A leaking bathroom sink faucet can be very wasteful. The U.S. Environmental Protection Agency estimates that some sink leaks can drip away as much as 10,000 gallons of water a year. Not only does that waste water, but it drives up your water bills. So as soon as you hear that tell tale drip of water, you should fix your leaking bathroom sink faucet at the earliest opportunity. It's the perfect project for the first time plumbing DIYer looking to get their hands wet.
Shut off the water supply for the faucet that is leaking. Look underneath where the faucet is installed for the water supply shut off valve. These are round or oval in shape and will have a hose leading up to the faucet above. Rotate the knobs clockwise to turn off the water.
Insert the edge of a flat-head screwdriver underneath the faucet handle screw cap. These are usually disguised as the "Hot" or "Cold" labels on top of the handle. Pop the cap off.
Remove the faucet handle screw with a Phillips screwdriver. Pull the faucet handle straight up and off.
Remove the packing nut with an adjustable wrench. This is the uppermost hexagonal nut located on the valve stem.
Unscrew the second hexagonal nut, which is the valve stem itself.
Examine the valve stem. If it is cracked, this is the cause of the leak and needs to be replaced. Clean off any calcium deposits on the stem with a nylon brush.
Turn the stem upside down and examine the rubber washer at the bottom. If this is torn or worn down, it will have to be replaced. To do this, unscrew the retaining screw at the bottom. Replace with a new washer and secure with the screw. Apply a thin coat of silicone grease to the bottom of the washer.
Apply pipe thread compound to the threads on the stem. Insert into the socket. Tighten with the wrench. Replace the packing nut and tighten.
Slip the handle back over the stem. Secure with the handle screw. Replace the screw cover.
Restore the water supply.