Knowing how to shut off the main water supply to a home is a necessary skill for any property owner. This action is often required during plumbing repairs, such as replacing a faucet or toilet, to ensure a dry workspace. More importantly, quickly closing the main valve can significantly limit property damage during an emergency like a burst pipe or a major leak. Locating and operating this valve provides immediate control over the entire water system entering the structure.
Locating the Main Shutoff Valve
The primary outdoor shutoff point is typically found within a concrete or plastic box near the street or property line, often housing the water meter itself. This meter box contains the connection where the municipal water line transitions to the homeowner’s service line. Inside, there are usually two valves: one on the utility side and one on the house side. The house-side valve is the one the homeowner is permitted to operate for routine shutoff.
A second potential shutoff point is the curb stop, a valve buried underground near the curb or sidewalk. This valve is usually the property of the water utility and is intended for use by their personnel to isolate the service line. While it can be operated in an extreme emergency, tampering with the utility’s connection can sometimes lead to fines or liability. It is best practice to first attempt to use the house-side valve located immediately after the meter.
Necessary Tools and Safety Precautions
Necessary Tools
Accessing the outdoor valve requires a few specific tools. A specialized water meter key, a long, T-shaped wrench, is the most effective tool for reaching and turning valves deep within the meter box or curb stop. For valves with a standard handle or nut, an adjustable wrench may also be useful for providing leverage.
Safety Precautions
Before opening the meter box, put on heavy-duty gloves, as the box may contain sharp edges, dirt, or small animals. The lid can be heavy and should be lifted carefully to avoid injury. Once the lid is removed, clear away any dirt or debris obscuring the valve mechanism to ensure a clean connection for the wrench.
Step-by-Step Guide to Closing the Valve
Once the house-side valve is located, the method for closing it depends on the type of valve installed. The two most common types are the ball valve and the gate valve, each requiring a different turning action.
Ball Valve
A ball valve is easily identified by its lever handle, which is aligned parallel to the pipe when water is flowing. To shut off the water, the handle must be turned 90 degrees, or a quarter-turn, until it is perpendicular to the pipe.
Gate Valve
The gate valve, typically found in older installations, features a round, multi-turn handle that operates a wedge-shaped gate inside the pipe. To close this valve, the handle must be turned clockwise multiple times until the gate is fully lowered and firm resistance is felt. Avoid over-tightening the gate valve, as this can damage internal components and cause the valve to leak or fail to open again.
Curb Stop Valve
If the valve is a curb stop style, the T-handle meter key is inserted down the access pipe to engage the operating nut. This nut is then turned clockwise until the water flow stops.
Post-Shutoff Procedures and Troubleshooting
Relieving Pressure
After the main valve is closed, relieve the remaining pressure within the home’s plumbing system. This is accomplished by opening a faucet at the lowest point in the house, such as an outdoor spigot or a basement sink. Allowing the water to drain prevents air pockets and reduces the chance of pressure surges when the water is turned back on.
Troubleshooting Stuck Valves
If the valve is difficult to turn or appears stuck, forcing it should be avoided, as this can cause the valve stem to break or the pipe to rupture. Older gate valves are susceptible to becoming stuck due to mineral deposits and corrosion. If the valve cannot be closed completely or begins to leak, the local water utility or a licensed plumber should be contacted immediately. They possess the specialized tools and authority to safely address issues with the main service line connection.