How much does it cost to replace a gas water heater?

Prices checked October 2026. Wages: BLS, May 2025.

Most gas water heater replacements are a straight swap, and that is what the range above prices: a new gas tank of the size you pick, set in the same spot, connected to the gas, water and vent you already have. Two numbers go in. One is what the heater sells for at public online retailers. The other is the average installation cost from the Department of Energy's 2024 water heater analysis, which counts labor, fittings, delivery, hauling off the old tank and a typical permit fee. That labor portion is then scaled up or down by what plumbers earn where you live.

Sizes offered are 40, 50 and 75 gallon standard-vent tanks, plus 40 and 50 gallon power-vent models. Some code and venting items only apply to certain homes, such as a thermal expansion tank, a drain pan, a new vent connector or a chimney liner. Those sit below the main figure as separate lines, since folding them into every estimate would overstate the cost for most people. When a quote lands well above the range, look there first.

Installed price by size, national

Size	Unit (list)	Low	Typical	High
40 gallon, standard vent	$993	$1,650	$1,900	$2,400
50 gallon, standard vent	$1,080	$1,700	$2,000	$2,550
75 gallon, standard vent	$1,858	$2,450	$2,800	$3,300
40 gallon, power vent	$1,813	$2,450	$2,750	$3,150
50 gallon, power vent	$1,911	$2,650	$2,850	$3,400

Installation averages $905 nationally for the common size (DOE, inflated to August 2026); about 53% of that is labor, which we scale to local wages.

Extras that may be added

Item	Typical	Range
Thermal expansion tank (where code requires it)	$200	$150–$360
Drain pan with drain line	$50	$36–$85
New vent connector	$375	$300–$488
Flue or chimney liner update	$1,133	$906–$1,473

What moves the price

Standard vent or power vent

A standard (atmospheric) tank sends exhaust up a metal flue by natural draft, usually into a chimney or a vent shared with the furnace. A power-vent tank has a blower on top that pushes exhaust sideways through plastic pipe, so it can sit in a basement with no chimney. The blower needs an outlet nearby, and the unit itself costs noticeably more. Plan on replacing a power vent with another power vent. Switching a power-vent home back to natural draft usually is not possible.

Tank size

Moving from 40 to 50 gallons changes the equipment price more than the labor, since DOE's installation figure is nearly the same for both. A 75 gallon tank is heavier, often needs a larger vent, and can trigger a bigger gas line. Size by household use. A family running two showers back to back is the usual case for 50 gallons.

Local plumber wages

About half of DOE's average installation cost is labor. That share is multiplied by your area's plumber wage relative to the national median from the federal wage survey. In a high-wage metro the labor portion can run well above the national figure. The tank price barely moves from place to place.

Venting and chimney condition

DOE's furnace analysis found that roughly a quarter of replacements need a new vent connector and a smaller share need the flue or chimney updated. A water heater left alone in an oversized masonry chimney after the furnace moves to plastic venting (an orphaned water heater) is the classic case. Those costs are shown as separate lines so you can see whether a quote includes them.

Code items your city enforces

A.O. Smith's installation guide says plumbing codes require a thermal expansion tank in almost all homes, and that most codes require a drain pan piped to a drain. California law requires every water heater to be braced, anchored or strapped against earthquakes. When the old install skipped any of these, the replacement is when an inspector will ask for them.

Repair or replace?

Repair makes sense on a tank under about ten years old with a failed part outside the water: a thermocouple or flame sensor, a gas control valve, a relief valve or a drain valve. Those are bounded jobs, and the tank keeps working. Replace when the tank itself leaks, when rusty water comes from the hot side only, or when the heater is near or past DOE's average life of about 14.5 years and needs anything bigger than a small part. Nobody patches a leaking tank. Also weigh a control valve repair against the full replacement figure above. On an older heater, the valve plus labor can reach a large fraction of a new installed tank, and the rest of the heater is still old.

Run the numbers for your unit.

What a complete quote lists

Exact model number, capacity in gallons and vent type (standard or power vent)
Removal and disposal of the old tank
Gas connection: new flex connector, shutoff valve and sediment trap
Water connections, new supply lines and a new temperature and pressure relief valve with a discharge pipe
Vent work: reusing the existing connector, or replacing it (with the reason)
Thermal expansion tank, if your system is closed by a check valve or pressure regulator
Drain pan and drain line where a leak would cause damage
Seismic straps if you are in California or another area that requires them
Permit and inspection fee, named as a line
Manufacturer tank warranty length and the installer's labor warranty

Paste your quote and we'll tick these off for you.

Gas tank water heater prices by metro

Common questions

Why is my quote higher than the range shown?

Check what it includes beyond the swap. A new vent connector, a chimney liner, an expansion tank, a drain pan, gas line changes or moving the heater to a new spot all add cost and are shown separately above. A larger tank or a power-vent model also raises the equipment price.

Does the estimate include the permit?

DOE's installation average includes applicable permit fees across its sample of homes, so a typical permit is built in. Fees differ a lot by city. If your city charges more than average, or the quote lists the permit as a separate line, that is normal.

Do I need an expansion tank with my new water heater?

Often yes. When a backflow preventer, check valve or pressure reducing valve keeps heated water from flowing back to the street, the system is closed and the water has nowhere to expand. Plumbing codes then require thermal expansion control on the cold supply. Your plumber or city inspector will know the local rule.

How long should a new gas water heater last?

DOE's 2024 analysis uses an average of about 14.5 years for gas tank heaters, with a range of roughly 12.5 to 16.5 years. Hard water, high temperature settings and a spent anode rod shorten that.

Can I switch to a tankless or heat pump unit instead?

You can, but it is a different job with different costs. See the tankless and heat pump water heater pages for what those installs involve, such as gas line sizing, new venting, a condensate drain or a 240 volt circuit.

Is a power-vent model worth the extra cost?

Only if your home needs it. Power venting solves a missing or unusable chimney. If your existing standard vent works and passes inspection, a standard-vent tank is the lower-cost choice.