How to Stop a Dripping Two-Handle Bathroom Faucet

Begin by clearing the area under the sink to access the water supply lines. Locate the two shutoff valves, one for hot and one for cold, on the wall or floor. Turn the oval or round handles clockwise until they stop moving to shut off the water. Next, turn both faucet handles to the 'on' position to drain any residual water and relieve pressure in the lines. This confirms that the water is successfully shut off. Finally, place a thick towel or rag over the sink basin, making sure to cover the drain opening completely. This will protect the sink's finish from dropped tools and prevent any small parts from being lost down the drain.

Examine the faucet handle that is causing the drip. Look for a decorative cap, which is usually on the top or front of the handle and may have a red or blue indicator. Carefully use the edge of a small flathead screwdriver to gently pry this cap off, revealing a screw underneath. Using either a Phillips head screwdriver or an Allen wrench (depending on the screw type), turn the screw counter-clockwise to loosen and remove it. Set the screw aside in a safe place. With the screw removed, grasp the handle firmly and pull it straight up and off the faucet body. If it is stuck due to mineral deposits, try wiggling it gently side-to-side while pulling up. Avoid using excessive force.

With the handle removed, you'll see the valve stem of the cartridge. There may be a decorative metal sleeve or dome (escutcheon) covering the valve body; unscrew this by hand. Now, you will see a large nut, often called a packing nut or retaining nut, holding the cartridge in place. To protect the faucet's finish, wrap the jaws of a pair of channel-lock pliers or an adjustable wrench with electrical tape. Grip the nut with the wrapped pliers and turn it counter-clockwise to loosen and remove it. Once the nut is off, grasp the plastic or brass stem of the cartridge with the pliers and pull it straight up and out of the faucet body. Note the orientation of any tabs on the cartridge, as the new one must be installed in the same position.

Take the old faucet cartridge, and any associated O-rings or seals you removed, to a local hardware or plumbing supply store. Having a picture of the faucet on your phone can also be very helpful for identification. Ask an employee in the plumbing department for assistance in finding an exact match for your parts. Faucet cartridges are highly specific to the brand and model, so a visual match is critical. While at the store, purchase the new faucet cartridge and a small tub or tube of heat-proof, non-toxic plumber's grease.

Before inserting the new part, use a clean rag to wipe out the inside of the faucet's valve body, removing any mineral scale, grit, or old rubber fragments. Next, take the new faucet cartridge and apply a light, even coat of plumber's grease to all of its rubber O-rings. This lubrication helps protect the seals during installation and ensures a watertight fit. Carefully align the new cartridge with the faucet body, making sure any tabs or notches line up exactly as the old one did. Press it firmly into place. Hand-thread the retaining nut back on clockwise to prevent cross-threading, then use your pliers or wrench to give it a final quarter-turn to snug it up. Do not overtighten.

Place the faucet handle back onto the new cartridge stem, ensuring it is positioned correctly. Re-insert the retaining screw and tighten it clockwise with your Phillips screwdriver or Allen wrench until it is snug. Push the decorative cap back into place over the screw until it clicks. Go back under the sink and slowly turn the shutoff valves counter-clockwise to restore the water supply. Open the faucet handle you repaired to check that water flows properly. Then, turn the faucet off and carefully observe the spout for several minutes. Also, inspect the base of the handle and under the sink for any signs of leaks. If everything remains dry, you have successfully fixed the drip.