How and Where to Find Your Main Water Shut off Valve

Where is the Main Water Shut Off in a House?

If you need to carry out plumbing repairs in your house or there is a leak and you need to immediately turn off the water, you need to know where the main water shut off valve is located.

Different fixtures in your house have separate shut off valves but there is a main shut off valve that shuts off water to the whole house. This valve could be located inside the house but in some instance it could also be located outside the house.

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Your main water shut off valve is usually located in the basement, crawlspace, garage or utility room near the water heater. In warmer climates, the valve could also be located on an external wall where the main water line enters the house from the street.

If the shut off valve is located inside the house, it will be very close to the wall facing the street. Think about it. The main water line from the city water is buried in your front yard so it only makes sense for the shut off valve to be installed in that side of the house.

In most cases, the main shut off valve will be installed very close to the water heater. Since you need hot water in the entire house, water heaters are installed very close to where the main water line enters the house.

The main shut off valve will therefore be located just before the water heater’s cold water supply pipe.

In instances where the shut off valve is located outside the house, it will be on the external wall outside of where the water heater is installed. It could also be very close to the street near the water meter.

To turn off the main water shut off valve, you will need to turn the valve all the way clockwise if you have a gate valve (with a wheel handle). If you have a ball valve (operated by a lever), turn the lever until it is at 90 degrees to the water supply pipe.

In most houses, the main water shut off valve is located in the basement. For houses built on a concrete slab the valve will however be located in the garage or basically very close to where you have the water heater, usually in a utility room.

If you can’t find your main water shut off valve in your basement, crawlspace or garage, look for it on an outside wall or very to the outside faucet. The faucet could also be located under your kitchen faucet or near the street next to the water meter.

The following is a guide on how and where to locate your main water shut off valve:

1. Locating the Main Water Shut Off Valve Inside the House

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Main water shut off valves are located inside the house especially in areas where freezing is a big concern. It is also easy to access them if need be.

If your house has a basement or crawl space, that is where your main water shut off valve will most likely be located. As I have already mentioned, that is where your water heater will be installed as well. And main shut off valves are always very close to the water heater.

Once in the basement, look for where the main water line enters the house. This could be on the wall facing the street or from the floor. Either ways, the valve will be found very close to where the main water line enters the house which is on the wall facing the street.

Remember that the main water line connecting your house to the city water is installed in a straight line from the street to the house. You therefore want to look for the valve close to that wall.

In most cases, the valve will be high off the floor, usually at eye-level or even higher. It could also be very close to the basement floor. There is no standard for where or how these valves are installed.

Main shut off valves are in most cases installed next to the water meter or pressure reducing valve. You may even find all the 3 plumbing parts in one place.

A pressure reducing valve (PRV) is a dome-shaped brass valve that is used to adjust the water pressure to your house. Knowing the location of this valve is also important just in case you need to reduce the water pressure in your house.

If your main water shut off valve is located in a crawlspace that is not easily accessible, you may want to have a plumber install another valve for you in area that is easily accessible. Close to the water heater will be ideal.

Note: Do not mistake the water heater cold water shut off valve with the main shut off valve. You should only turn off that valve if you have a leak in your hot water lines or if you need to replace or flush the water heater.

If your house is built on a concrete slab, you obviously don’t have a basement. In that case, you will most likely have a utility room where the water heater, furnace and other appliances will be installed.

That is where you should start looking for your main water shut off valve. Just like is the case with basements, it will be very close to the water heater. Trace the water heater’s cold water pipe and you will surely find the main shut off valve.

If not in the utility room, the main shut off valve could very well be in the garage. In some cases, the valve will also be located inside the cabinet under the kitchen sink.

There will be 2 shut off valves under the kitchen sink (for cold and hot water lines). These valves should not be mistaken with the main shut off valve.

2. Looking for the Main Water Shut off Valve outside the House

If you live in a relatively warmer area, it is not unusual to have the main shut off valve installed outside the house. Again, this valve will mostly be installed alongside the pressure reducing valve.

