If the leak doesn t stop after the first valve is turned off it s the other line that s leaking.
Fix leaky bathroom sink faucet single handle.
The part number of the replacement valves will vary depending on the faucet model number.
To identify your faucet model number please view identifying your faucet model.
Turn on water make sure the handle is in the off position then turn on the water by turning the knob under the sink counter clockwise.
To do that go under the sink and turn off the cold water at the wall by turning the knob clockwise.
Figure out which handle is leaking let s start by testing to see which side of the faucet hot or cold is leaking.
Identify your faucet model number.
Once you determine which side is leaking turn off both supply valves.
Decide which side of your faucet is dripping closing the water supply valves one at the same time.
Turn off the main water supply.
This will stop water from gushing out of your faucet when you unscrew it later.
Turn off the water locate the hot and cold water valves beneath the bathroom sink and turn the handle clockwise on both valves to turn off the water to your single handle faucet.
Alternatively look under your sink for a small valve.
Determine which side of your faucet is leaking by shutting off the water supply valves one at a time.
The issues should be resolved by replacing the valve cartridge.
Continuous leak when faucet is on or off.
To test to make sure the leak is fixed turn on the water and let it run for a minute.
Then turn on the faucet to release the pressure and remove any water that may remain inside the water lines and faucet.
Remove disassemble the old faucet.
Press the off switch on your water main box to turn off the water.
Turn it off and check if the faucet is still leaking.
Turn the faucet handles to on to release any remaining water.