How do you change a water valve in a bathroom?

To replace the water supply valve begin by turning off the water main that leads into the house. Then turn on the bathroom sink’s cold water next to the toilet to relieve the water pressure so when the valve is removed the amount of water draining is minimal.Click to see full answer. Also, how do you fix a water shut off valve?First shut off the water to the leaking water valve. Next remove the handle from the stem and then loosen and remove the packing nut. Remove the old washer and slide on the new one. Reinstall the packing nut, tighten lightly with a wrench (don’t over tighten at this or any other point) and reattach the handle.One may also ask, can a water shut off valve go bad? You can spend time rebuilding the old valve, but the problems will just reappear years from now. The best way to deal with bad valves is to replace them with modern quarter-turn ball valves. They rarely lock up, leak or wear out and best of all, they’ll take just an hour or so to install. Here’s how to put them in. Secondly, how do you know if a water valve is open or closed? When the handle of a ball valve is parallel to the valve or pipe, it’s open. When it’s perpendicular, it’s closed. This makes it easy know if a ball valve is open or closed, just by looking at it. The ball valve below is in the open position.How do I turn off the water to my bathroom sink? You turn off the water to the sink by closing the shut-off valve to the sink. Find the shutoff valves located on the pipe below your bathroom sink. Close the shut-off valves by rotating the knob in a clockwise position. Turn on the hot and cold water on the faucet attached to your bathroom sink.