As with compression faucets, worn parts are the most common causes of leaks. While these faucets to not have washers, they have o-rings, cartridges or ceramic discs that eventually wear and require replacement. Plumbers refer to all faucets other than those operating with compression washers as washerless. If one of these faucets starts to leak, repairs include replacing the worn parts.
Regardless of the type of faucet, repairs require turning off the water to the fixture. Most homes have stop valves near the floor that allow owners to turn off the leaking faucet without interrupting the water to the rest of the home. If the home does not have these valves, repairs require turning off the water main for the whole house. Open the valve to relieve any remaining water pressure before proceeding.
Accessing the worn part requires removing the faucet handle. On two-handle faucets, remove the decorative cap from the control lever and the screw from the stem in order to lift the handle off the faucet. Single lever faucet handles have an Allen screw located on the back of the control lever. Turn it fully left or right to access the screw. Remove the ball, cartridge or disk and replace the defective part before reassembling the faucet and turning on the water.