A broken drain pipe is a recipe for water damage beneath your sink if it is not promptly and properly remedied. A severe failure of your drain pipe will require replacement. But if it's a minor leak caused by a broken seal, you can often repair the damage yourself without buying a replacement part by simply checking the seals on the drain pipe. Repairing the broken seal is simple, and it doesn't even require any tools, because the pipes are fastened by hand.
Ensure that the sink is dry, with no sitting water which would leak out during the repair process.
Fold a paper towel in half and wrap it around the drain pipe with your hand, near the base of the pipe.
Wipe up the drain pipe, then check the paper towel for signs of moisture, to confirm that it is the drain pipe which is leaking.
Loosen the fitting that is securing the pipe to the underside of the sink by hand. Using a wrench with PVC drain pipes runs the risk of cracking and destroying the pipe.
Pull down gently on the drain pipe to gain access to the rubber seal ring at the end of the pipe.
Adjust the seal ring so that it is flush with the perimeter of the PVC drain pipe.
Reinsert the pipe back into the fitting.
Tighten the fitting by hand.