Shutting off water to the whole house means operating the main indoor supply valve or, in some homes, a valve near the meter. During a major leak, close the accessible valve in its intended direction, open a faucet to confirm flow falls, and do not force a corroded valve that could break.
Use the accessible indoor main shutoff when available
It is often located where the water service enters the home, near a meter, basement, garage, or utility area. A lever valve typically closes with a quarter-turn until perpendicular to the pipe, while a wheel valve takes several turns.
Close the valve firmly without forcing a seized valve
If the valve will not move with reasonable hand pressure, do not use a large lever that could snap the stem. During an emergency, call the water utility or a plumber if the main shutoff does not work.
Open a faucet to confirm the supply is off
Flow should fall as pressure drains from the plumbing. Water can remain in pipes and tanks; strong continuing flow suggests the wrong valve was closed or the main valve is not sealing.
Address appliance energy sources if a leak reaches equipment
If water reaches water heaters, boilers, or electrical equipment, do not approach wet connections. Shut off energy only from a dry, safe location and get help if water is near the panel or energized wiring.
Sources
- U.S. Environmental Protection Agency WaterSense — Home Maintenance — Household maintenance related to water, leaks, toilets, pressure, and efficient use.