How Pipelines Work

The Washington Gas system is part of a vast nationwide network of mostly underground pipelines that deliver natural gas. We operate a relatively small segment of Department of Transportation (DOT)-regulated transmission pipelines – approximately 180 miles – and thousands of miles of distribution pipelines.

Typically, transmission pipelines carry natural gas at higher pressures from “gate stations,” where gas enters the pipeline system, to “regulator stations,” where pressure is reduced for distribution to customers. Pipeline markers indicate the presence (but not the exact location or depth) of transmission pipelines in underground rights-of-way. Pipeline markers identify the type of fuel being transported and the name of the pipeline operator and the 24-hour, toll-free phone numbers to call in the event of an emergency. Nearly one-half of Washington Gas’ transmission pipelines are in High Consequence Areas (HCAs) where the potential failure of a pipeline could have significant impact on people or property.

Distribution pipelines deliver natural gas directly to customers and, like transmission pipelines, can have an impact on people and property if damaged by digging or excavating. The majority of underground distribution pipelines are generally not marked above ground, so it is critical to call 811 to have the lines located before you begin any digging, gardening or excavating. This service is free.

For additional information, contact our Damage Prevention Hotline at 800-428-5364 with your questions and contact information. A Washington Gas representative will return your call.

Additional Resources:

National Pipeline Mapping System:


Gas Pipe Maintenance - Washington Gas Responsibilities

Washington Gas owns and maintains all natural gas pipes up to and including the gas meter. Our primary focus is to provide safe, reliable service while ensuring that the gas pipe owned by the company is properly maintained. These efforts help avoid the potentially damaging effects of leaks and corrosion on natural gas pipes.


Gas Pipe Maintenance - Customer Responsibilities

Each customer is responsible for maintaining and monitoring all aboveground and underground piping on the customer’s side of the meter. If this piping is not properly maintained, it may corrode or leak. Gas piping located on your side of the meter should periodically be inspected for leaks and corrosion, and if necessary, repaired by a licensed natural gas contractor if any unsafe conditions are detected.

Additionally, it is very important to keep the area around your gas meter clear of all objects, including mulch, construction debris or other flammable materials that could create a fire hazard.

If at any time you smell natural gas, immediately evacuate the premises and then call 911 and 844-WASHGAS (927-4427) (select option 1) from a safe location.


Access to Washington Gas-Owned Equipment

At Washington Gas, safely and reliably meeting the energy needs of our service area is our highest priority. 

Our distribution network is routinely subject to maintenance and oversight both within the company and at the federal and state levels. The customer must provide access to the company-owned gas meter and piping at all reasonable hours for routine surveys and maintenance, and at all times for emergency purposes. If Washington Gas or one of its contractors attempts to complete work at your property and cannot gain access to the company-owned meter, gas pipes or other natural gas equipment, you may receive a notice on your door.

To ensure continuing gas service, please use the contact information provided on the notice to arrange for access as soon as possible. 

For more information about the provisions for access to company-owned equipment and the maintenance and monitoring of all pipelines on your property, please refer to the tariffs for your state:


Enclosed Structures

Please be advised that building a structure over – or too close to – a natural gas pipeline is a safety hazard and an unacceptable building practice that may be in violation of federal and/or local pipeline safety regulations.

Washington Gas policy prohibits building an enclosed structure over a natural gas line. If you have an enclosed structure over your gas line, or believe you do, please contact us at 703-750-4360 to arrange for a locating inspection.


Excess Flow Valves

An excess flow valve (EFV) may reduce the consequences of a gas leak in the event of a break in the outside service line. The valve is designed to shut down the gas service to your home and reduce the likelihood of unrestricted gas flow from the broken line. Since January 1999, in response to government regulation, Washington Gas has been installing EFVs at no additional charge to customers on all new residential natural gas service lines and in cases where residential service lines must be replaced. We will install an EFV on an existing natural gas service line for a cost to the customer of approximately $2,000 - $3,000, depending on the time and labor necessary for the installation. 

For more information about EFVs, or if you want an EFV installed on your existing residential service line, call our Customer Service department at 844-WASHGAS (927-4427).

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Customer Service 844-WASHGAS