Since you probably understand that appliances don’t last forever, one of the first questions you’ll ask yourself when something goes wrong is, “How old is my water heater?“.
You may be wondering if repair or replacement is the best option or even if you’re still covered by the manufacturer’s warranty.
If you’re the type who saves every purchase receipt for decades, you probably don’t need to read this. If you have a newer model, the water heater age is sometimes clearly printed on the manufacturer’s label affixed to the unit.
For everyone else, keep reading to see how easy it is to find your water heater’s manufacture date. All you need is to know who manufactured the water heater and its serial number (both found on the label affixed to the water heater).
Alternatively, you can check your manual to get a rough estimate on age based on the copyright year. You can access online versions of most models of the three most popular brands at these links:
Manufacturer vs Brand
Note: This post may contain affiliate links. This means that at no cost to you, we may receive a small commission for made purchases.
Before going further, I want to point out the differences between a water heater manufacturer and a water heater brand. The manufacturer is the company that takes materials or components to create (or manufacture) the water heater.
The brand on the other hand is what the water heater is sold (or branded) as to customer. A small number of manufacturers create water heaters which are then sold under dozens of different brands. For instance, even though the water heater you bought from Sears says Kenmore on it, it’s still manufactured by Rheem.
So, how old IS my water heater?
Below are serial number lookup sections for every major water heater manufacturer. Column one lists all the various brands that manufacturer makes, column two shows sample serial numbers, and column three of each table acts as a serial number decoder.
A.O. Smith Water Heater Age
| Included Brands | A.O. Smith Serial Numbers | How to Decode |
|---|---|---|
| A.O. Smith Glascote GSW PermaGlas |
Style 1 (current): 1510******* (10th week of 2015) Style 2 (pre-2008): *A07******* |
Style 1: Digits 1-2 are the year and digits 3-4 are the week of the year.
Style 2: The second digit is the month (A-N, excluding I) so A=January and N=December. Digits 3-4 are the year. |
Rheem Water Heater Age
| Included Brands | Rheem Serial Numbers | How to Decode |
|---|---|---|
| Rheem Ruud Rheem/Ruud Richmond Vista Therm Citation Aqua Therm Energy Master Vanguard Cimarrom Coast to Coast Lowe’s Servi-Star True Value ABS Intertherm & Miller Mainstream Montgomery Ward General Electric Professional |
Style 1: 0811****** (August, 2011) Style 2: *3210***** Style 3: ** 1599****** Style 4: ****0608****** Style 5: 09.04-****** |
Style 1: Digits 1-2 are the month and digits 3-4 are the year.
Style 2: Digits 2-3 are the week of the year and digits 4-5 are the year. Style 3: Digits 3-4 are the week of the year and digits 5-6 are the year. Style 4: Digits 5-6 are the month and digits 7-8 are the year. Style 5: Digits 1-2 are the year and digits 3-4 are the month (the sets of numbers are separated by a period) |
Bradford White Water Heater Age
| Included Brands | Bradford White Serial Numbers | How to Decode |
|---|---|---|
| Bradford White Jetglas |
EH******* (August, 2008) TB******* |
1st letter equals the year using this key: P = 2017 | N = 2016 | M = 2015 L = 2014 | K = 2013 | J = 2012 H = 2011 | G = 2010 | F = 2009 E = 2008 | D = 2007 | C = 2006 B = 2005 | A = 2004 | Z = 2003 Y = 2002 | X = 2001 | W = 2000 T = 1999 | S = 1998 | P = 1997 2nd letter equals the month using this key: |
State Industries Water Heater Age
| Included Brands | State Ind. Serial Numbers | How to Decode |
|---|---|---|
| State/Kenmore Ace Ambassador Barnett Century Crosley Energy Stretcher Freedom Freedome/Nipsco Hardware House Master Plumber/True5 Mission Nationaline Patriot Penfield President Regency Reliance The Plumbery Thermo-Ki |
Style 1: 1021******* (21st week of 2010) Style 2: K06******* Style 3: *K06******* |
Style 1: Digits 1-2 are the year and digits 3-4 are the week of the year.
Style 2: The 1st digit is the month of the year using the key below and digits 2-3 are the year. Style 3: Same as style 2 except it has an extra digit at the beginning. |
American Water Heater Age
Acquired by A.O. Smith in 2001. Prior to that, manufactured water heaters for dozens of different brands.
| Included Brands | American Serial Numbers | How to Decode |
|---|---|---|
| American Water Heaters Ace American Hardware Best Best Deluxe Apex Aqua Temp Agua Therm Aquamatic Champion Craftmaster De-Limier Deluxe Eagle Earl’s Energy Saver Environtemp Four Most Hotmaster Hotstream King-Cleen King-line Master Plumber Mor-Flo/American Nationaline Neptune Penquin Premier Prestige Proline Proline-Plus Quaker Quick-Flo Raywall Revere Riveria SABH Sands Sentinel Service-Star Shamrock Special Deluxe Standard Super Eagle Sure-Fire Thoro-clean Tru-Test Tru Value U.S. Supply Whirlpool XCL-Energy Saver |
Style 1 (current): 1510******* (10th week of 2015) Style 2 (pre-2008): *A07******* |
Style 1: Digits 1-2 are the year and digits 3-4 are the week of the year.
Style 2: The second digit is the month (A-N, excluding I) so A=January and N=December. Digits 3-4 are the year. |
Lochinvar Water Heater Age
| Included Brands | Lochinvar Serial Numbers | How to Decode |
|---|---|---|
| Lochinvar Energy Saver Golden Knight Knight |
EH******* (August, 2008) TB******* |
1st letter equals the year using this key: P = 2017 | N = 2016 | M = 2015 L = 2014 | K = 2013 | J = 2012 H = 2011 | G = 2010 | F = 2009 E = 2008 | D = 2007 | C = 2006 B = 2005 | A = 2004 | Z = 2003 Y = 2002 | X = 2001 | W = 2000 T = 1999 | S = 1998 | P = 1997 2nd letter equals the month using this key: |
