It is important to know where your water shut off valves are located. You also need to make sure that the valves are in proper working order. Internal shut off valves are usually located behind toilets, refrigerators, wash machines, under kitchen and lavatory sinks, and above water heaters. If any of those items malfunction you can quickly shut off the water to isolate the problem and have a lower risk of water damage. There is also a main water shut off valve located outside on the main service riser. If the valves inside are not working or you can not locate the valve you can shut off the water to the entire house. Some town homes, condos, or apartments may not have service riser shut off valve if this is the case or if the valve is not working you can call your local water company emergency line and have them shut off the water at the meter.
Call your local plumber for a location and inspection of your shut off valves. Also test them regularly, after time the valves can corrode and freeze.