Licensing is strict here
Across the Commonwealth, two separate licenses come into play: a plumber's license for the water side and a gas fitter's license for connecting the gas, both issued by the state examiners board. Local inspectional services or building departments issue separate plumbing and gas permits. State law also requires carbon monoxide alarms in homes with fossil-fuel appliances.
Water, winters and heat pumps
Boston and the MWRA communities drink very soft reservoir water, while Worcester and Springfield also rely on soft surface supplies; towns on wells may have harder water or iron. Soft water means little sediment but faster anode wear. Winter inlet water near 40°F makes undersized tanks run short. The Mass Save program has offered generous rebates on heat pump water heaters, which suit the state's damp basements well.
Typical repairs run $175 to $650, and a gas tank replacement usually costs $2,000 to $4,000 including permits. See water heater replacement for details. Each city below has its own page.