How to Use a Water Main Curb Valve Curb Stop
April 30, 2019
What is a water main curb valve or curb stop valve?

This is the valve that is typically located 3-4′ below the sidewalk and is usually within 2′ of the curb line before the roadway. This valve should have a curb box or curb sleeve installed directly on top of the valve which serves as the access point in case of an emergency.

Curb box installed over new valve
Curb box installed over new valve

New curb box cemented in place
New curb box cemented in place

To access the curb valve you would remove the cover  and use a  tool known as a curb key which can open and close the valve as needed.

Using curb key to close curb valve
How to use a curb valve

First you must remove the cover which can easily be removed by hand. In some cases you may need to use a tool with a flat edge to remove the cover if it has been set or rusted in place for an extended period of time.

Once the curb box cover has been removed you should insert the curb key into the sleeve and make sure the square end of the key sits snug on top of the curb valve nut (AKA operating nut).

Curb valve operating nut

Curb key square
Curb key square
Why is a curb valve installed?

A curb valve is installed in the event that the main water supply from the city water main must be closed. The curb valve would most commonly be utilized if you have a leak on the property or if your internal plumber is working inside the house and the main control valve is no longer working.

How is a curb valve installed?

A curb valve is installed by joining two sections of pipe on each end of the curb valve. The connection type is dependent on the material of the pipe that was used for the installation. For example if you have a copper pipe you would use flared fittings and if using ductile iron pipe  you would use mechanical joints for the connection.

Flared fittings

Curb valve below ground
Mechanical joint
A few key points to be mindful of when utilizing a curb valve
  1. Turn the valve clockwise if you are looking to close the valve (stop the water from the street).
  2. Make sure that the curb key fits on the operating nut of the valve. If you force the key on the valve there is a possibility of damaging the valve.
  3. If water is leaking through your curb valve, closing the valve is not guaranteed to resolve the issue. If the leak is on the street side of the valve you are required to open the street to stop the water.
  4. Make sure you insert the cover of your curb valve flush with the surrounding concrete to avoid a potential trip hazard.
  5. If your water main is old and outdated we strongly suggest not to touch the curb valve. This will lead to greater and more expensive problems. Please take a second to understand the true risk of attempting to utilize an old water main curb valve. 
What to do if your curb valve is not working?

The first step is to understand why the valve is not working. Is it a user issue and you do not have the correct tool to open or close the valve? Is the valve not spinning and stuck in the open or closed position? Are you experiencing too heavy of a leak at the valve and cannot get on top of the curb valve operating nut?

There are many other variables which may occur in addition to the few noted above, it is important to speak with a licensed plumber on the next step to resolve any open curb valve related issues.