Faucet Repair

Locate the shut-off valves beneath the sink. Turn the handles clockwise until they are fully closed. If there are no shut-off valves under the sink, you will need to turn off the main water supply to the house.

With the water supply turned off, open the single handle of the faucet to the middle position (both hot and cold) to allow any residual water in the lines to drain out. Leave the handle in the open position.

Look for a small decorative cap or plug on the handle. Pry this cap off using a flathead screwdriver or a utility knife to reveal a set screw. Loosen the set screw with an Allen wrench or screwdriver (depending on the screw type) and lift the handle straight up and off the faucet body.

After removing the handle, you will see an escutcheon (a decorative dome-shaped piece). Unscrew this by hand or with pliers if it's tight. Beneath the escutcheon, there may be a retaining nut or cap that holds the cartridge in place. Unscrew this part, which might require a wrench or pliers.

Once the retaining cap is off, the cartridge should be visible. Some cartridges have a retaining clip that needs to be removed first, often with needle-nose pliers. Gently pull the cartridge straight up and out of the faucet body. If it's stuck, you may need to use a cartridge puller tool or gently rock it back and forth while pulling.

Examine the O-rings and rubber seals on the old cartridge and within the faucet body. If they appear cracked, brittle, or flattened, replace them. It's often best to replace the entire cartridge if O-rings are worn, as this is a common source of leaks. You can also clean any mineral deposits from the cartridge seat in the faucet body.

Ensure the new cartridge is correctly oriented according to the markings or the way the old one was positioned. Slide the new cartridge into the faucet body until it seats properly. If there was a retaining clip, reinsert it.

Screw the retaining cap or nut back onto the faucet body, ensuring it's snug but not overtightened. Reinstall the escutcheon, and then place the handle back onto the cartridge stem. Secure the handle with the set screw and replace the decorative cap.

Slowly turn the hot and cold water shut-off valves back on counter-clockwise. Turn them on only partially at first to check for leaks. If no leaks are apparent, open them fully.

Turn the faucet handle on and off, testing both hot and cold water flow. Inspect around the handle, spout, and under the sink at the valve connections for any drips or leaks. If leaks persist, you may need to re-examine the cartridge installation or check for other worn parts.