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Duke Energy Excess Flow Valve (EFV) Program

Excess Flow Valves

Natural gas is a safe and reliable fuel when used properly. However, outside forces (weather, natural disasters, excavation damage) can cause a break in the natural gas service line. An excess flow valve is a device that automatically closes and restricts the flow of natural gas if that flow exceeds prescribed limits, such as when the service line is damaged due to excavation or other similar activities. 

An excess flow valve is designed to permit normal operation of the service line. But, when activated, an excess flow valve may lessen the buildup of natural gas in the service line and may decrease the possibility of accidents caused by such buildup. However, an excess flow valve does not protect against customer appliance malfunction, customer houseline leaks, or small leaks on service lines or gas meters.

Current federal regulation requires Duke Energy to install an excess flow valve on qualifying natural gas service lines for single and multifamily residences and small commercial properties. Where an excess flow valve is not required on service lines installed before the current regulations, customers have the option to install the device at their expense. Operating characteristics and limitations may prevent the installation of an excess flow valve. 

Excess flow valves are designed for use on the gas service line, downstream of the gas main. 
Excess flow valve graphic

EFV Installation Guidelines

Installation of an excess flow valve requires Call Before You Dig notification (811), utility marking, and significant soil excavation on or near customer property where the existing natural gas service line connects to our natural gas main. Natural gas service to the customer’s home or business will be interrupted for a period of time and the customer must be present for natural gas service to be restored upon completion of the excess flow valve installation. The natural gas service line will need to be inspected and all appliances must be operating normally before the customer’s gas service can be restored.

The cost to install an excess flow valve will be the sole responsibility of the customer requesting the installation. The cost to install the excess flow valve varies, depending on the difficulty of the installation, but the average cost of installation is $1,500. Once a customer requests an excess flow valve, Duke Energy will send a representative to the property to confirm that the excess flow valve can be installed and to prepare a cost estimate. The customer will be responsible for the actual cost of installation.

Upon acceptance of the cost estimate and prior to installation, customers will be required to enter into an agreement with Duke Energy. The agreement will contain the terms and conditions of installation including the customer’s obligation to pay for all of the actual EFV installation costs. Installation work will be scheduled at a mutually agreeable date, subject to approval from regulators and permitting authorities, payment arrangements, and weather conditions.

Contact Us

To find out if your property currently has an excess flow valve or to learn more about having one installed at your expense, please call 888.385.3638 or you can email the excess flow valve project team at to get information about the process. You can also find additional details about the project by visiting

Frequently Asked Questions

Excessive Flow Valves