How to Fix a Dripping Tap: Washer, Cartridge and O-Ring

That steady plink in the middle of the night is one of the most annoying household noises, and it's rarely a sign of anything serious. Most drips come from a small rubber or ceramic part inside the tap wearing out, and swapping the part is a job many people can do with a spanner and a screwdriver.

I've pulled this guide together from repair advice published by Places for People, OVO Energy and AXA, so the order of the steps matches what UK landlords, energy firms and insurers tell their own customers. The first job is working out which kind of tap you've got, because the fix is different for each.

Why a tap starts to drip

OVO Energy says a drip is usually down to a worn washer or a worn tap seat, which is the surface the washer presses against to stop the flow. Over time that seat can turn rough, rusty or pitted, so it no longer seals. On mixer taps with a moving spout, Places for People says the small O-ring at the base of the spout is usually the culprit instead.

It's worth sorting out early. Places for People says a dripping tap can waste up to 5,500 litres of water over a year, and a leak left alone can contribute to damp and mould.

Washer tap or ceramic disc tap? The turn test

Both OVO Energy and Places for People suggest the same quick check: see how far the handle turns to reach full flow.

Tap type	How far it turns	What's inside	What usually wears out
Compression (traditional) tap	A full turn or more	A rubber washer	The washer, or the tap seat
Ceramic disc tap	About a quarter to half a turn	Ceramic discs in a cartridge	The disc valve (cartridge)
Mixer tap with a moving spout	Lever or handle	Often a cartridge, plus an O-ring at the spout base	The cartridge or the O-ring

AXA also notes that single-unit monobloc lever taps usually have a ceramic cartridge, and a broken cartridge is what causes the drip.

Tools and safety before you start

• An adjustable spanner, plus a flat-head and a cross-head screwdriver.
• Scissors, and replacement washers, O-rings or a new cartridge. Match the part to your tap's make and model.
• An Allen key or box spanner for some ceramic and mixer taps.
• A soft cloth or masking tape to protect the tap finish.
• A plug for the plughole so small parts can't disappear down the drain.

Turn the water off first. OVO Energy and AXA both say to use the isolation valve under the sink if there is one, or the stopcock if there isn't, then run the tap until the water stops. OVO also suggests wearing protective goggles. If you don't feel confident at any point, stop and call a plumber.

Fixing a dripping compression tap

1. Take off the cap or cover on the handle, unscrew the handle and remove the valve cover.
2. Loosen the valve with an adjustable spanner, holding the tap body steady with your other hand, and lift it out.
3. Undo the screw or nut holding the old washer and take the washer off.
4. Look at the tap seat. OVO and Places for People both say small channels or rust mean it's damaged. You can smooth it with a seat grinder, or fit a seat insert kit.
5. Fit the new washer, refit the valve, cover and handle, then turn the water back on and watch for drips.

Fixing a dripping ceramic disc tap

These have no washer to replace, so the repair means changing the cartridge inside.

1. Remove the tap head, called the headgear. It may lift off, unscrew by hand, or hide a small screw or Allen key fixing.
2. Unscrew the hexagonal nut at the neck of the valve with an adjustable spanner. It can be stiff, so hold the tap body or spout with your other hand to avoid straining the pipework underneath.
3. Lift out the ceramic cartridge and check it for damage or grime. Clean or replace it.
4. Reassemble in reverse order and test.

OVO Energy points out that cartridges come in left-hand and right-hand versions, so check which one you need before you buy.

When the drip comes from the spout of a mixer tap

If the water leaks from the moving spout rather than the nozzle, Places for People and AXA both point to the O-ring. The steps are:

1. Loosen the nut that holds the tap in place, using a box spanner from under the sink.
2. Turn the tap to face you and remove the small grub screw.
3. Lift the spout away to reach the O-ring at its base.
4. Cut or prise off the old O-ring and roll the new one into place.
5. Line up the spout, refit the grub screw and tighten the nut under the sink.

Mistakes that make a dripping tap worse

• Over-tightening. AXA, OVO and Places for People all warn against it. It can damage the joint or squash a washer so it fails sooner.
• Forgetting the water supply. Isolate it and drain the tap before you take anything apart.
• Fitting the wrong part. Take the old washer, O-ring or cartridge with you to match it.
• Losing track of the order. AXA suggests keeping parts in the order they came off.

If the tap still drips after you've changed the washer, seat or cartridge, both OVO Energy and AXA suggest the next step is a trained plumber.

A dripping tap and a running toilet have one thing in common

Both waste water around the clock without you noticing. If the tap's sorted and you can still hear water trickling somewhere, my guide on how to fix a running toilet covers the usual culprits inside the cistern.

If you work with plumbing and want to share what you know

Repair advice like this is only as good as the people writing it, and trade experience is valuable to readers who are stuck on a job.

Plumbers who enjoy writing can see plumbing blogs that accept contributor articles on this page.

Frequently asked questions

Is a dripping tap a plumbing emergency?

Usually not. It does waste water, though. Places for People says a dripping tap can waste up to 5,500 litres over a year, so it's worth fixing sooner rather than later.

How can I tell if it's a ceramic disc tap?

Check how far the handle turns. OVO Energy says ceramic disc taps reach full flow in about a quarter turn, while compression taps with washers need more than that.

Do I need to turn the water off to fix a tap?

Yes. OVO Energy and AXA both say to isolate the water first, using the valve under the sink or the stopcock, then run the tap until it stops.

Why does my mixer tap drip from the spout?

Places for People says the O-ring at the base of a moving spout is usually the cause. Replacing it often stops the leak.

What if the tap still drips after I change the washer?

Check the tap seat for rust or wear, as OVO Energy suggests. If it still drips after that, they say to call a trained plumber.