The valve is corroded internally and stuck in the open position.
Water shut off valve under sink not working.
No matter how much i turn the knobs the shutoff valve is not closing.
This is usually caused by the rubber seat inside the valve drying out or becomes coated with friction producing minerals after years without use.
Or maybe it s a multi turn valve and you only turned it a quarter turn because most shutoffs are just quarter turn.
If there s buildup visible on the water valve pour a little white vinegar on the valve and scrub the buildup away with a wire brush.
If it s a cold valve find the main water shutoff for the house usually.
Sometimes there s a nut on the valve stem to tighten it if the stem is loose although this doesn t sound like your problem because a loose stem usually means water is leaking right at the valve.
Not sure if the sink was rocking and just caused the connections to break or what.
A water supply valve that won t work or leaks when it is shut can be repaired.
Otherwise you ll might find yourself dealing with a much larger problem that your initial one.
The handle has nearly corroded away and it crumbles in your hand when you try to turn.
Anyway my problem starts with the shutoff valves not working under the sink.
Dwizum aug 8 19 at 12 51.
If you re fixing a hot water valve turn off the hot water outlet on the water heater.
The ones under the pedestal sink have the screws.
Method 1 first make sure that you shut off the water that supplies the valve you re going to be working on.
Prevent shutoff valves from freezing or becoming stiff by turning the valve on and off twice a year.
If the valve won t turn off the water or shut off completely it is likely tha.
Turn the larger hex nut at the base of the toilet valve counterclockwise using an adjustable wrench to disconnect it from the valve then pull the valve housing off of the copper water supply line.
It s always a good idea to exercise your shut off.
If you are working on older plumbing it is often difficult to turn off the water shut off valves under the sink or behind the toilet because.