Every time you turn the water on or off, the tap washer is used. When the washer is worn, it may cause a drip that is not only annoying but can cause staining. Over time a good deal of water can be wasted. Worn tap valves will chew a washer, further shortening its lifespan. Various quality replacement washers are available, making it possible to upgrade so the repair won't have to be made as often.
Shut off the water to the tap.
Release water in the line by opening the tap.
Gently pry off the insert on the top of the tap knob with a small screwdriver to reveal the screw.
Loosen the screw with the proper screwdriver.
Remove the screw and lift off the handle.
Firmly hold the tap spout to keep it from turning and release the tap valve.
Undo the valve and remove.
Determine whether the valve has a washer retainer nut, and if so, remove it. If not, just pull the old washer over the central lug.
Replace the washer by the same method it was removed.
Reverse the steps to reassemble the tap.
Plug the sink before you start to keep parts from going down the drain.
If the faucet twists, the connection under the sink may become loose and leak.