You can expect a tank-type water heater to last 10 to 20 years, with the average of 12 years. But there are four variables that affect the lifespan:

1) Quality of manufacture - As your would expect, the premium-priced water heaters with the longer warranties and features like a porcelain-lined tank, larger heating elements, and better insulation will hold up longer.

2) Rate of usage - A 40-gallon water heater serving a family of six is not going to last as long as one serving an older couple with no children.

3) Installation - A homeowner or handyman installation can shorten the life of a water heater, especially a gas-fired one. For more on correct installation, see our blog What are the most common installation mistakes with water heater replacement?

4) Maintenance - The simplest and easiest maintenance item is draining the water heater to flush out sediment accumulation at the bottom every two years, or sooner if you have a lot of sediment in the water. For more on water heater maintenance, see our blog What can I do to make my water heater last longer?. And for specific instructions on how to drain and flush out a water heater, go to our blog Why is my water heater making strange (rumbling, gurgling, knocking or banging) noises?   Most water heaters fail by leaking and we recommend that you give it a careful examination twice a year, looking for any telltale small, rust-colored drip strains on the top or sides, and especially around pipe connections—evidence of the beginning of tank failure.

    Here’s a bar graph that compares the life expectancy of a tank water heater to other home plumbing appliances.
   As your water heater ages, it can become an obstacle for getting or renewing homeowners insurance.  When insurance companies request a 4-point inspection for older homes, as they are doing more often lately, if the water heater is over about 25 to 30 years old they will request that it be replaced as a requirement for coverage. For the statistics on why insurance companies get hot about water heater replacement, read our blog Why is an older water heater an insurance problem?

   If you are not sure how old your water heater is, enter the brand name of the water heater along with “water heater age” in the search box at the top of this page. 

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Field Guide for Home Inspectors, a quick reference for finding the age of 154 brands of HVAC systems, water heaters, and electrical panels, plus 210 code standards for site-built and manufactured homes, and the life expectancy rating of 195 home components. Available at amazon.com for $19.95.
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Here’s links to a collection of more blog posts about WATER HEATERS:

• Are water heaters required to be raised off the floor? 

• Can a Temperature and Pressure Relief (TPR or T&P) valve be mounted to discharge horizontally?

• Where are gas water heaters not allowed to be installed?  

• Is the minimum size water heater inlet pipe 1/2" or 3/4" according to the building code?

• Can you use a light switch for a water heater disconnect? 

• How can I tell if a water heater is HUD-approved for mobile/manufactured homes?

• Can you wire a 240-volt water heater with 120 volts? 

• Is it alright to have a shut-off valve on both the hot and cold water pipes at a water heater?  

• What is the minimum clearance to doors and windows for an outdoor tankless gas water heater? 

• What is required clearance for access and working space in front of an electric water heater? 

• Why is the water heater older than the house? 

• Does a water heater need a shut-off valve? 

• Why should a tankless water heater have an isolator/service valve kit installed?

• When was a gas water heater first required to be elevated 18 inches above a garage floor?  

• Can the temperature and pressure relief (TPR) valve discharge pipe for a mobile/manufactured home water heater terminate under the home? 

• What is the purpose of a thermostatic mixing valve above a water heater? 

• Does a tankless gas water heater still work with no electricity during a power outage?  

•  Why do water heaters have a sacrificial anode? 

• What is the difference between a manufactured/mobile home water heater and a regular water heater? 

• Does a tankless water heater require a pressure relief valve?

• When is a water heater drain pan required?

• Why is there water in my water heater drain pan?

• What does it mean when a water heater Temperature/Pressure Relief (TPR) discharge pipe is "trapped"? 

• Can I leave a gas water heater in place when remodeling a garage into a family room or bedroom? 

• Where do I find the water heater in a mobile home?

• Does a tankless water heater in an attic require a drain pan? 

• What's the valve with the flip-up handle on the water heater for?

• Why is an older water heater an insurance problem?

     Visit our WATER HEATERS and LIFE EXPECTANCY pages for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.