If you can answer this question — “Where is my main water shut off valve? — then, congratulations! You know the first line of defense in any water damage situation.
You also know the first step in most major plumbing repairs around the home.
This article is for you if you’re uncertain where your main water supply’s shut off valve is located and how to turn it off.
What is the Main Water Shut Off Valve?
The main water shut off valve controls the flow of fresh water into your entire home. Water arrives at your home from a public source of water like your municipality’s water supply. Sometimes, it comes from a private source like a well.
Water first has to get past a gatekeeper to flow through your pipes and find its way to the rest of the house. That gatekeeper is your main water shut off valve. When turned on, the flow of water is available everywhere in your home. When turned off, water is no longer available in your home.
There also are water shut off valves that control the flow of water into a specific fixture (as opposed to the entire house). The shut off valves under your toilet, kitchen sink, or washing machine are three examples.
Where is the Main Water Shut Off Valve?
The main valve for your water supply is usually found in the basement or utility room near the water meter, water heater, or on the front wall closest to the street.
In older apartment buildings, the main water supply valve is located in the basement. However, in some new buildings, main water supply valves are located on each floor in the utility room.
Wait, you don’t have a basement? No problem. Check one of your closets. It’s often found in the closet closest to the front door but could be in any utility closet. If you still can’t find it, look around your water heater (which might also be in a closet).
To make sure you’ve marked the correct valve, turn on a sink faucet and then shut off the main valve. If the water from the sink stops, then you’ve found the right valve.
PRO TIP: To quickly identify the valve in an emergency, hang a bright-colored tag on it.
What Kind of Valve Do You Have?
The two most common main water supply valves are gate and ball.
- Gate Valve: This type of shut off valve has a wheel-shaped know handle (or knob). It is most often found in older homes. It can be difficult to turn if it is dirty or has not been used in a long time.
- Ball Valve: This type of shut off valve is more commonly seen in newer homes. It has a lever handle that requires only a quarter turn to shut it off. If installed properly, the lever is in line with the pipe that it’s attached to when turned on. When turned off, the lever is perpendicular (at a 90-degree right angle) to the pipe.
Shutting Off the Valve
This is the easy part (even easier than finding the main water shut off valve). Here’s how to turn off your main water supply using the main shut off valve:
- Gate Valve: Turn the wheel clockwise.
- Ball Valve: Move the lever a quarter turn (perpendicular to the pipe)
The same instructions above apply for turning off fixture-specific shut off valves.
PRO TIP: We recommend that you test your shut-off valve prior to an emergency, twice a year. This is especially important if you have a less reliable gate valve. We also recommend that if it’s broken, you have someone replace it with a ball valve.
How Do I Loosen a Stuck Shut Off Valve?
To loosen a stuck gate valve, you’ll need lubricating spray like WD-40. Simply apply the lubrication to the nut on the gate valve. After about 20 seconds, you should be able to turn the handle. If it’s still stuck, turn the stem under the handle with an adjustable wrench. Be careful: too much pressure can break the valve.
A stuck ball valve is rare, but it does happen from time to time. To loosen it, apply the lubricating spray and wait about 20 seconds.
It’s hard to think of an easier plumbing task than finding and turning off your main water shut off valve. But in water damage emergencies, we see all the time that it wasn’t shut off, causing thousands of more dollars in damages than necessary.
Now that you can answer “Where is my water shut off valve?”, you no longer have to worry about that happening to you or your home.
1-Tom-Plumber’s certified team of plumbers and drain technicians respond immediately to any emergency plumbing, drain cleaning, or water damage problem. We also handle the excavation of underground water lines and sewer main lines. Our immediate-response team is available every day and night of the year, even on holidays.