Based on recent enjoyment of the Big Dig podcast

https://www.wgbh.org/podcasts/the-big-dig

Boston’s streets are an unholy Tetris of water, gas, electricity, transportation tunnels, ratty raceways, internet fiber and graft.

It’s entirely possible that the contractors have no information about the placement of any or all of this infrastructure, which turns a gas supply line replacement into a scavenger hunt.

None of which makes this any more pleasant for you!