When a home's water supply system leaks or a repair to one of the plumbing fixtures is needed, you'll have to shut off the water. It's best to do this at the valve that's closest to the problem. That way, the rest of the house will still have a functioning water supply.

For a faucet, toilet, or similar fixture, first look for a stop valve that's connected to the water supply tubes, located directly under the fixture. This is normally a chrome-plated or plastic valve; beneath sinks, one serves hot and one serves cold.

Turn the handle clockwise to shut it off. If this is too difficult to turn by hand, try wearing a work glove or gripping the handle with a pair of slip-joint pliers.

If you don't find a shutoff valve there, you can shut off the valve that controls the flow of water to the entire house, normally located near where the cold water pipe enters (outside in warm climates, inside in cold climates). In some cases, this valve is located on a pipe right before the water heater. In some cases, this valve has a red handle. To turn it off, rotate the handle clockwise.

To turn off the water both to your house and to the rest of your property (including outdoor sprinkler systems, hose bibbs, and so forth), look for the main valve just to the house side of your water meter, which is normally out by the street--often in a concrete box just below ground level. Once you locate the valve handle, turn it clockwise until it stops. If it is frozen in position, put a few drops of lubricating oil around the valve stem and wear a work glove to turn the hanlde or, if necessary, turn it with the help of a pipe wrench. This valve should always be completely open or completely closed--never used to control the amount of flow into the house.