Steps to prevent a leaky tap

A dripping tap is the most forgivable fault in a house and the most expensive one to keep ignoring. The drip itself looks trivial, often just a washer or cartridge that costs very little. What the drip does over months is the real cost: the stain it cuts into the basin, the limescale it grows, and the seep that finds the tap hole and swells the worktop underneath. Tightening it a little harder each night can turn something that was a washer into a whole tap that has to be replaced. This guide covers why taps drip, the habits that keep them from dripping, and where the DIY line sits.

Why a tap drips, mechanically

Nearly every drip comes down to one of three wear points. On an old two-handle compression tap it is the washer: a soft disc crushed against a brass seat every time the tap is closed, until it no longer crushes evenly and water creeps past. On single-lever taps it is the ceramic cartridge: two polished discs that slide across each other, and when grit or limescale scores the polish, they stop sealing. On either kind it can be the seats and O-rings: the small rubber rings that seal the joint where the spout meets the body, which harden and perish with age like any other rubber part.

The force used on the handle is often what starts the trouble. A tap needs a quarter-turn of intent, not a wrist of conviction. Hands close taps hard because a dripping tap seems not quite off, and that hard closing is what wears the washer flat and scores the seat, so the drip causes the tightening that causes the next drip. Breaking that loop is half of tap maintenance.

The habits that put replacement day off

• Close taps fully, once. Gentle but complete, with no extra tightening after a count of three. If it needs a second turn to stop the drip, the washer or cartridge is already worn and should be dealt with.
• Descale gently, and only the outside. A soft cloth and mild cleaner on the chrome. Abrasive pads scratch the finish and give limescale a foothold. Vinegar on a cloth can help with spout build-up, but do not leave plated finishes soaking in acid for long periods.
• Fix the first drip promptly. A washer or cartridge replaced at the first drip protects the seat. The same part replaced six months later has been sitting behind nightly extra pressure ever since.
• Isolate before anything else. Whatever you open, close the isolation valve under the sink or the stop tap first, then open the tap to release pressure before removing the headgear. If the stop tap itself is leaking, seized or failing to shut off, that is often a job for a plumber, especially on pipework you cannot isolate.

Replacing the washer on a compression tap

On a compression tap, replacing the washer is a reasonable DIY job for someone patient and comfortable with basic plumbing. Isolate the supply, open the tap to drain it, cover the waste plug so the head screw cannot disappear, undo the headgear nut, lift out the jumper, fit the new washer, and reassemble. Bring the old washer to a plumber's merchant: sizes are not standard across makes, and a washer that only looks about right will leak. The job should be handed to a qualified plumber if the headgear nut is seized or corroded, if the seat is scored and needs resurfacing rather than a new washer, if the tap is on a shared or uncontrolled supply that cannot be simply isolated, or if there is any doubt about the isolation valve holding.

One regulatory point worth knowing: the UK Water Supply (Water Fittings) Regulations 1999 govern water fittings and backflow prevention to protect the public water supply. In practice, when replacing tap internals, use approved replacement parts from a plumber's merchant or a supplier that lists the relevant approval rather than a mystery listing where the approval is not stated. WaterSafe-registered plumbers are trained in the Water Fittings Regulations and can advise on the right part. If in doubt, ask the supplier or a WaterSafe-registered plumber.

When a tap has earned its retirement

Sometimes the honest answer is that the tap is finished: a body so furred that a new washer makes no difference, a spout O-ring groove corroded oval, chrome worn through to pitted brass, or spare parts discontinued because the maker has stopped supporting it. At that point the drip is a message, not a fault. Replacing a tap involves more than the tap itself, because the isolation valve, the condition of the flexible connectors and the waste connections all affect how straightforward the job is.

What this guide does not cover

This guide does not cover thermostatic shower valves, monobloc tap fitting on thin or stone worktops, or any tap served by an unvented cylinder at mains pressure, where isolation and pressure release need to be done in the right order for safety as well as tidiness. A tap that drips only when another tap runs is not really the tap's fault: that points to pressure and shared runs, and it is a question for a qualified plumber rather than a parts order. For any work on unvented hot water cylinders, sealed heating systems or other regulated appliances, use a competent person.