How to Repair a Compression Faucet

Shut off the Water Supply

Look for a small shutoff valve (usually with a football-shaped handle) on the water line under the sink. Turn the handle clockwise to close the valve. If there are no shutoff valves under the sink, turn off the water supply to the house at the home's main shutoff valve or the water meter. Once the water is shut off, open the faucet fully to release any pressure and residual water in the line.

Remove the Faucet Handle

The handle body is attached to the faucet valve stem assembly by a screw concealed under a decorative cap. The cap on older faucets is often metal and screws into the handle. To gain access to the screw holding on the handle, grip the cap with pliers and unscrew it. If the cap is plastic, use a small flat-blade screwdriver to pry off the cap.

Some faucets have metal caps that also pry off. What's the best way to tell? If the metal cap has serrations around the perimeter, it's probably a cap that screws off. If the cap is thin or has a smooth edge, it most likely pries off.

Remove the screw that holds the handle onto the valve stem, using a Phillips screwdriver. Pull the handle straight up to remove it from the stem. If the handle is stuck, you may need to use a compression faucet handle puller to remove it.

Remove the Valve Stem Assembly and Cover (if present)

Once the handle is removed, you might find a cover over the valve stem assembly (especially with single-handle faucets, commonly found on tubs and some sink faucets). Remove the valve stem assembly cover by unscrewing the knurled knob that holds it on, using pliers.

If there is no cover, look for a hex-nut section of the valve stem assembly, usually located where the assembly meets the faucet body. Use pliers or an adjustable wrench to grip this nut and turn it counterclockwise to loosen the valve stem assembly. Unscrew the valve stem assembly all the way and pull it out of the faucet body.

Remove the Stem Washer

Locate the old washer on the bottom end of the valve assembly, sitting in a valve seat. It will be held in place with a screw, and it will likely be well worn or deformed. Remove the brass screw holding on the washer. Stick a small flat-blade screwdriver into the hole in the washer to pry it out of the valve seat. Clean the end of the washer holder of any deposits or residual rubber so that the new washer sets cleanly into the valve seat.

Find a Replacement for the Old Washer

You may need to buy an assortment of washers, often sold as a "faucet repair kit." If desired, you can also get a replacement for the rubber O-ring around the valve stem assembly.

Push the replacement washer into the valve seat, and secure the washer with the brass screw. Replace the O-ring, as applicable. Coat the outside of the O-ring (old or new) with a thin coating of waterproof plumber's grease.

Reassemble the Faucet

Thread the valve stem assembly into the faucet body, and tighten it securely with pliers. Reinstall the handle and cap. Turn on the water supply, and check the faucet for leaks.