Turn off the water supply to the bathtub
Plug the drain to prevent losing small parts
Remove the faucet handle
Take off the escutcheon or trim plate
Inspect the cartridge, stem, or washer
Replace worn or damaged O-rings, washers, or cartridge
Clean mineral buildup from faucet parts
Reassemble the faucet
Turn the water supply back on
Test for leaks and proper water flow
Tighten connections if needed
Replace the entire faucet if parts are corroded or unavailable