Replacing Tap Washers: When It Is Still the Answer

Does your tap even have a washer?

Turn the handle from fully off to fully on and count. If it takes more than one full turn and you can feel it squeeze tighter as you close it, the tap is a compression tap and it closes by pressing a rubber washer down onto a brass seat. That washer is the part that wears, and it is the cause of most drips from older pillar taps and the separate hot and cold taps found in period bathrooms.

If the handle moves a quarter or half turn and stops dead, the tap has ceramic discs. Two polished ceramic plates slide over each other to open and close. There is no washer to change, and a drip means the cartridge is scored or scaled up. Single-lever mixers that move up and down and side to side use a ceramic cartridge too. For those, go to the guide on a leaking mixer tap instead, because the fix is a matched cartridge, not a washer.

Some older mixer taps with two handles and one spout still use washers in each handle, so apply the turn test to each side separately.

Where the water comes out tells you which seal failed

A compression tap has two seals, and they fail in different ways. The washer on the bottom of the jumper stops water coming out of the spout. The O-ring or gland packing around the spindle stops water coming up past the handle. Mixing them up is the most common reason a new washer does nothing.

• Drip from the spout when the tap is off: the jumper washer or a worn seat.
• Water seeping out under the handle or round the shroud while the tap is running: spindle O-ring or gland packing. See the guide to a tap leaking from the handle.
• Water under the basin or sink, not at the tap: the tap tail connector or the isolation valve below it, which is a different job again.
• Tap that will not close at all however hard you turn: the washer has split or come off the jumper, or the headgear threads have stripped.

How to change a tap washer

Buy washers before you start. Most basin and kitchen taps take a half-inch washer and most bath taps take a three-quarter-inch washer. Mixed packs of rubber and fibre washers with a couple of spindle O-rings cost a few pounds at any merchant. Hot taps are better with a firmer washer rated for hot water; a soft rubber one can deform quickly on the hot side.

• Turn off the water to that tap. Use the small isolation valve on the pipe under the basin (a screwdriver slot turned a quarter so the slot runs across the pipe), or the stopcock if there is none. On a tank-fed hot tap with no isolation valve, close the gate valve on the cold feed pipe running from the loft tank into the bottom of the cylinder.
• Open the tap fully to drain it and put the plug in so nothing falls down the waste.
• Prise off the index cap (the red or blue disc), undo the screw underneath and lift the handle off. Unscrew the shroud if there is one.
• Hold the tap body still with one hand or a second spanner and undo the large hexagon on the headgear. Without holding the body you can twist the tap in the basin and crack the fixing.
• Lift the headgear out. The washer sits on the jumper at the bottom, held by a small nut or simply pressed on. Replace it with the same size and type.
• Look into the tap body at the brass seat before you reassemble. It should be a smooth, even ring.
• Refit the headgear, turn the water back on slowly and check for drips at the spout and round the handle.

If the headgear will not move with steady pressure, stop. Forcing a seized hexagon on an old tap often shears the tap body or cracks a ceramic basin, and then a washer job becomes a new tap and possibly a new basin.

When a new washer is not the answer

Look at the old washer. If it is flattened with a clear groove cut into it, the washer was the problem. If it looks fine, or the new washer shows a deep ring after only a few weeks, the seat is the problem. Water forced through a tiny gap over months cuts a channel in the brass seat, and no washer can seal against a scored surface for long.

A seat can be ground flat again with a tap reseating tool, a hand cutter that screws into the tap body. It works on sound taps but removes metal, so it can only be done a few times. The other route is a tap conversion kit: replacement headgear with ceramic discs that screws into the existing body and turns the tap into a quarter-turn tap. Kits exist for most common British thread sizes and suit good-quality taps you want to keep, such as period-style bath taps. On a cheap or badly corroded tap, a new tap is usually the better buy.

Mixer taps are the other case where washers rarely help. If yours is a mixer, a professional leaking tap repair usually starts with identifying the cartridge, because they are specific to the tap maker and model.

What it typically costs and when to call someone

As a guide to market prices, washers and O-rings cost pennies each or a few pounds for a mixed pack. Replacement headgear or a ceramic conversion pair is typically in the region of £10 to £30. A new basin or kitchen tap runs from about £30 for a basic model to well over £100 for a branded mixer, before fitting.

A drip is annoying rather than urgent, and our page on how much water a dripping tap wastes puts a number on it. It becomes urgent when the tap will not turn off at all, when the isolation valve under it will not close or is leaking itself (see isolation valve leaking), or when water is getting into a cabinet or floor below. In those cases turn the water off at the stopcock and get the tap made safe. With us that means the £60 call-out at any hour, and the repair price is agreed with you on site before any work starts. If you just need it to stop for tonight, the steps in how to stop a tap leaking will hold it until morning.