Gas Leak 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
  • The leaks are on public streets, not inside buildings.
  • If you are experiencing difficulties viewing the maps, email us.

Gas leak grading indicates how potentially hazardous a leak is, ranging from Grade 1 to Grade 3:

  • Grade 1 leaks are hazardous and must be repaired immediately.
  • 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 leaks have an extent greater than 2000 square feet and 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.

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

You can learn more about HEET’s mapping process here.

We also used this data to help calculate each municipality’s estimated methane emissions from gas leaks.

Due to the LAUF (Lost And Unaccounted For) gas regulations enacted in 2019, utilities are now 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.

Emissions unit: