Even if a dripping bathroom tap in the bathroom doesn't drive you nuts, it does waste water. Common causes of leaks include worn washers, rings and seals, and loose or damaged fittings. Troubleshoot the cause of your leaking tap by determining what type of tap you have, observing where the leak is coming from and taking apart the faucet to examine internal parts.
Find out what kind of tap you have, if you do not know already. Knowing what kind of tap you have may help you determine where the leak is coming from and how to fix it. If you have a tap with a single handle that revolves on a ball-shaped cap, you have a ball tap. If you have a tap with a single handle that moves side-to-side on a cylindrical shaft, you have a disc tap. If you have two handles that turn to control the water, you have a compression tap. Worn rubber washers or loose packing nuts can cause leaks in compression taps. Ball and disc taps do not have washers; however, worn O-rings, or corroded balls, discs or seals may be causing the leak.
Look at where the water is coming from. If the water is coming from the base of a ball or disc tap, you may have a worn O-ring. If it is dripping from the handle of a disc or ball tap, the adjusting ring may be loose. Drips from the spout of a disc or ball tap may indicate problems with the disc or cartridge in a disc tap, or the cam and packing, or seats and springs of a ball tap. An accumulation of sediment in a disc tap can also sometimes cause leaks. If a compression tap is dripping around the handle, the packing under the stem may be loose or damaged. If it is dripping from the spout, a likely culprit is a damaged washer or seal.
Turn off the main water supply and turn on the tap to drain the standing water, then open up the tap and look inside. To open a disc tap, unscrew the setscrew at the base of the handle and remove the cylinder that houses the O-rings. To open a ball tap, unscrew the setscrew and remove the cam assembly and ball. To open a compression tap, pop the cover off the handles and remove the screw, using a screwdriver to remove the handle. Unscrew the packing nut to access the stem.
Look for any loose fittings that need tightening. Look for any damaged, corroded or stripped parts. Take damage parts to the hardware store to buy replacements. Clean any parts with gunk or sediment deposits. Use an Allen wrench, when necessary, to undo or tighten parts.
Parts diagrams of disc, ball and compression faucets are on many plumbing websites.