Turn off the water supply to the faucet (shutoff valve under the sink or main supply if needed)
Cover the drain with a cloth or tape to prevent small parts from falling in
Identify the faucet type (compression, cartridge/ceramic disc, ball, or cartridge/tap-in style)
Remove the handle
Remove the packing nut or retaining clip (varies by faucet type)
Replace the worn internal part causing the drip:
Compression faucet: replace the rubber seat washer and/or O-ring
Cartridge/ceramic disc: replace the cartridge
Ball faucet: replace the ball, seats, and springs (and O-rings if worn)
Inspect the seat and valve area for corrosion or grooves
Clean mineral buildup using vinegar or a descaling solution
If the seat is damaged, re-seat it or replace the valve body (as needed)
Reassemble the faucet parts in the correct order
Turn the water supply back on
Test the faucet for leaks and adjust handle alignment if needed
If dripping persists, replace additional related seals/O-rings or the entire cartridge/valve assembly
If you can’t identify the faucet model or parts, take the old part to a hardware store for matching or contact the manufacturer