A Dripping Tap Is Usually a Washer or a Cartridge

Everything here earned its place by changing an outcome. Nothing about fixing a dripping tap is included to round the number up.

Two designs, two faults

A traditional tap turns through several rotations and seals by pressing a rubber washer down onto a seat inside the body. A quarter-turn tap uses two ceramic discs that rotate against each other, and it seals when the holes in them no longer align.

A dripping traditional tap almost always means a perished washer or a damaged seat, both of which are cheap parts. A dripping quarter-turn tap means a worn cartridge, which is replaced as a complete unit rather than repaired. You can tell them apart in two seconds by how far the handle turns, which determines everything that follows.

Before you touch anything

Close the isolation valve on the supply pipe to that tap, or the main stopcock if there is no local valve. Open the tap afterwards to release pressure and confirm the water is genuinely off rather than merely slowed. Put the plug in or cover the drain with a cloth, because the small screw you drop will otherwise be gone permanently.

On a Sunday evening, lay a towel in the basin to protect the surface and to give you somewhere to put parts in the order they came off. Photograph each stage as you dismantle, since reassembly is where most first attempts go wrong.

Replacing a washer

The handle usually lifts off after removing a small cover and screw, revealing the valve body which unscrews with a spanner. The washer sits at the bottom of that assembly, held by a small nut or pushed onto a spigot, and it will look flattened or split. Take the old washer with you to buy the replacement, because sizes vary and a near fit will leak again within weeks.

Check the seat inside the tap body while it is open, since a pitted seat will destroy a new washer quickly. Reassemble in the reverse order, hand tighten and then a small amount more, because overtightening damages the parts you just fitted.

Replacing a cartridge

Ceramic cartridges are removed as a complete unit once the handle and any retaining nut are off. They are not universal, so take the old one to the merchant or match the manufacturer and model rather than guessing. Note the orientation before removing it, since fitting a cartridge the wrong way round reverses hot and cold.

Clean any debris from the seat before fitting the new one, as grit is a common reason a new cartridge weeps immediately. If the cartridge is unavailable or the tap is a sealed design, replacing the tap is usually the cheaper route.

When it is not the washer

Water appearing at the base of the spout or around the body indicates a failed body seal rather than a valve washer. Water under the sink or at the pipe connections is a joint or a supply pipe problem, which is a different repair entirely. A tap that drips only when another is running, or that hammers when closed, points to a pressure or system issue.

If the isolation valve or stopcock will not close, stop and call a plumber rather than forcing a seized valve. In a rented flat, all of this is normally the landlord's responsibility, and reporting it costs you nothing.

Buy the cheap version first; a month of use tells you whether it deserved better.

Whether it is worth the effort

A continuously dripping tap wastes a measurable volume of water, which matters financially on a metered supply and environmentally on any supply. A hot tap dripping wastes heated water, which is the more expensive of the two.

By the second month, the repair parts cost very little, and the same fault will recur on other taps in the flat, so the knowledge is reusable. The time cost is genuinely small once you have done it once, and the first attempt is the slow one. Where the tap itself is old, corroded or a sealed cartridge design with no parts available, replacement is the honest answer.

Everything above, in order of what to do first

1. Two designs, two faults. A traditional tap turns through several rotations and seals by pressing a rubber washer down onto a seat inside the body.
2. Before you touch anything. Close the isolation valve on the supply pipe to that tap, or the main stopcock if there is no local valve.
3. Replacing a washer. The handle usually lifts off after removing a small cover and screw, revealing the valve body which unscrews with a spanner.
4. Replacing a cartridge. Ceramic cartridges are removed as a complete unit once the handle and any retaining nut are off.
5. When it is not the washer. Water appearing at the base of the spout or around the body indicates a failed body seal rather than a valve washer.
6. Whether it is worth the effort. A continuously dripping tap wastes a measurable volume of water, which matters financially on a metered supply and environmentally on any supply.

The takeaway

Count the turns of the handle, isolate the water, plug the drain, and take the old part to the shop.

A home that works is a set of small systems, not one big clean.