How to Fix a Leaky Faucet

Four common types: (1) Cartridge — single-handle that lifts up/twists; replaceable cartridge inside. (2) Ceramic disc — high-end single-handle, two ceramic plates that slide; rarely fails. (3) Ball — single-handle with a rotating chrome ball under the cap; common in older Delta kitchen faucets. (4) Compression — two-handle (hot/cold separate) with a rubber washer at the seat; most common in pre-1980 homes. The repair part is different for each — buy the right one or you're going back to the hardware store.

Under the sink, two shutoff valves (hot and cold). Turn both clockwise to close. Turn on the faucet to drain residual pressure — water should stop completely. Plug the drain with the stopper or a rag — losing a tiny screw down the drain is the most common repair mistake. Have a towel for the inevitable water leftover in the lines.

Cartridge faucets fail when the rubber seals inside the cartridge wear out. Repair: remove the handle (usually one screw, sometimes hidden under a decorative cap), pull out the cartridge with pliers (or the manufacturer's cartridge puller), drop in a new cartridge of the EXACT same model, reassemble. Brand-specific: a Moen 1225 cartridge goes in any Moen single-handle; a Delta cartridge is different. Bring the old one to the hardware store for matching.

Ceramic disc faucets rarely fail, but when they do it's usually mineral buildup between the discs causing slow flow. Sometimes a worn O-ring causes drips. Remove the handle, the chrome cap, the metal collar; lift out the ceramic disc assembly. Clean with vinegar OR replace if the discs are cracked. Replacement parts are usually faucet-brand-specific.

Old Delta and Peerless single-handle kitchen faucets use a ball-type valve. The repair kit includes a new ball, cam, springs, seats, and O-rings. Take the faucet apart (handle off, dome cap, cam assembly), replace EVERY rubber piece (don't reuse old O-rings even if they look OK — they're $0.50). Reassemble. ~$15 fix.

Compression faucets (separate hot and cold handles, old-school) have a rubber washer that compresses against a brass seat when you close the tap. The washer wears out; the seat sometimes pits. Remove the handle and packing nut, lift out the stem, unscrew the brass screw at the bottom of the stem, replace the rubber washer with the same size (sizes are tiny and visually similar — bring the old one). If the seat is pitted, use a seat wrench to remove and replace it.

Apply a thin smear of plumber's silicone grease (NOT Vaseline, not 'plumbers putty', not generic lubricant) on every rubber O-ring and washer before reassembly. The grease lubricates assembly so you don't tear the rubber, and it provides a long-term seal. Petroleum-based lubricants degrade rubber — silicone grease is the right product.

Plumbing supply-line connections, threaded plugs, faucet bases against the sink — these need PTFE tape (white plumber's tape) wrapped 3-4 times clockwise around the male threads before assembly. The tape fills micro-gaps and prevents drips at threaded joints. Wrap clockwise so tightening doesn't unwrap it. Don't use PTFE tape on rubber-sealed connections (compression fittings, faucet O-rings) — those don't need it.

The most common repair failure: over-tightening packing nuts. Cracks ceramic discs, strips brass threads, splits washers. Tighten to hand-tight plus 1/4 turn with the wrench — NOT 'as tight as you can get it'. If there's still a drip, the wrong fix is more torque; the right fix is to take it apart and check seals.

Turn the supply valves slowly back on. Watch for leaks at every connection (supply line, base, handle). Run the faucet through full hot, full cold, mixed, multiple cycles. Look at the spout 30 seconds after shutoff — that's when slow drips appear. Look under the sink for moisture — a slow leak under there shows up as warped cabinet floor weeks later.

Cartridge faucets under 10 years old: repair. Cartridge faucets over 15 years old: consider replacement (the supply lines and seal points beyond the cartridge are degrading too). Faucets where the chrome plating is peeling, the handle is loose at the base, or the spout swivel is leaking from the base — replace, don't repair. A full faucet replacement is $80-300 in parts and 2 hours of work.