Natural gas is a safe, clean, and efficient energy source, and KUB’s rigorous safety measures (see box) and tools like excess flow valves help keep our customers safe. You don’t need an excess flow valve for the safe operation of your gas service line under normal conditions, but it is an additional safety option designed to activate if your service line is severed.

What Are Excess Flow Valves?

Excess flow valves (EFVs) are safety devices installed on buried gas service lines at the connection to the main (see diagram). They remain open under normal gas flow but activate if there is a surge, which can occur if the line is severed by, for example, excavation or a natural disaster like an earthquake. If there is a surge, the ball (or plunger) and spring system in the EFV closes to allow only a small amount of gas into the service line.

Most severed lines occur when you or an excavator dig on your property and hit your service line. See Call Before You Dig! to learn to dig safely.

Important notes:

• Homes with service lines installed in or after 1999 probably already have EFVs.
• EFVs activate only if your service line is severed.
• EFVs do not activate if your service line is only punctured or has a small leak—or if there is a leak on your fuel line or appliances.
• EFVs do not prevent leaks. For your safety, know how to recognize and react to a potential leak and follow our recommended safety precautions. 
• EFVs do not operate on all gas service lines.
• EFVs are inexpensive to install when a service line is first installed or later replaced. [KUB passes that cost to the customer.] They are more expensive to retrofit or replace if the valve fails or a customer installs equipment that requires more gas than the EFV will allow through the service line.

When Does KUB Install Excess Flow Valves?

KUB installs EFVs on new, renewed, and replaced service lines for single- and multi-family residences and small commercial businesses. [The cost is included in what the customer pays for the new service or replacement.]

If your home’s service line was installed in 1999 or later, you probably already have an EFV. Or KUB can add an EFV to an older line for a minimum cost of $500 per natural gas service line. The cost will vary depending on the location of your service line. Please note that the installation, which will be scheduled for a mutually agreeable date, will result in a service interruption.

For more information or to request an EFV, e-mail efv.request@kub.org or call KUB New Service at 865-558-2555.