Look in several places around the home to find the main water shutoff valve, including the basement, the crawl space under the home or inside near the utility area. The shutoff valve is usually a wheel or a lever and functions as either a gate valve or a ball valve.
In most homes with basements, the water lines come through the basement floors or walls with the valves nearby. Homes containing basements and crawl spaces can have their valves in either area. If the home is on a concrete slab or has only a crawl space, the shutoff valve is usually inside under the kitchen sink or near the utility area containing the water heater. Otherwise, the valve is under the home in the crawl space near the kitchen or water heater.
In a basement, look for the water shutoff valve on the front wall of the building or near the furnace if the house has one. Inside the utility room of a home, look for the valve on an outer wall. Some homes have a secondary shutoff valve for fire sprinkler systems. Home owners should use the valves downstream of the sprinkler water lines for safety reasons, unless specifically accessing the sprinkler system line.