The National Pipeline Mapping System (NPMS) Public Viewer enables the user to view NPMS pipeline, liquefied natural gas (LNG) plant and breakout tank data one county or offshore area at a time, including attributes and pipeline operator contact information. The user can also view gas transmission and hazardous liquid pipeline accidents and incidents going back to 2002 for the entire US. NPMS pipeline data consists of gas transmission pipelines and hazardous liquid pipelines jurisdictional to PHMSA. It does not contain gas gathering or distribution pipelines, such as lines which deliver gas to a customer 's home. Therefore, not all pipelines in an area will be visible in the Public Viewer. As well, the breakout tank data is not complete as submission of that data is not a requirement. All NPMS data is for reference purposes only. It should never be used as a substitute for contacting a one-call center prior to excavation activities. Please call 811 before any digging occurs.

To view the data, select a state or the federal waters category and then a county or offshore area from the drop-down lists below. To view another county or offshore area, click the Change County link at the top right corner of the map window. Please note that the Public Viewer limits the scale of pipeline maps, in accordance with PHMSA's security policy. When you are zoomed in closer than a 1:24,000 scale (above zoom level 14), you will notice that the pipelines have disappeared from the map. In order to see the pipelines, you must either zoom out to zoom level 14 or lower. Data cannot be downloaded from the Public Viewer. The boundary between counties and offshore state waters is for display purposes only and is not an official boundary.