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.
Replace water shut off valve under bathroom sink.
Open the faucet to drain the line.
If you have a gas water heater turn the knob to the pilot position.
Turn off the next valve up the line which may be the main water supply valve.
Prepare for valve replacement.
Shut off the water at the main shutoff valve.
Place a bucket under the old valve.
If this happens to you you can simply replace the valve with a new valve that matches the old one.
Deburr the pipe with a deburring tool.
Under sink shutoff valves also called fixture shutoffs or stop valves allow you to turn off the water to the sink or other fixture without having to use the home s main shutoff.
When cutting the supply line cut slowly and gently so.
The water to a kitchen or bathroom sink is supplied through small copper or flexible neoprene tubes from a small control valve called a stop or shut off valve under the sink.
These inexpensive little valves rarely get used and when they do sometimes they leak.