This project details how to fix a leaky shower faucet. The first step is to turn off the water supply to the shower by locating the shut-off valves under the sink or in the basement. If there are no shut-off valves, turn off the home's main water supply. Next, remove the shower handle(s). Two-handle faucets have a screw beneath each handle cap which can be removed using a screwdriver or Allen wrench. Then remove the old cartridge which involves removing a retaining clip or nut. Use pliers or an adjustable wrench for this step. Install the new cartridge by inserting and securing it with the retaining clip or nut. Finally, reassemble the handle(s) and turn the water back on. Check for leaks at all connections, tightening and retesting if necessary.