Pipeline Location & Siting Basics
Hazardous liquids and gas pipelines are conduits made from pipes connected end-to-end for fluid or gas transport. See Pipeline Hazardous Materials Safety Administration (PHMSA)’s webpage on Pipeline Construction. However, in legislation, the term “pipeline” has often been used as inclusive of all pipeline infrastructure and related facilities (compressor stations, pipe, valves, breakout tanks, and other appurtenances attached or connected to the pipe). As a result, defining “pipelines,” or pipeline infrastructure, can be confusing.
Pipelines are categorized by what they carry and where they go. They are also defined and categorized by the type of pipe, location, fuel transported, and end point of that fuel. Each category may vary by pipeline size, operating pressure, construction materials, and designation of regulatory authority in terms of siting, construction, specifications, maintenance, inspections, and decommissioning. There are interstate transmission, intrastate transmission, distribution, and gathering pipelines.
Existing Pipeline Locations
Hazardous liquid and gas pipelines of all sizes are typically located underground and may run beneath creeks, rivers, highways, roads, farmland, and parks, and near homes, businesses, schools or other community centers. All pipelines are located in right-of-way (ROW) property easements owned by a pipeline or utility company that run contiguously in order to deliver fuel to specific customers and markets. ROWs can be permanent or temporary acquisitions. (See US Department of Transportation’s ROW Briefing)
Based on 2018 data generated from annual reports to PHMSA from pipeline operators, 2019 data from the Federal Energy Regulatory Commission (FERC), and 2015 date from the U.S. Department of Energy (DOE) Office of Fossil Energy, the national pipeline infrastructure network includes approximately:
- 218,398 miles of Hazardous Liquid or Carbon Dioxide pipelines;
- 301,558 miles of onshore and offshore Gas Transmission pipelines;
- 17,938 miles of Gathering System pipelines;
- 1,307,735 miles of Gas Distribution mains and services pipelines;
- 110 LNG Facilities connected to our gas transmission and distribution systems;
- unknown miles of propane distribution system pipelines (data is held by utilities and is not required to be disclosed to PHMSA); and,
- 126 Underground Natural Gas Storage facilities.

The National Pipeline Mapping System (NPMS) is a geographic information system (GIS) created by the U.S. Department of Transportation, Pipeline and Hazardous Materials Safety Administration (PHMSA), Office of Pipeline Safety (OPS) in cooperation with other federal and state governmental agencies and the pipeline industry.
The NPMS consists of geospatial data, attribute data, public contact information, and metadata pertaining to the interstate and intrastate gas and hazardous liquid transmission pipelines, liquefied natural gas (LNG) facilities, and hazardous liquid breakout tanks jurisdictional to PHMSA. These GIS layers are available to both the public and local governments.
The nominal accuracy of geospatial data in the NPMS is +/-500 feet. To see if a transmission pipeline is located near you, visit National Pipeline Mapping System (NPMS) and search by your County or zip code.
The NPMS should never be used as a substitute for contacting a one-call center before excavating. Remember to call before you dig by dialing 811! 811 is the designated call before you dig phone number that directly connects you to local one call centers. Each state has different rules and regulations governing digging, some stricter than others. The One Call Website (call811.com) will help you find state-specific information and links to submit an online digging request where available.
Most pipeline operators are required to mark underground pipeline paths with colored markers. Markers appear in various shapes, sizes and colors and contain emergency contact information for the company that operates it.
Siting of New Pipelines & Changes to Existing Pipelines
The Federal Energy Regulatory Agency or FERC, is charged by Congress with evaluating whether interstate gas transmission pipeline projects proposed by private companies should be approved. This authority, under Section 7 of the Natural Gas Act, 15 U.S.C. S717f(c), allows FERC to issue a “certificate of public necessity and convenience” for the construction and operation of gas pipelines used to transport gas across state lines. FERC does not have jurisdiction over the siting of intrastate gas pipelines nor inter- and intrastate hazardous liquids pipelines.
In addition to evaluating whether interstate gas pipeline projects proposed by private companies should be approved, FERC approves the location, construction, operation and abandonment of interstate pipelines, facilities, and storage fields involved in moving natural gas across state boundaries. FERC’s determination whether to approve such a project may affect local landowners if their land is where a gas pipeline, other facilities, or underground storage fields might be located. To read more about local landowner topics, public involvement in pipeline siting, and the FERC pipeline determination and siting process please visit Natural Gas Project Landowner/Stakeholder Topics of Interest.
If you are a landowner or tenant and have questions about your property rights related to interstate gas pipeline siting, we also recommend this wonderful guide authored by Pipeline Safety Coalition Board Member, Carolyn Elefant Esq., Knowing and Protecting Your Rights When an Interstate Gas Pipeline Comes to Your Community as well as Pipeline Safety Coalition’s FERC Tips.
Click here for more information on Pipeline Safety Basics, including answers to: What are the different types of pipelines and pipeline infrastructure? Who regulates pipeline safety?
More useful information about hazardous liquids and gas pipeline siting and safety from the PHMSA Website:
Natural Gas Pipeline Systems: From the Wellhead to the Consumer
Petroleum Pipeline Systems: From the Wellhead to the Consumer