How do I fix a leaky faucet without a plumber?

To fix a leaky faucet, first turn off the water supply valves under the sink. Then remove the faucet handle by unscrewing the decorative cap and the screw underneath it. Once the handle is off, you'll see the cartridge or stem assembly. The leak is usually caused by a worn washer, O-ring, or cartridge. Take the old part to a hardware store to find an exact replacement, then install the new part and reassemble everything in reverse order. Turn the water back on slowly and test for leaks. The whole job typically takes 30 to 60 minutes and costs just a few dollars in parts. Having an adjustable wrench, screwdrivers, and plumber's grease on hand will make the process easier.