It depends on the source of your leak. It could be the drain pipe or the water supply line. Either way, locate the leak & tighten the nut. If this doesn't work then replace the washer, both water supply lines and drain pipes have washers, take it with you to the hardware store. To replace the washer on the water line, turn off the valve. How-ever if the leak is from the bottom of the faucet you would need a faucet wrench because it's nearly inaccessible, in which case you need a landlord or a plumber. Good luck.
