The manufacturer's warranty period, as well as a description of what is covered under the warranty, are clues both to the importance of water heater maintenance and hints about how long the company expects their water heater tank to last.

Typical water heater warranty periods for a water heater installed for use by a single-family are 6-years, 9-years, or 12-years. Tankless water heaters have a typical life expectancy of more than 20 years. The warranty period of a water heater may be encoded in its model or serial number.

For example, some manufacturers like U.S. CraftMaster water heaters include an indicator on the label of your water heater that tells how long your specific warranty period is. If the water heater is in any other use than one-family residential, the heater is warranted for one year on parts and three years on the tank itself (commercial applications).

Watch out: if the water heater tank leaks and fails before the end of the warranty period, if the system has not been properly installed or maintained the warranty may be void. Water heater warranties typically indicate that the tank is warranted against leaks due to rust, corrosion, or chemical action of the water but the warranty will exclude a tank failure due to scale.

Watch out: as well to perform the manufacturer's recommended water heater maintenance chores. Flushing a water heater on schedule, checking and replacing the water heater anode when required, and attention to the water quality in the home - corrosivity and mineral level, for example, can make a significant difference in the water heater's life.

Common Water Heater Brands installed in the United States Include:

American, AO Smith, Bosch, Bradford White, Lochinvar, Marathon (Rheem), Navien, Reliance, Rheem, Rinnai, Ruud, Sears/Kenmore, State Industries, Stiebel, U.S. Craftmaster & Whirlpool.