I just fixed a clog in my bathroom sink by taking off the p-trap. I had turned off the water valve beforehand, and when I was done I turned it back on. After this, all that came out of the faucet was a trickle. Turning the valve in the off position does not stop the trickle. When I first turned the valve off before taking off the pipe, the valve was not turned all the way left or right. It was in the middle, but the water flowed fine. When I turned the valve all the way to the right, the water shut off at the faucet. My apartment is pretty old. Is this valve most likely broken?
Being old plumbing, when you turned off the valve (which you did not need to do to work on the drain) debris probably broke loose in the water line. Turn the valve to the off position again. Disconnect the supply tube above the valve. Hold a rag over the top of the valve and turn it on and off a few times. this should tell you if there is a clog and may clear the debris out. Good luck.
if your water valve has a plastic handle it is probably striped. take the handle off and try using pliers to turn the valve this will tell you what you need to know.
Could be a 3-way valve. Try putting it back in the middle. If that doesn't work, it probably broke.
Like the first person said, put it back in the original middle position. It could be a ball type valve, meaning it has a ball with a hole in it. To the far left or far right the hole to allow water to go through would be against the pipe wall, not allowing water through. In the middle, the hole would be aligned with the pipe wall and let water through. If that doesn't work, it is likely broken, especially if the valve was wanting to stick hard beforehand or you felt a quick breaking feeling as you were turning it. Valves rarely totally break like that. But it can happen. My guess is you most likely have it in the wrong position. If it is broke, you'll have to turn the water off further up the line if you can or turn all of the water off if there isn't another shut-off valve to cut water pressure to the line. I would think there should be another shut-off valve some up the water line.
These valves aren't the best by any means, you can see that by looking at it. It's probably broken, always has been. You'll have to fine a third turn off somewhere, or turn the water off to the entire unit while the valve is changed. That's the only way your going to do it.
