National Pipeline Mapping System

The National Pipeline Mapping System (NPMS) is a U.S. Department of Transportation (DOT) database managed by the Pipeline and Hazardous Materials Safety Administration (PHMSA) that contains geographic data on natural gas transmission, hazardous liquid pipelines, and Liquefied Natural Gas (LNG) plants, offering public map viewers and detailed access (PIMMA) for emergency response, safety, and planning, but it does not replace the mandatory 811 "Call Before You Dig" service.

What it is

A Geographic Information System (GIS) dataset showing major gas and hazardous liquid pipelines, LNG plants, and breakout tanks.

Maintained by PHMSA in cooperation with federal, state, and industry partners.

Who uses it

General Public: Through the Public Map Viewer (county-by-county basis).

Government Officials & Operators: Via the Pipeline Information Management Mapping Application (PIMMA) for more detailed data.

What it's for

Emergency Response: To quickly locate pipelines during incidents.

Inspections & Compliance: For regulatory oversight.

Planning: For infrastructure protection and smart growth.

Important Note

NPMS data is for reference only. Always call 811 (or your local one-call center) before digging, as the system doesn't show all gathering or distribution lines and has accuracy limitations.