Open all the faucets, after 5 mins, it should stop. If it runs continuously, the main shut off valve leaks. That's not good. You need to shut off the water at the street and replace the valve.
Either the main valve wasn't shutting off completely, or more likely, you're just draining the system, especially if you have plumbing above in higher stories. If this is the case, it should stop after a while.
Once you have both shut off valves turned, no water should be entering your home and the main leak should stop as soon as your pipes finish draining. If you notice water still leaking several minutes after you've shut off these valves, you may have a malfunctioning shut off on your hands.
When the internal components of the tap, like the washer or the valve seat, wear down, they might not close properly, which can lead to the water not fully shutting off or even turning back on slightly when the tap is at 100% off.
Fixing a Stuck Water Shut Off Valve
We recommend putting a cloth over the handle and using your hand to slowly rock the stuck valve back and forth to loosen it. Keep doing this until the valve can be completely opened and closed. If the valve won't turn after trying this, grab a pair of Channellock pliers.
The Shut Off Valve Dripping or Leaking Water
Try tightening the valve's packing nut and then turn the valve off and back on a few times. If the dripping continues, contact a professional plumber for help.
Immediately after you turn off the main water valve, turn on a tub or sink faucet to its highest level, for both hot and cold connections. This relieves the pressure in the plumbing lines, and also ensures a full shut-down. Continue to open faucets around the house to drain down the home.
Does shutting off the water affect the water heater? When you go on vacation, it's best to also turn off your water heater, as well as the main water supply. Turning off the source of the heat (gas, electric) while you're away will not damage your water heater.
REASONS WHY YOUR TAP ISN'T TURNING OFF
This is most likely caused by corrosion, which tends to occur over time. In this situation, the best thing to do is entirely replace the tap handle. Even if it's just one tap that's the problem, it's recommended that you replace both of them at the same time.
In most instances, the rubber washers have become porous due to limescale build-up. You can replace the washers easily, and usually without professional help. In the case of a tap with a twin-lever fitting, the cause could also be a dirty valve bonnet. Avoid the temptation to simply turn the dripping tap even tighter.
The last thing that affects shut-off valve replacement costs is where you want to install the new valve and how easy it will be to reach there. The average cost to replace a water shut-off valve is between $375 and $600.
Pipes: Turn off water supply to the house and drain pipes to protect them from freezing. You can empty pipes by running the water and flushing the toilets after the water has been turned off. After draining the pipes, it is a good idea to leave the faucets open to prevent pressure build up from any water that remains.
WSSC suggests running all COLD water taps for about five minutes or until the water runs clear. Begin with the lowest faucet in your home or business and then open the other faucets one at a time, moving from your lowest floor to your highest.
If your faucet is dripping water after it is shut off, this may be indicative of a loose or damaged seat washer. Issues with washers is common in sink faucets leaking. The seat washer screw can become loose from repeated use, causing the faucet to drip water or chatter.
When it comes to plumbing, leaks are never a good sign, especially regarding a shut-off valve. A leaky valve is a clear sign that something is wrong. It might be something that can be repaired, or it may be something that an expert plumber has to replace. The sooner you fix a leak, the better.
Most of the time, homeowners are responsible for replacing a main water shut-off valve. This is because the property owner also owns the water service line from the shut-off valve near their property line to their house. That means they must maintain, repair, or replace it when needed.
The most common causes tend to be: The tap handle is stuck or corroded. The tap needs a new washer. The valve or tap body is broken.
There are three reasons why your faucet won't turn off:
Your faucet's handle is stripped and needs to be replaced. Your handle's stem needs a new washer. Your handle's seat needs to be replaced.
If you are trying to replace your kitchen tap(s) or carry out maintenance or repairs to your sink then you can simply isolate the taps instead of turning off the water completely. To do this you should see isolation valves for each tap that will be marked red for the hot tap and blue for the cold tap.
All of the pressure in your house water comes from the main water valve. As soon as you shut that off, the pressure stops. There is water in the pipes, but no pressure on it, like a full bucket. Open any faucet, and there's nothing pushing on the water.
If you shut off the water to your house you should also shut off the water to your water heater. Doing so will avoid any damage to the components of your water heater. Call your HVAC servicer or a plumber to walk you through the steps of shutting down your particular water heater system.
There may be a hidden plumbing leak in the walls of your home, or maybe your toilet is running when it's not in use. These “hidden” leaks can cause your home to be using water even when your main water valve is turned off.
Many people tend to think they can turn their water back on by themselves after it has been shut off. However, this is not the case. If your water has been shut off due to a late payment, you can not turn it back on by yourself legally. If you are caught doing so, there will be legal action.