Gas Leak Maps

The Maps

Every year, Massachusetts gas distribution utilities are required to report the location of gas leaks and leaks that were repaired in their territories to the Department of Public Utilities. HEET uses the reports to create the maps and information below. Use these maps to zoom in on your home, school, or business to find local gas leaks. Remember:

• The maps are snapshots in time as of the last day covered by the report, December 31 of each year
• Any one leak could have been repaired since or new ones developed
• Independent researchers typically find 1.5 to 3 times as many leaks as utilities report
• Google Maps places map pins on buildings – the leaks are on public streets, not inside buildings
• You can learn more about HEET’s mapping process here

Leak Grades

Gas leak grading indicates how potentially hazardous a leak is, ranging from Grade 1 to Grade 3. Leak grades are now indicated on the maps as numbers in the leak map pins, for example,is a Grade 3 unrepaired leak. Grades are defined as follows:

• Grade 1 leaks are hazardous and must be repaired immediately. This includes leaks in or near a contained space, such as a building or manhole, where the gas could build up enough to potentially explode.
• Grade 2 leaks are non-hazardous, but could be hazardous in the near future. They must be repaired within a year.
• Grade 3 leaks are non-hazardous and are expected to remain non-hazardous. Grade 3 leaks initially designated on or after 1/1/2018 are required to be repaired or eliminated within 8 years. 
• Grade 3 SEI are grade 3 leaks larger than 2000 square feet in rectangular extent – these are leaks of significant environmental impact, or SEI’s. They are approximately the largest 7% yet contribute approximately 50% of all leak emissions. They are required to be repaired in 1-3 years. HEET is working to improve utility adoption of the leak extent method to better identify SEIs in the field.

Emissions Estimates

Estimated methane emissions from gas leaks are now calculated and included in the tables below.

Due to the LAUF (Lost And Unaccounted For) gas regulations enacted in 2019, utilities were required to submit standardized estimates of their annual statewide methane emissions from leaks to the DPU. We used the same data and methods from utilities’ estimations, but with municipality-specific data (from the geocoded leaks dataset) substituted for statewide data where applicable.

These are underestimates due to only including reported leaks, and that the state is using an older conservative method of estimating the rates at which methane emits from leaking pipes. More information on the LAUF data and emissions estimates can be found on the LAUF Calculator page.

Data Sharing

We share our geocoded leaks data under a Creative Commons license. Please contact us directly if you would like a copy.

Leak Maps by Utility

Click on a utility to open its map.

Leak Maps by Town

Click on a town to open its map.