How to Fix a Dripping Faucet

A faucet drips from the spout after it is turned off. The cause is a worn cartridge, washer, or O-ring inside the handle. The part costs a few dollars to twenty, and the job takes about an hour including the trip to the store.

Shut off the water and release the pressure

Turn both supply valves under the sink clockwise until they stop. Open the faucet, hot and cold, and let it run dry. If there are no valves under the sink, shut off the main water supply to the house. Plug the drain with the stopper or a rag so screws and clips cannot fall in, and lay a towel in the sink.

Identify the faucet type

One handle that lifts and swivels is a cartridge or ball faucet. Two separate handles that turn several full turns are compression faucets, which seal with a rubber washer. Two handles that turn only a quarter turn are cartridge faucets with a cartridge on each side.

Remove the handle

Pry off the decorative cap on the top or front of the handle with a small flat screwdriver. Under it is a set screw, usually a hex (Allen) or Phillips. Loosen it and lift the handle off. Line the parts up on the towel in the order they come off, and take a photo at each stage.

Pull the cartridge or the compression stem

On a cartridge faucet, remove the retaining clip or nut with pliers and pull the cartridge straight up. It may be stiff; grip it with pliers and rock it. On a compression faucet, unscrew the packing nut and turn the stem out. On the bottom of the stem is a rubber washer held by a single screw, and there are O-rings around the stem body.

Match the part and replace it

Take the cartridge or stem to the hardware store and buy an exact match; there are hundreds of shapes and a near match will leak. For a compression faucet, buy a new washer and O-rings of the same size, or an assortment pack. Coat the new O-rings and cartridge seals with plumber's grease.

Reassemble and turn the water on slowly

Put the parts back in reverse order using the photos. Open the supply valves a quarter turn at a time with the faucet open, so air escapes without a bang. Turn the faucet off and watch the spout for a minute.

If the drip continues with new parts. The valve seat or the faucet body itself is corroded or pitted. A seat can sometimes be replaced, but a corroded body means it is time for a new faucet.