How to Fix a Dripping Tap (and When to Replace It)

A single dripping tap can waste thousands of litres a year. Many drips are a simple washer or cartridge change you can do yourself, but some need a replacement or a professional. The trick is working out which fault you have before you touch a spanner. This guide covers the tap types, the tools you need, the step-by-step repair, and the point where a licensed plumber is the sensible call.

Which tap do you have?

Most tap repairs come down to three types of tap, and the fix is different for each one. A traditional washer tap has two handles and a rubber washer on the end of a spindle. Turn the handle and the spindle screws down, pressing the washer against a brass seat to shut the water off. When that washer wears, water slips past it and the tap drips. A ceramic cartridge tap looks similar from the outside but holds a ceramic disc cartridge instead of a washer, and two discs slide together to stop the flow. Ceramic taps last well, but once the cartridge or its seals fail there is no washer to swap. A mixer tap has a single lever or two levers and a cartridge that blends hot and cold water, and most kitchen mixers and many newer bathroom taps are this type. You can identify yours in a minute. Turn the handle slowly: a washer tap keeps turning until it stops, while a ceramic or mixer tap moves through a short, firm arc. Then watch where the water appears, because that points to the part that has failed.

Match the drip to the failed part

Where the water shows up tells you which part has given out. A drip from the spout while the tap is closed usually means the washer or the cartridge has worn, or the seat underneath it is rough. Water weeping from the base of the spout, or from under the handle, is normally an O-ring on the spindle rather than the washer itself. A drip that appears only while the tap is running can be a loose connection or a cracked body. On a mixer, a drip from the spout with the lever closed points to the cartridge, while water under the handle points to the cartridge seals. Drips at the base of a mixer where it meets the sink or the bench are usually a body O-ring or a loose fixing nut. Get this diagnosis right and the repair is quick. Get it wrong and you will change a washer that was never the problem, which is one of the most common reasons a tap still drips after a repair. If two or more faults are present at once, deal with them in the one visit rather than pulling the tap apart twice.

What a drip actually costs you

A dripping tap is rarely just noise. Depending on the drip rate it can waste anything from a few litres a day to thousands of litres a year, and every one of those litres is water you paid for. If the dripping tap is the hot side, you are also paying to heat water that runs straight down the drain. The waste shows up in other ways too. Constant moisture on a benchtop lifts sealant, stains stone and encourages mould in the cupboard underneath. A drip that runs down the tap body leaves mineral scale, which makes the chrome look tired and can seize the spindle over time. In a bathroom, a dripping tap keeps you awake at night, which is its own kind of cost. Fixing a worn washer costs very little and takes about half an hour. Leaving it for months costs far more than the part ever will, and it can be the difference between a simple washer change and replacing the whole tap because the seat has been damaged. If your water bill has crept up and you cannot see why, a dripping tap is one of the first things worth checking, along with a leaking toilet cistern.

Tools and parts to have ready

Have everything on the bench before you start, because you cannot duck out to the hardware store with the water off and the tap in pieces. You will need an adjustable spanner or a set of spanners, a screwdriver that fits the handle screw, pliers, a utility knife for lifting stubborn caps, a torch, a cloth and a small container for the parts. A tap washer assortment is cheap and useful, but the better habit is to take the old part with you and match it, because washers and cartridges differ in size, profile and material. If you have a ceramic or a mixer tap, buy the cartridge that matches your tap brand and model rather than a generic one, because an ill-fitting cartridge will leak or fail to shut off. Keep a tube of silicone plumber's grease for the O-rings, since it keeps them supple and helps them seal. Some washer taps need a seat reseating tool, so check the seat before you buy anything else. A bucket and an old towel under the sink will catch the small amount of water still sitting in the tap body.

