A water heater attached to a purple wall.

How Long Do Water Heaters Last on Average?

If you know the age and condition of your water heater, this can help you better predict how long it will last. You can save yourself an unexpected cold shower by simply replacing it when the time has come. Not only will replacing it keep the warm water continuously flowing, but you may also see lower energy costs on your monthly bills. 

Average Lifespan

So how long does a water heater last? A traditional tank-type water heater can last anywhere from 6 to 13 years. Typically manufacturers suggest the tank can last from 8 to 12 years. For a tankless water heater, the lifespan is much longer, lasting up to 20 years or more. The life expectancy of water heaters will vary, depending on some factors we will discuss later. 

We recommend that you start thinking about replacement two years before the highest end of the life span. This would be 8 to 10 years of age for tank-style water heaters, and 15 to 18 for a tankless one. Replacing earlier than necessary will allow you the inconvenience of going without hot water, and also conserve more energy when a new one is installed. 

Older water heaters tend to have mineral deposits and sediment buildup in them, which require more power to heat the water. A new model will be more efficient and save you any money you thought you were saving by keeping the old one. But what happens if you aren’t sure of the age of your water heater?

Determining Age of Your Water Heater

Perhaps you have moved into a new home and you aren’t sure of the age of the existing water heater. Or perhaps the year you purchased your water heater has slipped your mind. Not to worry, you can determine the age simply by looking at the serial numbers on the unit. On the upper portion of the unit, you can find the serial number which will have a letter, then a series of numbers. These numbers indicate when the water heater was manufactured.

The letter usually stands for the month it was made. For instance, “A” would indicate it was manufactured in January, “B” for February, etc. The two numbers following the letter will represent the year the unit was made. For example, “C19” would indicate the water heater was produced in March 2019. Be aware that this rule applies to most, not all, water heater manufacturers. 

An electric heating element covered in limescale.

Water that has high mineral content (also known as hard water) causes limescale deposits that reduce water heater lifespan.

Factors Influencing Water Heater’s Lifespan

Quality of installation:

Your water heater should be installed upright in a well-ventilated area. Not only is this important for fire safety and carbon monoxide buildup, but a unit with restricted ventilation can shorten its lifespan. 

Regular maintenance:

Draining and flushing the tank, as well as getting regular service checks can help extend your unit’s longevity. Preventing calcium buildup, leaks, and rust will also add to the overall efficiency of the water heater.

Water quality:

Hard water can harm your unit, reducing its lifespan by two years or more. 


A water heater in a garage or crawl space, or anywhere where the temperature is low, will cause the unit to work harder and require more energy. These units tend to expire faster than ones that are inside a temperature-controlled environment. 


The more affordable units will usually have a shorter lifespan. It is worth it to buy a more expensive model that will last longer. A longer warranty usually indicates better construction. 

A water heater being repaired with a wrench.

Professional installation and routine maintenance of your water heater can increase its lifespan.

How to Extend the Life of Your Water Heater

Some of these factors you may have no control over. However, the maintenance of the unit is entirely in your hands. Luckily, today’s water heaters don’t need much special attention. Here are some tips that could help aid in your unit’s longevity:

  • Twice a year, drain the unit to get rid of any sediment that has built up. This prevents corrosion and also allows it to work more efficiently. 
  • Test the pressure valve. You can do this by lifting the handle and then letting it spring back into place. The overflow drain pipe should receive a burst of water as a result. If this doesn’t occur, this may mean you need a new valve. 
  • To reduce the risk of damage due to overheating, lower the tank’s temperature to 120 degrees Fahrenheit. 
  • Consider purchasing and installing a water softener to reduce scale buildup in your water heater. 

Signs to Replace

Besides reaching an age between 6 and 13, some other signs that you may need to replace your water heater are as follows: 

  • Tinted water: If the water has a red or yellow tint to it, it may mean there is rust in your water heater. It may also start to show signs of wear and start to leak. If the water is tinted even when the cold water is running, this might point instead to rusting galvanized pipes. If not, it is a sign that the water heater is the problem.
  • Creaking, gurgling, banging noises: Noises start to emanate from the unit if calcium buildup has been collected at the bottom of the tank. This usually happens at the end of the water heater’s lifespan. A good way to prevent this problem is to annually flush the unit. After draining the tank, you can remove and soak the parts in white vinegar for about an hour and then scrape off the residue.
  • Dampness or water pooling at the base: If you feel any dampness or notice any pooling water at the bottom of the unit, this could signal a leak. First, make sure the leak isn’t from a fitting or valve that needs to be tightened or replaced. If you rule that out, the leak is most likely coming from the tank due to cracking or corroding inside. Oftentimes you will start to see leaks around the tank’s base after 10 years of use.
  • No hot water: If there is no hot water, or very little, this could mean that your unit has reached the end of its lifespan.

If any of these or other problems are occurring, the first rule out any electrical issues like a blown fuse or a tripped breaker. If that isn’t the case, you may need a new water heater. Be sure to check with your manufacturer to see if the unit is still under warranty. If the unit is only a few years old, you may still be able to have it fixed. Keep that in mind before you go buy a new one. We wish your water heater a long life.

Joshua Perkins

Joshua spent ten years as a water systems technician in California before settling down with his wife and two young children in Nashville in 2018. Through all of his experience, he learned the benefits and shortfalls of so many different types of water filtration systems, from pitchers to whole-house installations. He started Water Filter Authority in 2019 to empower other families to make the right decision for their long-term health and wellness.