Turn off the water supply under the sink
Open the faucet to release any remaining water
Plug the drain to prevent losing small parts
Remove the handle screw and take off the handle
Remove the decorative cap or trim if present
Take out the retaining nut or clip
Pull out the cartridge, ball, or stem assembly
Inspect the cartridge, O-rings, washers, and seals for wear or damage
Replace any worn or damaged parts with matching parts
Clean mineral buildup from the faucet body and components
Apply plumber’s grease to O-rings and moving parts
Reinstall the cartridge, stem, or ball assembly
Reinstall the retaining nut or clip
Reattach the handle and trim
Turn the water supply back on
Test the faucet for leaks
Tighten connections slightly if needed
Replace the entire cartridge if the leak continues
Replace the faucet if internal parts are corroded or unavailable