How to Stop a Leaking Bathroom Faucet

Dripping faucets aren't just an annoying sound that keeps you awake; they are a constant drain on your water bill and a silent destroyer of faucet finishes. Whether it is a slow weep or a steady stream, the fix usually hides right under the handle. Most modern bathroom faucets operate on a cartridge system, which is a modular piece that controls both water flow and temperature. Successfully repairing a leak is about patience and organization. You are dealing with small parts that vanish down the drain in an instant, so the first rule of this repair is to plug the sink basin. When done well, you will have a silent, smooth-operating faucet that shuts off completely with a single, firm turn.

1. Stop the Water Flow. Locate the water supply valves under the sink and turn them clockwise until they stop. Open the faucet handles to release any residual pressure in the lines.
2. Expose the Cartridge. Pry off the decorative cap on the handle to reveal the screw. Use an Allen wrench or screwdriver to loosen the set screw and lift the handle straight off the base.
3. Pull Out the Culprit. Use an adjustable wrench to loosen the retaining nut holding the cartridge in place. Once the nut is free, pull the cartridge straight up out of the faucet body.
4. Get the Right Part. Take the old cartridge to the hardware store to ensure you buy the exact replacement. Even if they look identical, small variations in diameter or stem length will cause the faucet to keep leaking.
5. Seat the New Cartridge. Clean any mineral deposits from the inside of the faucet body using a vinegar-soaked cloth. Slide the new cartridge into place, ensuring the notches align correctly with the faucet housing.
6. Verify the Repair. Tighten the retaining nut, replace the handle, and tighten the set screw. Slowly turn the water supply valves back on and check for leaks.