A burst pipe can release several gallons of water a minute. The single most useful thing a homeowner can know is where the main shut-off valve is, and whether it still turns. Finding it takes ten minutes on a quiet afternoon. Finding it for the first time with water coming through the ceiling takes much longer.
Where to look
If you are on town or village water, the supply pipe comes into the house from the street, usually through the basement wall or floor on the side of the house that faces the road. Look for the water meter. The main shut-off is normally right beside it, and there is often a valve on each side of the meter.
If you have a well, the pipe comes in from the well to a pressure tank. The shut-off is on the pipe near that tank. You can also stop the water by switching off the well pump at its breaker.
No basement? Look in the crawl space, the utility room, a closet near the water heater, or the garage, low down on the wall that faces the street.
If you cannot find it, the inspection report from when you bought the house usually says where it is.
The two kinds of valve
- A lever handle is a ball valve. A quarter turn closes it. When the handle lies along the pipe it is open, and when it lies across the pipe it is closed.
- A round wheel handle is a gate valve. Turn it clockwise, several full turns, until it stops.
Test it
Close the valve, then open a cold tap on the lowest floor. The flow should slow to nothing within a minute. Open the valve again afterwards, slowly.
Old gate valves are often stiff, and some have not been turned in thirty years. Work the handle gently back and forth. Do not force it. A seized valve can snap or start to leak at the stem. If yours will not turn, or will not fully stop the water, that is a job for a licensed plumber: a modern ball valve costs little compared with the damage it prevents.
Label it, and tell everyone
Hang a tag on the valve that says MAIN WATER SHUT-OFF. Show every adult in the house where it is, and anyone who looks after the house while you are away.
The smaller shut-offs
Most fixtures have their own valve, which lets you stop a leak without turning off the whole house:
- Toilets: a small oval handle on the wall or floor behind the bowl
- Sinks: two valves in the cabinet underneath, hot and cold
- Washing machine: two valves on the wall behind it
- Water heater: a valve on the cold pipe going into the top of the tank
- Outdoor faucets: often an inside valve on the pipe that leads to each one, which you should close before winter
The valve at the street
There is another shut-off near the curb, under a small metal cover. It belongs to the water supplier, and it needs a special long key. If your own main valve fails during an emergency, call your water supplier's emergency number and they can turn the water off from there.
When water is coming in
- Close the main valve.
- Open a cold tap on the lowest floor to drain what is left in the pipes.
- If water is near electrical outlets, a panel or appliances, stay out of it, and switch off the power to that area only if you can reach the panel safely.
- Take photos for your insurance company before you clean up.
- Then find a licensed plumber.