how to turn water off under sink
Close the shut-off valves by rotating the knob in a clockwise position. Use your hand to tighten the shut-off valve. You don't want to over-tighten or you could damage the shut-off valve. Turn on the hot and cold water on the faucet attached to your bathroom sink. Allow any water that was stuck in the pipe between the faucet and the shut-off valve to drain out.