How do I replace a tap washer?
The step-by-step for changing a washer in a traditional compression tap, including what to do if the seat is damaged.
- Difficulty
- beginner
- Time
- 45 min
- Read
- 2 min
- Safety
- caution
Short answer
Turn the water off, drain the tap, remove the head and unscrew the valve body, then replace the rubber washer at its base. Take the old washer with you to buy the right size — 'half inch taps' use several different washer diameters.
A traditional tap seals by pressing a rubber washer onto a brass seat. When the washer hardens or splits, the tap drips. The part costs pence, and the only real complications are seized fittings and a pitted seat.
Safety
What you'll need
- Adjustable spanner
- Screwdrivers
- Replacement washers
- Cloth to protect the finish
- Penetrating oil (optional)
Step by step
- Turn off the water at the isolation valve under the basin, or the stopcock.Isolation valves have a slot for a flat screwdriver — slot across the pipe means off.
- Open the tap fully to drain it, and plug the basin.Plugging the basin is what stops screws disappearing down the waste.
- Remove the tap head — usually a screw under the hot/cold indicator cap, or a grub screw at the side.The cap normally levers off with a small flat screwdriver. They crack easily, so go gently.
- Wrap a cloth around the valve body and unscrew it with a spanner.The cloth stops the spanner jaws chewing the chrome.
- Take out the washer from the base of the spindle — it may be held by a small nut.Some are pushed on; some are retained. Note how it comes off.
- Take the old washer to buy an exact replacement.Guessing sizes wastes a trip. Take the part.
- Fit the new washer squarely and reassemble, tightening the valve body firmly but not brutally.Overtightening cracks the seat inside the tap body, after which no washer will seal.
- Turn the water on slowly and check for leaks at the base and around the spindle.Slowly, so a mistake shows as a trickle rather than a jet.
Tips
- If the tap still drips after a new washer, the brass seat is pitted. A tap reseating tool, or a washer-and-seat set with a plastic seat insert, fixes it.
- Replace both taps at once even if only one drips — it saves doing the whole job again in six months.
- Photograph each stage as you dismantle. Washers and spacers go back in a specific order.
Common mistakes
- Not testing that the water is really off — The isolation valve may be seized open. Always confirm by opening the tap.
- Overtightening on reassembly — It cracks the seat in the tap body and turns a pence repair into a new tap.
- Guessing the washer size — There are several standard sizes and they are not interchangeable.
Questions people ask
How do I know if my tap uses a washer?
Turn the handle. Several full rotations from off to fully on means a traditional compression tap with a washer. A quarter or half turn means a ceramic cartridge instead.
The tap still drips after a new washer — why?
The brass seat the washer presses against is pitted or scored. Use a tap reseating tool, or fit a washer-and-seat set that includes a plastic seat insert.