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Do you know what an EFV is?

Post Date:03/04/2019 8:24 AM

As part of our commitment to providing you with safe, reliable energy, the City of Mesa strives at meeting or exceeding all federal and state requirements for safe pipeline operations and maintenance. 

An Excess Flow Valve (EFV) may be installed on your gas line.  The City of Mesa has installed EFVs on most new or replaced residential gas services since January 2008. Beginning in April 2017, the program was expanded to include installation on multi-family residences and single, small commercial services not exceeding 1,000 SCFH (Standard Cubic Feet per Hour).

What is an EFV?  An EFV is a mechanical safety device installed on the City's gas service line and is designed to automatically restrict the flow of natural gas if the pipe breaks or is severely damaged, most often associated with excavation or vehicle impact with the meter assembly. EFVs are installed either at the service line connection to the gas main or at the customer’s property line.

How will an EFV affect my gas service? Your EFV is designed to automatically restrict the flow of gas if the service line receives significant damage between the EFV and the meter assembly. A small puncture of the service line typically won't trip the EFV; nor does it protect against appliance malfunction or customer household leaks.

It is important to note that an EFV does not shut off the flow of gas completely. A very small amount of gas may bleed-by as the EFV tries to automatically equalize pressure across the EFV. There will not be any blowing gas to identify that a line has been damaged, but there will typically be enough gas to indicate a gas odor. Because an EFV restricts the flow of gas, it reduces the potential for explosions, fires, and personal injury. To report a damaged service line or if you smell gas in or outside of your home call 480-644-4277 (GASS).

For more information on EFVs visit our website at, or watch this quick video about EFVs.


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