How to Repair a Damaged Main Shutoff Valve

Steps:

1. Replacing the main shutoff valve is a risky job that should be left to professionals only.
2. If the homeowner-accessible shutoff is not holding, the water utility usually has access to another shutoff in the street.
3. When working in a multifamily home or if the main shutoff is damaged, water can be held back temporarily by freezing the pipe. Freeze the pipe just before the main shutoff valve. Let the pipe-freezing tool work for a little while to ensure all the water in that section of pipe is frozen.
4. Cut out the damaged main shutoff with the pipe cutter and solder on the new connection as quickly as possible. Upgrade older gate valves to a more reliable ball valve.
5. Turn off the pipe-freezing tool and let the pipe unfreeze.

Pro Tip: Richard Trethewey cautions homeowners to be careful when operating an older main shutoff: “Don’t jerk it… you don’t want to force it because there’s nothing between us and the full city water pressure.” If the valve won’t budge, call a licensed plumber rather than risk breaking it and causing a flood.

Resources:

If the house’s water main shutoff malfunctions, the water utility usually has a shutoff outside the home that they can access.

Richard showed two methods of freezing a pipe when working in a multifamily home or where no outdoor shutoff is available. One uses carbon dioxide; the other is a refrigerant-based machine. Pipe freezers can be found at plumbing supply stores or rented from tool rental shops.

Richard recommends upgrading older gate valves to the more reliable ball valve, which can be found at plumbing supply stores and home centers.

Expert assistance for this segment was provided by A.E. Carter Plumbing and Heating.

How a Ball Valve Works: Richard demonstrated the inner workings of a ball valve using a cutaway model. Inside the valve body sits a stainless steel ball — hence the name — that rests against a seat. When the valve is closed, no water passes through. When the handle is turned to the open position, a full port allows water to flow freely while the seal remains intact. The single handle aligns with the direction of flow, so you can tell at a glance whether the valve is open or closed.