How much does it cost to replace a 75-gallon water heater?

Q: How much does it cost to replace a 75-gallon water heater?

Replacing a 75-gallon tank water heater costs $900 to $3,500 installed. Fixr (January 2026) puts it at $1,500 to $3,400 with an average of $2,100; This Old House (June 2026) puts it at $900 to $2,300. At this size the fuel choice splits the price: a 75-gallon electric tank runs $1,000 to $2,000 installed, a gas one $1,300 to $3,500.

The published ranges

Source	75-gallon tank, installed	Date
Fixr, dedicated 75-gallon guide	$1,500 to $3,400, average $2,100	January 2026
Fixr, general size table	$1,100 to $3,400	January 2026
Fixr, gas units only	$1,100 to $3,500	January 2026
This Old House	$900 to $2,300	June 2026

As with the smaller sizes, This Old House sits lower because it prices a basic like-for-like install from Home Depot equipment costs, while Fixr's dedicated guide assumes a standard gas unit with the venting and code work that usually comes with it.

By fuel type, and why it matters more at 75 gallons

Type	Installed cost	Source
Electric	$1,000 to $2,000	Fixr
Gas or propane	$1,300 to $3,500	Fixr
Hybrid heat pump	$2,800 to $5,800	Fixr
Solar	$4,000 to $9,000	Fixr

At 40 gallons, electric and gas start at the same $700. At 75 gallons the gas range runs $300 higher at the bottom and $1,500 higher at the top. A 75-gallon gas tank needs more combustion air and a vent sized for its higher input, and that is where the extra cost sits.

The running costs go the other way, and by more:

Fuel	Per year, 75-gallon tank	Source
Electric	$700 to $1,100	Fixr
Gas	$400 to $600	Fixr
Hybrid heat pump	$200 to $400	Fixr
Solar	$100 to $250	Fixr

Electric costs roughly $300 to $500 more a year to run at this size. Over 10 years that is $3,000 to $5,000, which is more than the entire installed price of either unit. At 75 gallons the standing heat loss of a big tank is doing real damage to an electric bill, and this is the size at which a hybrid heat pump starts to make arithmetic sense rather than just environmental sense. See heat pump water heater cost.

75 or 80 gallons?

Size	Installed, all fuels	Installed, gas	Household
75 gallons	$1,100 to $3,400	$1,100 to $3,500	4 to 6 people
80 gallons	$1,200 to $3,600	$1,300 to $4,000	6+ people

Figures from Fixr, January 2026.

Five gallons of capacity costs $100 to $200 more at the all-fuel level and $200 to $500 more on gas. The practical difference is not the five gallons, it is what each size is built as: 80 gallons is the standard size for electric and heat pump tanks, 75 is more common in gas. If you are staying on gas, 75 is usually the natural size. If you are moving to electric or a heat pump, 80 is where the model choice is.

Where the money goes

Line item	Range	Source
Labor, tank swap	$300 to $1,500	Fixr
Labor, gas tank, 20% to 25% of the total	$200 to $650	Fixr
Plumber hourly rate, 1 to 3 hour job	$40 to $200	This Old House
Old tank removal and disposal	$100 to $300	This Old House
Permit and inspection	$50 to $200	This Old House
Basic gas venting	$300 to $500	This Old House
Direct venting	$500 to $1,000	This Old House
New chimney liner	$500 to $700	This Old House
Expansion tank	$40 to $150	This Old House
Seismic strapping, where required	$100 to $300	This Old House

Weight is a real line item at this size. This Old House prices floor reinforcement for large tanks at $300 to $800. A 75-gallon tank full of water weighs several hundred pounds more than the 40-gallon unit it may be replacing. If you are going up in size rather than replacing like for like, ask whether the floor structure was checked.

How to read a quote for this job

At this size, three things separate a good quote from a cheap one: whether the vent is sized for the new unit's input rating, whether the gas supply line is large enough, and whether anything was done about the floor. A quote that is just "75-gallon gas water heater, installed, $1,800" is not wrong, but it has not told you which of those three it covers.

Sources

Price figures are national US ranges from the sources above as of the date shown. Your local price depends on labor rates, permits and site conditions. Read how we get our numbers.