Gas Excess Flow Valves

Natural Gas Excess Flow Valves

All residential and commercial customers within the City of Palo Alto Utilities natural gas service territory can request an Excess Flow Valve (EFV) device be installed on the natural gas pipeline serving their property. 

An EFV is a mechanical device installed on the customer’s natural gas service pipeline that connects the City’s distribution pipeline to the customer’s meter. The EFV acts as a safety device that restricts the flow of gas in the event of a significant pipeline break. Significantly restricting the flow of gas from a damaged pipeline can reduce the risk of personal injury, explosion, natural gas fire and/or property damage. See diagram below, courtesy of Hubbell Incorporated. 

An EFV device will not protect the natural gas service line against leaks caused by corrosion or failed connections on the natural gas service pipeline or meter-set, leaks on customer owned pipelines (houseline) or earthquakes.

Note that if you are upgrading your existing natural gas equipment or adding natural gas equipment that require an increase in natural gas supply (e.g., a pool heater, emergency generator etc.), the additional gas flow may cause the EFV to close. In such cases, your natural gas service and EFV will need to be reviewed to avoid falsely activating the EFV.

If the City determines an EFV can be installed on your natural gas pipeline, you will be billed all applicable costs for the installation. Please contact (650) 566-4501 to speak with someone about the requirements of having an EFV installed.

For your safety, please always call 811 to have gas lines and other buried utilities marked before allowing anyone to dig on your property.