What Every Homeowner Needs to Know About Water Shutoff Valves

The water shutoff valves in your home are your lifeline in the event of a plumbing emergency. A broken water line or fixture can pump gallons of water into your home, between the walls, or into your yard in a short period of time. Not only will this leave you with a huge water bill on top of the line repair, but it can also lead to major damage to your home.

Types of Shutoff Valves

There are two main types of shutoff valves on the average home's water system.

Main Valve

The main valve controls all the water coming in from the municipal water supply. Every other water line running throughout your home comes off of this main valve as it is the primary point of entry. This is the valve that must be shut off in the event of a leak in your main water line or if you are unsure of where the leak originates. The main valve is typically located in the basement, garage, a utility room, or in a utility box just outside the house.

Secondary Valves

Secondary valves are those that control the water into a specific room for a fixture. There are secondary valves by the hot water heater, behind each toilet in most homes, as well underneath the sinks. Appliances like fridges, washing machines, and dishwashers may also have their own secondary valves.  A secondary valve may control one or more taps and appliances. Often there are two secondary valves — one for hot and one for cold water. If you aren't sure what a valve controls, turn it off and test all of the water using fixtures in the room to check.

Shut Off Protocols

Knowing where the valves are located is only half of what you need. You also must make sure you can actually operate them in the event of an emergency.


All shutoff valves should be tested regularly. Twice a year, perhaps at the same time you test smoke detectors, is a good goal. Without use, valves can become stuck or hard to operate. If a valve won't move easily, then a few drops of lubrication may be necessary. In the event the valve is completely stuck, then repair or replacement may be needed.

Emergency Tactics

If an emergency arises and the valve is stuck, you may be able to open it by adding a bit of a lubricant. Tap it lightly with a hammer to help move it toward the closed position. Repeat the process with oil and tapping until you can move the valve freely.

Contact a plumber if you need more assistance.