Which Kind of Faucet Is Dripping?

A faucet that drips once a second wastes more than 3,000 gallons of water a year, according to the US Environmental Protection Agency's WaterSense program. The repair is usually a part costing a few dollars and an hour of patience. What decides how you fix it is the kind of faucet you have, and that is worth working out before you buy anything or take anything apart.

First, identify the faucet

Most household faucets fall into four types, and the handles are the quickest clue.

Two handles that you turn several times, and that tighten firmly before the water stops: a compression faucet. These are the oldest design and the most likely to drip, because they seal by squeezing a rubber washer against a metal seat.

One lever that moves up, down and side to side over a rounded cap: usually a ball faucet, a design long associated with Delta.

One lever or two handles that move smoothly, with no hard stop: a cartridge faucet. The cartridge is a removable plastic or brass unit that controls flow.

A single lever over a wide, cylindrical body: often a ceramic disc faucet. Two hard ceramic discs slide against each other, and they rarely wear out, so a drip usually means a worn seal rather than a failed disc.

If you can find the brand name on the faucet, the manufacturer's website will usually show an exploded diagram and the exact replacement part. Many brands sell or send replacement cartridges directly.

What you'll need

• An adjustable wrench and both a flathead and a Phillips screwdriver
• An Allen key set, since many single-lever handles are held by a small hex screw
• The replacement washer, O-ring, cartridge or seal kit for your faucet
• Silicone plumber's grease
• A towel to cover the drain, so small screws can't disappear down it

The repair, step by step

1. Shut off the water. Turn the valves under the sink clockwise until they stop. If there are no valves, or they won't turn, shut off the main supply to the house. Open the faucet to drain what is left in the pipes.
2. Remove the handle. Pry off any decorative cap, then undo the screw beneath it, or the hex screw on the side of a lever. Lift the handle away.
3. Take photos as you go. A quick picture after each part comes off makes reassembly much easier.
4. Remove the working part. On a compression faucet, unscrew the packing nut and the stem. On a cartridge faucet, pull out the retaining clip and then the cartridge. On a ball faucet, unscrew the cap and lift out the ball, cam and the small springs and rubber seats beneath it. On a ceramic disc faucet, unscrew the disc cylinder to reach the seals underneath.
5. Take the old part to the store. Washers, O-rings and cartridges come in many sizes, and matching the old one in person is the surest way to get the right replacement.
6. Fit the new part. Coat rubber parts lightly with silicone grease so they seat cleanly. On a compression faucet, look at the brass seat the washer presses against. If it is pitted, a cheap seat wrench removes it, or a seat-dressing tool smooths it.
7. Reassemble in reverse order, using your photos, and tighten firmly without forcing anything.
8. Turn the water back on slowly and run the faucet for a few seconds to push out trapped air before checking for drips.

If it still drips

A drip from the spout after a new washer usually means a damaged valve seat. Water seeping from around the handle points to the O-ring or packing rather than the washer. A drip that comes and goes with water pressure, or a leak under the sink rather than from the spout, is a different problem, often a loose supply line connection.

If the faucet body itself is cracked or badly corroded, or the parts are seized and won't move without serious force, replacing the faucet is often quicker than repairing it. A plumber is the safer choice when shutoff valves won't close fully, since an old valve can fail as soon as it is turned.