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How long do water heaters last?

Gas tank water heaters typically last 8–12 years, electric tank water heaters 10–14 and tankless water heaters 15–20. Where yours falls in that range depends on how hard it works, how it's been looked after, and (for tank water heaters) your water. The best predictor is its age, which is coded in the serial number.

TypeTypical lifeReplacement cost (installed)
Gas tank water heater8–12 years$800–$2,500
Electric tank water heater10–14 years$600–$2,200
Tankless water heater15–20 years$1,400–$5,600

How old is yours?

Enter the serial number from the data plate. We'll decode the manufacture date and tell you how much typical life is left, adjusted for your state.

Brand guides: Bradford White · A. O. Smith · State · American Water Heater · Rheem · Ruud · Whirlpool · Navien · Rinnai· Where to find the serial number

Where your water heater is in its life

TypeEarly lifeMid-lifeNearing the endPast typical life
Gas tank water heaterunder 4 yrs4–6 yrs6–12 yrsover 12 yrs
Electric tank water heaterunder 5 yrs5–8 yrs8–14 yrsover 14 yrs
Tankless water heaterunder 8 yrs8–12 yrs12–20 yrsover 20 yrs

Stage cut-offs are our own rule of thumb (half and 80% of the low end of the typical range), used to decide when a repair stops being worth it.

What wears water heaters out faster

These are estimates. The direction is supported by the sources below, but nobody has measured the size of the effect, so treat them as a rough guide. Our decoder applies them automatically when you pick your state.

Repair or replace?

We compare the repair bill with the cost of a new unit, and get stricter as the unit ages:

StageRepairRepair, but plan to replaceReplace
Early lifeAny repair (check the warranty first)——
Mid-lifeunder 30% of replacement30–50%over 50%
Nearing the endunder 15%15–30%over 30%
Past typical life—under 15%over 15%

Example: a new gas tank water heater costs about $1,650 installed (midpoint of $800–$2,500). Once it's 6+ years old, a repair over about $495 points to replacing.

The 30% and 50% marks are widely used contractor rules; the stricter bands for older units are our own. If a new, more efficient unit would pay for itself in energy savings within half its life, we lean toward replacing. A leaking tank means replacing regardless: the tank itself can’t be repaired.

Typical repair costs

RepairTypical cost
Thermocouple / pilot assembly (gas)$100–$325
Thermostat replacement$100–$350
Heating element (electric tank)$100–$350
Anode rod replacement$150–$350
Gas control valve$150–$550
Tankless flush and descale$150–$350
Tankless heat exchanger$600–$1,300

Published 2026 ranges from national cost guides. Prices vary a lot by region and contractor; get a quote.

FAQ

How long does a gas tank water heater last?

Typically 8–12 years, based on industry life-expectancy studies (NAHB and InterNACHI, plus DOE for tank vs tankless). Your unit's real life depends on how much it runs, maintenance and, for tank water heaters, how hard your water is.

How long does an electric tank water heater last?

Typically 10–14 years, based on industry life-expectancy studies (NAHB and InterNACHI, plus DOE for tank vs tankless). Your unit's real life depends on how much it runs, maintenance and, for tank water heaters, how hard your water is.

How long does a tankless water heater last?

Typically 15–20 years, based on industry life-expectancy studies (NAHB and InterNACHI, plus DOE for tank vs tankless). Your unit's real life depends on how much it runs, maintenance and, for tank water heaters, how hard your water is.

How do I find out how old my water heater is?

The manufacture date is coded into the serial number on the unit's data plate. Each brand writes it differently. Enter the serial in our decoder to get the date, the age, and how much typical life is left.

Is it worth repairing an old gas tank water heater?

Compare the repair with the cost of replacing. Near the end of its typical life (about 6+ years), a repair over about 30% of replacement cost usually isn't worth it. A new gas tank water heater typically costs $800–$2,500 installed, so that's roughly $495.

More guides: How long do furnaces last? · How long do AC units last?

Sources