Home Improvement Skills & Specialties Plumbing

How to Find the Main Water Shutoff Valve in Your Home for Repairs and More

A main water shutoff valve is used to shut down the incoming water for the entire house. In the case of a leak, it's important to know where the main water shutoff valve is located, what it looks like, and how to operate it. Otherwise, you may not have a way to control the leak while waiting for a plumber or picking up repair parts. Learn how to find the main water shutoff valve in your home in case of repairs, maintenance, or emergencies.

Common Main Shutoff Valve Locations

There are few common locations for the main shutoff valve: the basement, the crawlspace, the mechanical room, an exterior wall, or the yard.

Basement

Most main water shutoff valves are located inside the home, in the basement if it has one, just a few feet from where the main water line enters the house. Water supply lines usually run into the house from the street side of the property, so check any utility areas, like the laundry room or near the water heater, that are located along the side of the house that faces the street.

Crawlspace

Some properties may have a basement and a crawlspace or may just have a crawlspace. Depending on the layout and building construction, the main water line may run through the crawlspace before entering the home. There is a chance that the main water shutoff valve is in the crawlspace. If this is the case, consider having a second shutoff valve installed in the primary living space for easy access and convenience.

Mechanical Room

Homes that have a slab-on-grade construction do not have basements and don't usually have crawlspaces. In these situations, there is a high chance that the main water shutoff valve is located in the mechanical room near the water heater. It may also be found under the kitchen sink, or in a similar location.

Exterior Wall

If your home is in a warmer part of the country, there isn't the same need to bury the main water line deep below the frostline, so the main water shutoff valve may be located outside on an exterior wall. Check the outside of the house, starting close to the outdoor faucet to locate the main shutoff for the home.

The Yard

The exterior wall of the property isn't the only outside location for the main water shutoff valve. In some cases, the valve is installed underground in the yard. Look for an access panel buried in the ground. It will usually be located near the street, though there is a chance that the panel is covered in dirt and grass. The access panel may only house the curb stop valve, which should only be operated by trained individuals and those with permission from the local water utility company.

Main Shutoff Valve Types

Plumbing infrastructures use a variety of different valves to control the flow of water, but there are typically only two types that are used for main water shutoff valves in residential locations, including gate valves and ball valves.

  • Gate valves used to be a common option for residential homes, though they are not as durable as ball valves, which has led to most new homes making the switch to ball valves. Gate valves have a circular handle mounted on a stem, which is connected to the body of the valve. When the user turns the valve clockwise, it closes the gate inside the body of the valve to stop the water. Turning the valve counterclockwise will open the gate and restore the flow of water.
  • Ball valves are the best option for a main water shutoff valve because they are easy to use and considered more reliable than gate valves. A ball valve has a lever-style handle that attaches directly to the body of the valve. When the lever is rotated 90 degrees, it moves the ball inside the body of the valve to open or close the valve. If the lever is perpendicular to the water line, the valve is closed, but if the lever is parallel or in-line with the water line, the valve is open.

How to Find the Main Water Shutoff Valve

The exact location of the main water shutoff valve can differ between properties, so there is no universal spot where the valve is guaranteed to be installed. However, there are several methods you can use to find the main water shutoff valve at home.

Investigate the Basement or Crawlspace

Start the search by looking in the basement or crawlspace. This is the most common place to find the main water shutoff valve. It's typically located within a few feet of where the main water line enters the home. Given that the main water line for the house must branch off from the water main for the street, the water line usually enters the house through the side that is adjacent to the street.

Several water supply and drain line material types may exist in a home, including copper, rigid plastic, PVC, and others. The main water supply line will be copper, brass, or galvanized metal and may contain plastic parts. You may find cast iron or even lead piping if the plumbing infrastructure has not been updated in an older home. If the valve is in the crawlspace, it's recommended to install a secondary shutoff valve above the crawlspace in the main living area for better accessibility in case of an emergency.

