Remove the Old Faucet. If it's unclear when looking at the sink and faucet how many holes there are in the sink or vanity top, you will need to remove the old faucet. Turn off the water supply to the sink and use a basin wrench to unscrew the nuts holding the faucet in place below the sink.emove the Old Faucet. If it's unclear when looking at the sink and faucet how many holes there are in the sink or vanity top, you will need to remove the old faucet. Turn off the water supply to the sink and use a basin wrench to unscrew the nuts holding the faucet in place below the sink.