Your plumbing system has many different water valves. Knowing where the most important water valves are can potentially save you thousands of dollars. The main water valve controls the flow of all water into your home and must work properly to prevent damage.
First, find the main water valve. It's usually located on the lowest level of your home near the street. Test the valve to see if it turns off - there shouldn't be any leaks or running water even if a faucet is turned on. Create a large tag and label the valve with the words 'main valve,' hang it from the water valve handle and make sure all household members can find the valve before a flood occurs.
Another important location to know is the weakest link of your plumbing system. This is probably the rubber connecting hoses on your washing machine. These hoses can dry out, burst and allow thousands of gallons to rush into you home. To avoid this, be sure to turn off the water supply valves to the washer before leaving home for extended periods of time. If the water valves are hard to reach, have them replaced with a single-lever turn-off that operates both hot and cold water supply valves with a single switch.
A little forethought to identify and label your main water valve can save you from taking an unexpected bath.