Follow the Visible Water Lines

In some cases, the main water line may be buried behind drywall, paneling, or even flooring. If you can't find the main water line in the basement or in the crawlspace, check for visible water lines near the water heater. Once you have located the incoming cold water supply line attached to the water heater, you should be able to follow the pipe back to the main water line, where you will find the main water shutoff valve.

Work slowly and have a flashlight on hand in case you need to see where the pipe runs when it disappears behind a wall, under the floor, or in the ceiling. For slab-on-grade homes, there is a high chance that the main water shutoff valve will be in the closet where the water heater is installed.

Locate the Water Meter

The water meter is used to keep track of the exact water usage. Since it's typically used for billing purposes, it must be installed before the main water line branches in order to record 100 percent of the water usage. The water meter connects directly to the main water line and has a round shape with a glass or clear plastic face, allowing the homeowner to read the usage recorded on the dial.

After finding the water meter, check downstream of the device to find the main water shutoff valve. It should be located between the water meter and where the main water line connects to the home's network of water supply plumbing. In warmer climates, the water meter may be installed outdoors, instead of in the basement or crawlspace.

Inspect the Exterior of the Home

The main water shutoff valve will not be on the exterior wall of the house if the home is located in an area where the temperature drops below freezing. This is because the low temperatures would cause the water line to freeze, shutting off the flow of water, and causing damage to the water line.

However, in warmer locations, the main shutoff valve may be installed on the outside of the building. Take a walk around the house and check for any water pipes that feed into the ground. It will usually be located near the water meter on the street side of the property.

Look for a Panel in the Yard

When a leak occurs, the last place anyone wants to go looking for an emergency shutoff valve is the yard, but some homes will have the main water shutoff valve contained in a chamber, pit, or a shallow box. Head outside to check the yard for any signs of a plastic or metal panel in the ground. The panel should be able to be lifted up to reveal the main water shutoff valve below. You may need a wrench to open the panel, so make sure to have one on hand when you go looking.

Check the Property Inspection Report

If you can't find the main shutoff valve after checking inside and outside, then you may need to dig up the property inspection report that should have been completed when purchasing the home. The plumbing section of this report should list where the shutoff valve is located, and may even have a photo of the valve. Using this information, you should be able to track down the main water shutoff valve.

What to Do If You Can't Find the Main Water Shutoff Valve

In some cases, the home may not have a main water shutoff valve or you may not be able to find the valve. If this occurs, you should contact the local water department for help. Even if they cannot help locate the valve, the water department can shut the water off at the curb stop, allowing you or a hired plumber to install a main water shutoff valve for the home.

Another option is to contact a plumbing company that offers water line detection services. By tracking down where the main water line enters the building, they may be able to locate the main water shutoff valve or, at the very least, confirm that the home does not have a main valve.

FAQ
  • What is the best shutoff valve for a main water line?

    Gate valves used to be the most common option for a main water line, but they have a tendency to wear out, leading to a leak or seized valve handle. Due to this problem, ball valves are considered the best type of main water shut off valve.

  • What are the two main water shutoff valves?

    The two types of main water shutoff valves are gate valves and ball valves. Gate valves operate by turning the handle counterclockwise to open the valve and clockwise to close the valve.


    Ball valves operate by rotating a lever 90 degrees. When the lever is perpendicular to the water line, the valve is closed. When the lever is parallel or in-line with the water line, the valve is open.

  • How do you fix a leaking main water shutoff valve?

    If the main water shutoff valve is leaking, you can try to fix the issue with a set of channel lock pliers. Grip the packing nut of the valve and gently tighten it.


    Alternatively, the issue may be caused by a loose bleeder valve. Use your finger or the pliers to tighten the bleeder valve and check if the leak has stopped.


    If the leak continues, then you will need to replace the main water shutoff valve. Contact a plumber to shut off the water to the house and replace the valve.