These inexpensive little valves rarely get used and when they do sometimes they leak.
Replace water shutoff valve under sink.
Cut the supply line with a pipe cutter leaving enough room between the escutcheon plate and the cut to allow installation of the valve fitting.
Turn on the water supply to the sink once the valve is back in place and the plumbing has been completely re secured.
If this happens to you you can simply replace the valve with a new valve that matches the old one.
If you have a gas water heater turn the knob to the pilot position.
Place a bucket under the old valve.
Open the faucet to drain the line.
Deburr the pipe with a deburring tool.
Fortunately a bad shut off valve is extremely easy to replace.
Replacing a shut off valve compression valve or angle stop may seem like a daunting task but it really takes less than 5 minutes.
There are two basic types straight stops and angle stops and these valves normally remain on and are seldom closed functioning maintenance free for years.
When cutting the supply line cut slowly and gently so.
Residential plumbing systems can contain several different types of water shut off valves that control water flow.
Turn off the next valve up the line which may be the main water supply valve.
At this point if water is still exiting the valve it will need replacement.
Prepare for valve replacement.
With a few household tool.
As the line fills watch out for leaks.
The main water shut off valve stops the flow to the entire home from the water meter while other water valve types shut off the water at individual appliances fixtures and faucets.
Shut off the water at the main shutoff valve.
Shut off the circuit breakers to an electric water heater.