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Property Types & Construction

Main Water Shut-Off Valve

Definition and meaning of Main Water Shut-Off Valve in real estate.

The main water shut-off valve is the primary control valve that stops the flow of water from the public water main or private well into a building's plumbing system. Knowing its location is critical for preventing extensive water damage during an emergency leak or home repair.

In more detail

This valve is typically located in the basement, crawlspace, utility room, or outside in a concrete box near the street. Homeowners should test this valve periodically to ensure it is not rusted or stuck in the open position. Shutting off this valve is a standard precaution before leaving a property vacant for long periods, especially in the winter when pipes can freeze and burst.

There are different types of valves, including gate valves and ball valves, which operate differently to stop the water flow.

Key facts

CategoryProperty Types & Construction
Common locationsBasement, crawlspace, utility closet, or near the water meter
Types of valvesBall valve (lever handle) or gate valve (round wheel handle)
Applies toAll residential and commercial properties with running water
Example

A pipe bursts in the upstairs bathroom, and the homeowner quickly runs to the basement to turn the main water shut-off valve, stopping the flood and saving the floors from damage.

Frequently asked questions

How do I find my main water shut-off valve?

Look near the perimeter walls of your home on the side facing the street or water meter. It is often located where the main water line enters the foundation, frequently near the water heater or in a utility room.

Which way do I turn the valve to shut off the water?

For a gate valve with a wheel handle, turn it clockwise to close. For a ball valve with a lever, turn the handle so it is perpendicular to the pipe to shut off the water.

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