In most cases, the valve will be installed against a wall, where the main water line emerges from the ground and enters the building. This means that you will locate the valve on the street side of your house.

If you have an external faucet, the main shut off valve will also be located very close to it. This allows both the water flowing to the house and that flowing to the faucet to be controlled by one main valve.

Please note that this only applies to people who use water from the city. If you use water from a private well then the water pipe can enter the house from the rear or even side.

For people who use water from a well, go straight to where the pressure tank is. On the water pipe connecting the pressure tank to the house, you will see a shut off valve.

That is the valve that shuts off water to your house from the well. If there is no shut off valve there, follow the pipe until the point where it enters the house. You will surely see the valve somewhere along that pipe.

3. Looking for the Main Water Shut off Valve Near the Street

If you can’t locate the main water shut off valve inside or outside the house, there is still one more place you can check. The valve may be near the water meter (for water meters located outside the house).

Your water meter will usually be located between your house and the street, near the curb or sidewalk. It is found inside a concrete box with a metal or plastic lid and “Water” or “Water Meter” inscribed at the top.

Use a long screwdriver to remove the water meter lid. Be careful as you are likely to find snakes, spiders or other animals under the lid. Clean the inside of the water meter with a rag.

Once you locate the water meter, know that there is the public side and the private side. The private side is your house’s side of the water meter while the public side is the city’s side of the water meter.

There will always be a shut off valve on the city/public side of the water meter Do not tamper with that valve since it belongs to the city.

Look if there is a second shut off valve on your side of the water meter. If there is, that is the one you need to turn off the flow of water to your house.

4. Looking for the Main Water Shut off Valve in Your Property Inspection Report

You must have been handed a property inspection report when you purchased your house. That can be an effective way of finding exactly where you main water shut off valve is located.

While the property inspection report is a bulky document especially when you want to turn off water to your house during an emergency, it will save you if you can’t physically find that valve in your property.

Head straight to the plumbing section and trace the plumbing pipes from the street to your house. You will surely find the main shut off valve somewhere.

How to Turn off the Main House Shut Off Valve

Once you locate the valve, the first thing you will need to check is the type. Old houses have a gate valve (handle which looks like a wheel) while in modern plumbing you will find a ball valve (operated using a lever-type handle).

If you have a gate valve, grab the wheel with your hand and turn it clockwise all the way. On the other hand if you have a ball valve, move the lever so that it is perpendicular to the water pipe.

Since these valves are rarely operated, they may be corroded and not turn easily. You may therefore need to use more force to persuade them.

Be careful however as use of too much force may break the valve especially in old plumbing. If you can’t turn yours contact a plumber.

You may also notice water dripping from the valve once you turn it off. In that case, use a wrench to tighten the valve’s packing nut and you will notice that the leaking will stop.

Turning off a House’s Isolation Valves

Turning off your main house shut off valve is usually not ideal especially when doing plumbing repairs on isolated fixtures.

Thankfully, most fixtures have a separate shut off valves which you can turn off instead of turning off the main house shut off valve.

For toilets, the shut off valve is located on the wall behind the toilet. The toilet water supply line connects the valve to the tank’s fill valve.

To turn off water to your bathroom or kitchen sink, look for two shut off valves under the sink for both cold and hot water. You may also find other valves for turning off water to the dishwasher or refrigerator under the kitchen sink.

To turn off water to your refrigerator ice maker/dispenser, look for the shut off valve behind it, under the kitchen sink or straight below it in the basement on the cold water supply pipe.

If you would like to turn off hot water supply in your house, look for the hot water shut off valve on your water heater. To turn off water to your water heater, look for the shut off valve on its cold water supply pipe.

It is always a good idea to turn off power to the water heater once you turn off the cold water supply. This prevents the elements from burning when water is drawn from the tank.

The only place it is hard to turn off cold water to is the shower faucet. Some houses have an access panel on the wall behind the shower where there are shut off valves but some do not have. In that case, you will need to turn off the house’s main shut off valve.

Washing machines also have shut off valves on the wall behind them. Just pull the washer forward slightly to access the cold and hot water shut off valves.

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