Step 1: shut the water off and drain the line

Close the isolating valve under the sink, or the mains if there is no isolating valve, and then open the tap to drain the line. Never start work without shutting the water off, even for a job you expect to take five minutes. Opening the tap after you isolate proves the water is actually off and empties the tap body, so you are not working in a puddle. If the isolating valve is stiff or will not close fully, do not force it. A broken valve under a sink is a much bigger job than the tap repair you set out to do, and it leaves you with no way to stop the water. In that case, close the main supply at the meter instead and call a plumber to look at the valve. Plug the sink waste with a cloth or the plug before you start, so small parts cannot disappear down the drain, and put a towel in the cupboard below in case a little water escapes. If the tap sits on a wall body or is built in behind tiles, stop here and get advice before you pull anything apart.

Step 2: take the tap apart and identify the part

Once the water is off, take the tap apart carefully. On a traditional washer tap, flick off the index cap on top of the handle, undo the screw underneath it, pull the handle off and unscrew the bonnet nut. The spindle then lifts out with the washer at its base. Look at the washer first: a flat, cracked or grooved washer means you have found the fault. On a ceramic or mixer tap, remove the handle and the retaining ring, then lift the cartridge out, watching for any spring or clip that comes with it. Note the part you remove, including its size, its shape and any numbers stamped on it, and replace it with the matching one from a hardware store. Keep the parts in the order they came out and photograph each stage if you are unsure, because a tap put back together in the wrong order will leak or will not turn. When you fit the new washer or cartridge, everything goes back in the reverse order. Tighten the bonnet nut firmly but not aggressively, since overtightening crushes the new washer or distorts the cartridge and you will end up back where you started.

Step 3: fit the new part without damaging the seat

The seat is the brass face inside the tap body that the washer presses against, and it is where many DIY repairs go wrong. If the seat is scratched, pitted or scored, it tears the edge of a new washer within days and the drip comes back. Look at the seat before you fit anything. Clean it with a cloth and a little mild abrasive, then flush the tap body with clean water to remove the grit. If the seat is badly worn, a seat reseating tool cuts a fresh, flat face, and that tool has to match the size of the seat. Never attack a seat with a screwdriver or a drill, and never scrape hard in one spot, because you will cut a groove that no washer can seal. When the seat is flat and clean, grease the spindle O-rings with silicone grease, slide the new washer or cartridge into place and reassemble. Open the isolating valve slowly, let the tap run for a few seconds, then close it and watch for a drip before you put everything back under the sink. A tap that has stopped dripping cold can still weep once the water heats up, so check it again after a hot shower.

When replacing the whole tap is the better call

Repair is not always the cheapest option, and it is not always the one that lasts. A full tap replacement is usually more economical if the tap body is corroded, if the tap is leaking at its base, or if you have changed the washer more than once and it still drips. Older ceramic-disc taps can be hard to source parts for, so a tap that was repairable years ago may now have no replacement cartridge available at all. Other signs point the same way: chrome flaking away, a cracked or split body, a tap that moves on the sink because the fixing has failed, or a spindle that is seized or corroded. When you are already paying for a plumber's time, a new tap can cost less than the labour spent chasing an old one. Replacing a tap also gives you the chance to fit the mixer you actually want, add an isolating valve if there is none, and start again with a clean seat and a fresh cartridge. A replacement also saves you paying twice, because a repaired old tap that fails again means a second visit and a second call-out fee for the same problem.

When to call a licensed plumber

A washer or cartridge swap is a reasonable DIY task, and most homeowners can manage it in an afternoon. Stop and call a plumber if the isolating valve is stiff, if the leak is at a joint rather than at the tap, or if you are unsure at any point, because a small mistake here can turn into a flooded kitchen and the damage costs far more than the original repair. Some taps are not a DIY job at all. Concealed mixers, seized or corroded fittings, wall bodies and anything built in behind tiles need tools, parts and experience you are unlikely to have at home, and pulling them apart can damage waterproofing. That is where an independent plumber is the right call, whether the job is reseating a tap or replacing a concealed mixer, a wall body or a corroded spindle. Ask for a written quote before work starts so you know what is covered. If your job also involves a blocked drain, a toilet repair or a pipe repair, mention it when you book and the same visit can cover it. Leak detection is worth asking about if you can hear water running when nothing is turned on.