How long does a water heater last?

Published July 21, 2026.

A conventional storage-tank water heater typically lasts about 8 to 12 years, while a tankless unit can run 15 to 20 or more. Energy Star puts tankless life expectancy at 20 years, longer than any tank-type heater. Your actual number depends on water hardness, how hard the unit works, and whether it gets basic yearly maintenance. If yours is past 10 and showing rust, noise, or leaks, it is time to plan a replacement rather than wait for a cold-shower emergency.

Tank vs tankless lifespan

The two common types age very differently, because they work very differently.

Type	Typical lifespan	Why
Storage tank	About 8 to 12 years	Holds standing hot water, so minerals and corrosion build inside the tank
Tankless	About 15 to 20+ years	Heats on demand with little standing water, so less to corrode

Rheem gives 8 to 12 years for traditional tanks and 15 to 20 or more for tankless, and notes that most conventional tanks last around 10 years before replacement planning makes sense. Energy Star’s figure of a 20-year tankless life expectancy lines up with the high end. A tank fails sooner mainly because it always holds water, giving dissolved minerals a constant surface to settle on and corrode.

Signs your water heater is failing

A water heater usually warns you before it quits. Rheem lists these as the main signals, and any one of them is worth attention.

Age past 10 years. On its own, age is the strongest predictor. Once a tank is over a decade old, plan for replacement.
Rusty or discolored water. Brown or reddish hot water points to corrosion inside the tank or a spent anode rod. A rotten-egg smell suggests bacterial growth in the tank.
Rumbling or popping noises. Sediment hardening at the bottom of the tank makes it pop and rumble as it heats. That layer also cuts efficiency.
Leaks or pooled water. Water around the base of the tank often means corrosion has worked through the steel. An internal tank leak cannot be repaired, only replaced.
Not enough hot water. Running out faster than you used to can mean sediment buildup, a failing element, or a bad thermostat.
Rising energy bills. A failing heater often burns more energy to make the same hot water.

How to make it last longer

A tank heater that gets ignored for a decade tends to fail near the low end of its range. A little routine care pushes it toward the high end.

Flush the tank once a year. Draining the sediment out improves efficiency and extends tank life, per Rheem. It is the single highest-value task.
Check the anode rod every 3 to 4 years. This sacrificial rod corrodes so the tank does not. Replacing a spent rod is far cheaper than replacing the heater, and Rheem recommends this interval.
Keep water pressure in range. High household pressure stresses the tank and its connections. Rheem suggests aiming for 40 to 60 psi.
Descale a tankless unit yearly in hard water. Tankless heat exchangers scale up like a kettle, so an annual flush protects the long lifespan they are known for.

Repair or replace

When something goes wrong, the age of the unit usually decides the call. Rheem’s guidance: if a repair would cost more than 50 percent of a new unit, replacement is almost always the better investment. A heater already past 10 years is a poor candidate for repair, because another part is likely to fail soon after. A minor fix, like a thermostat or a heating element, on a heater still in its first several years is generally worth doing.

Water heaters involve gas, electricity, water, and pressure-relief safety. Confirm any repair-or-replace decision, and any install, with a licensed plumber and your local codes before you act.

To estimate where your specific heater sits in its lifespan, and roughly how many years it may have left, run it through our water heater lifespan calculator. To stay on top of the yearly flush and anode-rod checks, add it to the home maintenance tracker.

Sources

Energy Star · Whole-Home Gas Tankless Water Heaters, Benefits and Savings. energystar.gov/products/whole_home_tankless_gas_water_heaters/benefits-savings
Rheem · Water Heater Lifespan: When to Repair vs. Replace. rheem.com/water-heating/articles/water-heater-lifespan-when-to-repair-vs-replace
Rheem · 5 Signs Your Water Heater Is Going Bad. rheem.com/water-heating/articles/5-signs-your-water-heater-is-going-bad-and-what-to-do-about-it

Water heater lifespan calculator →

Frequently asked questions

How long does a tankless water heater last?

Tankless water heaters commonly last 15 to 20 or more years, and Energy Star gives a life expectancy of 20 years, longer than any conventional tank model. Because they do not store hot water, there is less standing water for minerals to corrode. Yearly descaling in hard-water homes helps them reach the top of that range.

Should I repair or replace my water heater?

A useful rule from Rheem: if the repair costs more than 50 percent of a new unit, replacement is almost always the better investment. Units already over 10 years old are poor candidates for repair, since another failure is likely soon after. A single cheap fix, like a thermostat, on a younger heater is usually worth doing.

What are the first signs a water heater is going bad?

Watch for age past 10 years, rusty or brown hot water, rumbling or popping noises from sediment, pooled water around the base, and running out of hot water faster than before. Rising energy bills for the same use can also signal a heater working harder than it should.