of the tap, where a body seal would show; and the connections underneath, where a supply line might have been disturbed. Dry everything first, so a new leak is visible rather than masked by the water from testing.

If the drip is gone, close the tap and check the same three spots once more after a few minutes. If it persists, the diagnosis needs revisiting: a drip that continues after a new washer points to the seat, and a drip from a cartridge tap that persists after a new cartridge points to a damaged body or a seat behind the cartridge. A drip that appears only when the tap is half open, and stops when it is closed fully or opened fully, is a washer or seat symptom rather than a body fault, and it is usually the easier of the two to repair.

When it is no longer a DIY repair

Some taps refuse the treatment above, and the honest list of exceptions is short. A tap body corroded into the wall, a seized isolator, water appearing under the floor rather than at the spout, or a tap that cannot be shut off at all are jobs for a plumber. So is any bath or shower tap with concealed pipework, where undoing the wrong fitting turns a drip into a leak inside the wall.

It is worth having a local emergency plumber who covers your area saved in advance, so the decision to call one is a phone call rather than a search at the moment a drip becomes a stream. Winter brings its own plumbing emergencies too, and they call for a different response; what to do when pipes freeze overnight is worth reading before the first cold snap rather than during one.

When the whole tap is the better repair

Replacing a tap instead of repairing it is the right call more often than people expect. A tap that has dripped for a long time, a body that is corroded or cracked, a seat cut too deeply to resurface, or a set of parts that no longer matches anything available all point the same way, and the new tap also resets the clock on the parts that have not yet failed. Where the house has two taps of the same age, expect the second one to follow the first, and buy the parts for both in one trip.