Repair a shower faucet that won’t shut off. Most single-handle, cartridge-style faucets can be repaired in an hour or less with basic tools.
Remove the handle - Turn off the water supply to the shower. Then pry off the handle cap with a small pocketknife to expose the internal handle screw. Turn off the water at the fixture shutoff valves or at your home's main valve. Turn on a faucet to make sure it's off. Remove the handle as shown in Photos 1 . If the handle sticks, try heating it with a hair dryer set on “hot”. If you still can't get it off, use a special handle puller—an inexpensive tool available from plumbing parts distributors or home centers.