---
title: "How Long Do Water Heaters Last? | What Year Is"
description: "Tank water heaters typically last 8 to 12 years by one maker’s count and about 15 on DOE’s average. Tankless last longer. How to tell how old yours is."
canonical: "https://whatyearis.com/how-long-do-water-heaters-last"
markdown: "https://whatyearis.com/how-long-do-water-heaters-last.md"
last_updated: "2026-10-19"
---

# How long do water heaters last?

A tank water heater typically lasts 8 to 12 years, according to Rheem, and the U.S. Department of Energy puts the average life of a storage water heater at around 15 years. Tankless water heaters last longer: ENERGY STAR gives them a life expectancy of 20 years. To know where yours stands, find its build date in the serial number on the rating plate.

By [the What Year Is team](https://whatyearis.com/editorial) · Updated October 19, 2026

## Why do the numbers differ?

They measure different things. Rheem’s 8 to 12 years is what a manufacturer calls a typical service life. The Department of Energy’s figure is a statistical average across every storage water heater in its analysis, including the long-lived ones, so it runs higher. Both are averages: any one tank can fail sooner or last well beyond them.

## How long do tankless water heaters last?

Longer than tanks. ENERGY STAR gives gas tankless water heaters a life expectancy of 20 years, and Rheem says tankless units can last 15 to 20 years or more with proper care.

## Does the warranty tell you how long a water heater will last?

Not directly, but it tells you what the maker stands behind. Bradford White’s residential tank warranties run 1, 6, 8 or 10 years depending on the model, and the model number on the rating plate says which one you have. A longer warranty usually means a better-built tank, not a guaranteed life.

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

Read the serial number on the rating plate, the label on the side of the tank. Most manufacturers code the build date into it, but each does it differently:

- [Bradford White](https://whatyearis.com/bradford-white-water-heater): the first two letters are the year and month.
- [A.O. Smith](https://whatyearis.com/ao-smith-water-heater): the first four digits are the year and week.
- [Lochinvar](https://whatyearis.com/lochinvar-water-heater): the first four digits are the year and week on tanks made since 2011.

The build date is usually a little earlier than the install date, since a water heater can sit in a warehouse before it’s installed.

## Sources

- [Water Heater Lifespan: When to Repair vs. Replace](https://www.rheem.com/water-heating/articles/water-heater-lifespan-when-to-repair-vs-replace/), Rheem Manufacturing Company. Traditional tank water heaters typically last 8 to 12 years; tankless water heaters can last 15 to 20 years or more with proper care.. Checked October 19, 2026.
- [Energy Conservation Program: Energy Conservation Standards for Consumer Water Heaters (final rule, April 2024)](https://www.energy.gov/sites/default/files/2024-04/cwh_fr1.pdf), U.S. Department of Energy. DOE estimates the average product lifetime to be around 15 years for storage water heaters.. Checked October 19, 2026.
- [Save More with ENERGY STAR Gas Tankless Water Heaters](https://www.energystar.gov/products/whole_home_tankless_gas_water_heaters/benefits-savings), ENERGY STAR (U.S. EPA and DOE). Tankless water heaters have a life expectancy of 20 years.. Checked October 19, 2026.
- [Limited Residential Water Heater Warranty (238-39699-00)](https://docs.bradfordwhite.com/Warranty/238-39699-00_Current.pdf), Bradford White Corporation. Bradford White’s glass-lined tank warranty is 1, 6, 8 or 10 years from installation, depending on the model.. Checked October 19, 2026.

## Related pages

- [How old is my Bradford White water heater?](https://whatyearis.com/bradford-white-water-heater): The first two letters of a Bradford White serial number are the year and month it was built. Here’s the letter chart, with worked examples.
- [How old is my A.O. Smith water heater?](https://whatyearis.com/ao-smith-water-heater): On a current A.O. Smith water heater, the first four digits of the serial number are the year and week it was built. Here’s how to read them.
- [How old is my Lochinvar water heater or boiler?](https://whatyearis.com/lochinvar-water-heater): How to read the build year and week from a Lochinvar water heater or boiler serial number, from Lochinvar’s own warranty guide, with worked examples.
- [How old is my Bradford White water heater?](https://whatyearis.com/bradford-white-water-heater): The first two letters of a Bradford White serial number are the year and month it was built. Here’s the letter chart, with worked examples.
- [How old is my A.O. Smith water heater?](https://whatyearis.com/ao-smith-water-heater): On a current A.O. Smith water heater, the first four digits of the serial number are the year and week it was built. Here’s how to read them.
- [How old is my Lochinvar water heater or boiler?](https://whatyearis.com/lochinvar-water-heater): How to read the build year and week from a Lochinvar water heater or boiler serial number, from Lochinvar’s own warranty guide, with worked examples.
- [How long does a furnace last?](https://whatyearis.com/how-long-does-a-furnace-last): Manufacturers put a typical furnace life at 15 to 20 years, and DOE’s average for gas furnaces is 21.5 years. Here’s how to tell how old yours is.

## About this document

This is the Markdown version of a page on What Year Is (https://whatyearis.com). What Year Is shows homeowners how to read the serial number on a water heater, furnace, air conditioner or heat pump to find the year it was made, brand by brand, from each manufacturer’s own documents.

- Site index for AI assistants: https://whatyearis.com/llms.txt
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