As of December 2018, National Grid reported 175 unrepaired gas leaks in Weston. This was a 24% increase from December 2017, the result of aging pipes and limited non-emergency maintenance. The oldest of these gas leaks was first reported over 20 years ago.

In February 2019, the Town of Weston approved a SWAG proposal to carry out an independent Gas Infrastructure Audit to confirm leak locations and assess their size and impact.

The Audit identified 292 unrepaired gas leaks in Weston – 67% more than reported by National Grid. Of these leaks, 35% are classified as large volume. Using the industry standard “leak extent” method, 102 of the leaks measured 2,000 ft2 or more. These large volume leaks are deemed of “Significant Environmental Impact” (G3SEI) according to the latest ruling by the Department of Public Utilities. The largest leak was first recorded by National Grid in April 1999 and measures 14,400 ft2 – larger than 5 tennis courts.

The Audit also assessed over 320 trees as either already compromised or at risk due to their location in the gas leak zone. The cost of removing and replacing one tree alone, can be as high as $2,000-3,000.