Knowing where and how to shut off water to the entire house (or any part of it) can be very important in an emergency. That's why it is extremely important for all members of the family to know where the valves are and in which direction they should be turned to shut off the water.
One way to identify the valves is to have a tag on each valve indicating its function, that is, which fixtures or group of fixtures it controls. Valve identifying tags may be obtained from plumbing dealers. Many plumbers are glad to offer a valve tagging service to their customers or prospective customers.
Another method of identification is by means of valve chart. Because this is somewhat more elaborate, it is usually employed only for houses with several bathrooms. A drawing is made of the basement piping with all the valves indicated. The valves are numbered on the chart, and then tags with corresponding numbers are placed on the valves. Another idea, which aids in identification, is to paint the pipes a distinctive color.
Obviously, the most important valve in the house is the main shut-off valve for the entire plumbing system. This valve, generally located on the house side of the water meter, usually has a handle like a wheel. If it has not been used for many years, it may require a wrench to turn it. Because the easy operation of this valve in case of an emergency is so important, it is advisable to place a few drops of oil around the valve handle once or twice a year. This will prevent the sticking action of corrosion. The shut-off valve may be the ground-key type with a small hole bored in its side for draining the pipes after the water is shut off, or it may be a compression stop with a cap nut covering the drain opening. In either case, close the opening before turning the water off. Unless this is done, water will spurt with force.
Where no means has been provided for shutting off a drain opening, drive a small wooden peg into it until the pressure is relieved by draining the piping that is exposed.
In addition to the main shut-off valve at the meter, the well-plumbed house has individual shut-off valves on the branch lines leading to individual fixtures, groups of fixtures or equipment such as water heaters, water softeners, automatic washers, etc.
Many contractors, when installing plumbing fixtures, provide separate shut-off valves or stops for each individual fixture. These will be found on the supply lines below the fixture. These individual stops are a great convenience to regulate water flow in case of repairs as well as emergencies.