The trap is a popular source of leaks beneath a bathroom sink, although a leak can originate from the drain tailpiece, pipe couplings, or from the pipes themselves. Repairing the link can call for a bit of twisting, patching, or in some cases, replacement. Replacement pipes can be obtained from a local hardware store. Its a job you can handle yourself after a bit of investigation in order to find the exact location of the leak.
Remove whatever bathroom products and other materials are being stored beneath the sink. Determine if the leak is coming from the rear of the tailpiece beneath the pop-up stopper. Place the bucket beneath the tailpiece. Examine the retaining nut that secures the horizontal pivot rod into the tailpiece. A loose nut will allow draining water to escape around the pivot ball out the tailpiece, onto the floor. Tighten the retaining nut with slip-joint pliers.
Turn on the faucet and determine if water still leaks from the tailpiece. Unscrew the retaining nut, using the pliers. Pull back the horizontal pivot rod from the tailpiece, which allows you to reach the rubber washer and the plastic gasket that flank the pivot ball. Replace the washer, the gasket, or both. Insert the pivot rod into the tailpiece, making certain that the rod end fits through the hole in the bottom of the stopper. Tighten the retaining nut with the pliers.
Determine if water is leaking around the curved trap beneath the sink. Place the bucket beneath the trap. Check the slip nuts, or couplings, that secure the trap on either end to see if they are loose. Unscrew the slip nuts and examine the rubber washers beneath that provide a watertight seal. Replace washers as needed and tighten the slip nuts. Do not over tighten. Hand tighten the slip nuts on a plastic trap. Hand tighten a metal slip nut, followed by one-half turn with the pliers.
Examine the trap for continued leaks. Place the bucket beneath the trap. Disconnect a still-leaking trap using the pliers, or a pipe wrench, and allow any water inside the trap to fall into the bucket. Install a new trap. The replacement trap will be equipped with the proper washers and slip nuts for installation.
Place the bucket beneath a leaking pipe under the sink. Shut off the sink's water supply. Wipe the pipe dry, using a towel. Tightly wrap plastic electrical tape around the spot on the pipe that leaks, looping around the pipe two or three times. Cover the leaking spot and 3 to 4 inches on both sides of it. This fix should contain the leak until you have the time to obtain and install a replacement pipe.