Turn off the water supply to the tub
Cover the drain with a stopper or cloth
Plug the overflow opening if needed
Remove the faucet handle
Remove the trim plate or escutcheon
Take out the stem or cartridge
Inspect the washer, O-rings, and seals
Replace worn or damaged parts
Clean mineral buildup from the valve body
Apply plumber’s grease to moving parts
Reinstall the stem or cartridge
Reattach the trim plate and handle
Turn the water supply back on
Test the faucet for leaks
Replace the entire faucet assembly if repairs do not stop the leak