Replace the cartridge, O-rings, or washer (varies by faucet type). Turn off water supply before disassembling.

Leaks are often due to worn-out O-rings, cartridges, or washers. Turn off the water, disassemble the faucet, and replace the faulty part.

Basic tools include an adjustable wrench, basin wrench, plumber's putty, Teflon tape, screwdrivers, and a bucket for water drainage. A flashlight and towel are also helpful.