How to Fix a Leaky Tap

A leaky tap is not one job. Spout drips, base weeps, and outdoor standpipes fail in different places, and the parts are not interchangeable. Spend five minutes diagnosing before you buy anything; the wrong “universal” cartridge wastes a trip and leaves the drip running.

Work out where it leaks

Dry the tap with a cloth. Run it briefly, then shut it and watch.

Under-sink light is usually awful. Use a torch before you strip anything: confirm there is an isolating valve on the flexi you are about to undo, and that the leak is not a wet connector dripping onto the cupboard floor while you blame the spout.

If the tap body is cracked, chrome is paper-thin, or you already know the valves are seized solid, skip repair and plan a swap: replace a kitchen tap or replace a bathroom basin tap.

Isolate before you strip it

1. Close the isolating valve under the sink or basin (usually a small lever or screwdriver slot on the copper or flexi). If there is none, close the main stopcock.
2. On a mixer, isolate hot and cold. One side left open will spray you the moment the cartridge lifts.
3. Open the tap fully and let residual water drain.
4. Put the plug in so handle screws cannot vanish down the waste.
5. Protect chrome with a soft cloth when you use a spanner.

If you cannot find the stopcock, stop and locate it properly before you open the valve body. Shared supplies in flats are a common reason to call a plumber rather than cut water to the whole landing.

Quick path once you know the type

Washer taps

Prise the indicator cap, undo the handle screw, wrap the shroud, undo the brass headgear, and swap the rubber washer on the spindle end. Seat it flat. If the brass seating inside the body looks deeply scored, a new washer may only buy days of quiet. Full walkthrough: how to change a tap washer.

Cartridge mixers

Note the cartridge orientation (flats or a tab often only fit one way). Undo the retaining nut, pull the cartridge straight up, and fit an exact match (brand and series matter more than “looks similar”). Detail: how to fix a dripping mixer tap.

Spout and outdoor routes

Bath spouts and outdoor taps are their own seal paths. Do not force a basin washer kit onto either. Use the spout or outdoor guide linked in the table above.

Common mistakes

• Buying a washer assortment and fitting one that is slightly too small. It weeps again within a week.
• Isolating only the cold on a mixer and opening the hot cartridge under pressure.
• Scoring the chrome shroud with a bare spanner because the cloth slipped.
• Treating every drip as a washer when the lever mixer has a sealed ceramic cartridge.
• Ignoring a wet flexi under the sink while chasing a “tap” drip that is actually a connector.

When to call a plumber

Call a plumber if you cannot isolate the supply, the tap body is cracked, the seating is too damaged for a washer, seized connectors will not undo without risking the pipework, or water still seeps after a correctly matched washer or cartridge. Flats with a shared stopcock you cannot operate safely are another clear stop.

FAQ

Is a dripping tap always a washer?

No. Traditional pillar and headwork taps usually use washers. Most modern lever mixers use ceramic cartridges. Bath spouts and outdoor taps often fail at O-rings or packing instead. Match the fault to the part before you shop.

Why does it still drip after I changed the washer?

Wrong size, debris on the seat, or a pitted brass seating. Clean the seat, match diameter and thickness exactly, and try again. Persistent drips on lever mixers usually mean the cartridge, not another washer.

Can I leave a slow drip overnight?

You can, but it wastes water and can stain enamel or leave a green mark on chrome. Isolate the tap locally if you have valves, then fix it when you have the right part rather than living with it for weeks.

When should I replace the whole tap instead?

When the body is cracked, threads are stripped, chrome is failing badly, or you cannot get a matching cartridge for an obsolete mixer. A full replace is often cleaner than stacking temporary fixes.