What people are quoted here
Nobody publishes one price, so here are dated ones.
Two Massachusetts plumbers who post their prices put a standard 40 or 50 gallon tank, installed, at $1,800 to $3,500 (August 2026) and $2,500 to $5,500 (March 2026). A Boston-area installer lists a chimney-vented gas tank at $2,400 to $2,900 for 40 gallons and $2,700 to $3,400 for 50, and an electric tank at $1,900 to $3,200.
National guides run lower. Angi's July 2026 average is $1,348. Massachusetts quotes run higher than the national figures, and a quote here that matches the national number should make you ask what was left out.
So for a like-for-like tank in an ordinary basement, the low to mid thousands is the range these dated quotes support. A number far above it deserves a second call.
What moves a quote up
How the heater vents is the biggest one. A gas tank that vents up a chimney is the cheaper job. One that vents through the wall with a fan costs more for the unit and for the installation.
Where it sits is the next. A heater on an upper floor, or anywhere above finished space, needs a drain pan under Massachusetts code. More on that rule.
Massachusetts also requires a vacuum relief valve on the cold line above every tank heater. It is a small brass fitting, and it belongs in the price.
An expansion tank is required here only where the water meter has a check valve or backflow preventer, which makes the house a closed system. In other houses it is optional. Ask which yours is before paying for one.
Nights and weekends cost more. This Old House puts the after-hours premium at $200 to $500.
Three things the quote should state
The price, as a flat number for the whole job. Hourly billing on a replacement leaves the total open.
Hauling away the old tank. National guides put that at $100 to $500 when it is billed separately.
The warranty on the tank and on the labor. Tanks are sold with 6, 9 or 12 year warranties, and the tier is part of what you are paying for. What a tank warranty covers.
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The license
Only a master or journeyman plumber licensed by the state board can replace a water heater in Massachusetts. There is no homeowner exception, and a handyman or general contractor cannot do the job.
The same license covers the gas line. The state board says any licensed master or journeyman plumber may do the work of a gas fitter. It does not run the other way: a licensed gas fitter may not do a plumber's work. Propane is its own category, with separate installer licenses, so if the heater runs on propane ask who is doing the gas connection.
Ask for the license number on the phone. You can check it on the state's license lookup, or call the Board of State Examiners of Plumbers and Gas Fitters at 617-727-9952.
Tank, tankless or heat pump
A tankless heater lasts longer than a tank and uses less gas. It costs more to put in, because it needs a vent through an outside wall, outside air, more gas and an outlet. What it saves and what it needs.
The three kinds of heater, the rebates and what ended in 2025 are set out here.