Where to find the serial number
- Tank heaters: on the rating plate, a sticker on the side of the tank, usually near the top or above the burner or element cover.
- Tankless heaters: on the label on the side or bottom of the unit. You may need to look from below.
- Can't reach it? Take a photo of the label with your phone and zoom in.
- Some labels print the manufacture date outright. If yours does, that date wins.
How to read the serial number, brand by brand
Rheem, Ruud or Richmond
Ignore any letters at the start. The next two digits are the month and the two after that are the year: 1209D01234 was made December 2009.
A.O. Smith
Newer serials start with the year then the week: 1210A002243 was made in week 10 of 2012.
State
Skip a leading S. The next two digits are the year and the two after are the week.
American Water Heater
The first two digits are the year and the next two are the week.
Reliance or U.S. Craftmaster
Same format as A.O. Smith: year, then week.
Whirlpool
The first two digits are the year and the next two are the week: 1104T403904 is week 4 of 2011.
Lochinvar (2011 and newer)
Since 2011 Lochinvar uses the A.O. Smith format: year, then week.
Bradford White
The first letter is the year and the second is the month (A is January, skipping I). DG6322957 was made July 2007.
GE
Ignore the letters at the start. The next two digits are the month and the two after are the year.
Kenmore
Kenmore heaters were made by several companies. A letter then two digits means month letter then year (J06 = September 2006).
Rinnai (tankless)
Since 2009 the first letter is the year (A = 2009) and the second is the month: BL is November 2010.
Navien (tankless)
Characters 6 and 7 are the year and character 8 is the month (X, Y, Z are October to December).
Noritz (tankless)
Starts with the full year then the month: 2005.06 is June 2005.
Takagi (tankless)
Since 2010: the first two digits are the year and the next two the week. Older serials don't contain a date.
How long they last in Florida
| Type | Typical life |
|---|---|
| Electric tank water heaters | 8 to 12 years |
| Gas tank water heaters | 8 to 12 years |
| Heat pump water heaters | 10 to 15 years |
| Tankless water heaters | 15 to 20 years |
Florida's water and year-round use put most tank heaters at the low end of national ranges. A tank past about 10 years is in the window where most fail, usually with a leak. Heat pump and tankless heaters last longer.
Common questions
How long does a water heater last in Florida?
A tank heater usually lasts 8 to 12 years, about 10 on average. Heat pump water heaters last 10 to 15 years and tankless units 15 to 20 or more.
What are the signs my water heater is failing?
Rust-colored hot water, rumbling or popping noises, water around the base, and hot water that runs out faster than it used to. Any leak from the tank itself means it's time to replace it.
Should I replace a water heater before it fails?
If it's past 10 years, usually yes. A planned replacement costs less than an emergency one, avoids water damage, and lets you choose a more efficient heater.
Does an old water heater affect my insurance?
Florida insurers may ask the water heater's age on a 4-point inspection. Our 4-point inspection check shows what they may ask about your home.
What if my brand isn't listed?
Most store brands are made by Rheem, A.O. Smith or Bradford White. Send us a photo of the label and we'll read it for you.
Sources
Rheem: how to read Rheem serial numbers · Bradford White: serial number date codes · A.O. Smith: manufacturing date · Building-Center.org · InterNACHI life expectancy chart. Formats can vary on very old or unusual units; the date printed on the label always wins.