How old is my American Water Heater water heater?
Serial number age decoder for American Water Heater tank water heaters: 6 format eras, the decode rule in plain English, transcribed tables, and the official lookup.
Type the serial from the data plate, not the model number. Nothing is sent anywhere; the tables are in this page.
Format example: 1210A002243
- American Water Heater water heater serial numbers in the 2008 to present format encode the year as digits 1-2 (YY) after optional leading S and the week as digits 3-4 (source: building-center.org).
- Example: serial 1210A002243 decodes to week 10 of 2012.
- American Water Heater water heater serial numbers in the 2008 to present format encode the year as digits 1-2 (YY, 20YY) after any leading letter and the week as digits 3-4 (source: building-center.org).
- Example: serial 1924115263020 decodes to week 24 of 2019.
- American Water Heater water heater serial numbers in the before 2007 format encode the year as digits 1-2 (YY) and the month as digits 3-4 (building-center American style 1; GSW/John Wood FAQ: month before 2008) (source: building-center.org).
- Example: serial 05035 35368 decodes to March 2005.
- American Water Heater's official lookup at americanwaterheater.com returns warranty status.
Format eras
- before 2010 VERIFIED
A##A######digits 2-3 - 2008 to present VERIFIED
####A######digits 1-2 (YY) after optional leading S - 2008 to present VERIFIED
#############digits 1-2 (YY, 20YY) after any leading letter - before 2008 VERIFIED
AA##A######digits 3-4 - before 2007 VERIFIED
##### #####digits 1-2 (YY) - 1970 to 1979 VERIFIED
A##-A-##-######2 digits between hyphens (78)
How to read the serial
before 2010 formatVERIFIED
Shape A##A###### · example E07A135491 · confidence medium
- Year
- digits 2-3
- Week or month
- month = letter 1 (A=Jan..)
| Month code | Month |
|---|---|
| A | January |
| B | February |
| C | March |
| D | April |
| E | May |
| F | June |
| G | July |
| H | August |
| I | September |
| J | October |
| K | November |
| L | December |
Example: serial E07A135491 decodes to May 2007.
Listed under A.O. Smith in the source; American Water Heater is named in that format's family.
2008 to present formatVERIFIED
Shape ####A###### · example 1210A002243 / S1318 F000046 / 1836111786352 · confidence high
- Year
- digits 1-2 (YY) after optional leading S
- Week or month
- week = digits 3-4
- Plant
- letter after the 4 date digits (unpublished)
Example: serial 1210A002243 decodes to week 10 of 2012.
Listed under A.O. Smith in the source; American Water Heater is named in that format's family.
2008 to present formatVERIFIED
Shape ############# · example 1924115263020 / 1104T403904 · confidence high
- Year
- digits 1-2 (YY, 20YY) after any leading letter
- Week or month
- week = digits 3-4
- Plant
- letter after the date digits when present (unpublished)
Example: serial 1924115263020 decodes to week 24 of 2019.
before 2008 formatVERIFIED
Shape AA##A###### · example AF04A093001 / GG03-1495366-S29 · confidence medium
- Year
- digits 3-4
- Week or month
- month = letter 2 (A=Jan..)
- Plant
- letter 1
| Month code | Month |
|---|---|
| A | January |
| B | February |
| C | March |
| D | April |
| E | May |
| F | June |
| G | July |
| H | August |
| I | September |
| J | October |
| K | November |
| L | December |
Example: serial AF04A093001 decodes to June 2004.
Listed under A.O. Smith in the source; American Water Heater is named in that format's family.
before 2007 formatVERIFIED
Shape ##### ##### · example 05035 35368 / U0106413635 · confidence medium
- Year
- digits 1-2 (YY)
- Week or month
- month = digits 3-4 (building-center American style 1; GSW/John Wood FAQ: month before 2008)
Example: serial 05035 35368 decodes to March 2005.
1970 to 1979 formatVERIFIED
Shape A##-A-##-###### · example A20-H-78-015482 · confidence medium
- Year
- 2 digits between hyphens (78)
- Week or month
- month = letter between hyphens (H=Aug)
| Month code | Month |
|---|---|
| A | January |
| B | February |
| C | March |
| D | April |
| E | May |
| F | June |
| G | July |
| H | August |
| I | September |
| J | October |
| K | November |
| L | December |
Example: serial A20-H-78-015482 decodes to August 1978.
Listed under A.O. Smith in the source; American Water Heater is named in that format's family.
Where the data plate is on a water heater
The rating plate is a large label on the side of the tank near the top or beside the control. The serial is printed on it, often beside the model number and the ANSI standard line.
General guidance, not brand-specific: the owner's manual or the installer can point to the exact spot. See the data plate guide.
For scale only: the InterNACHI Standard Estimated Life Expectancy Chart for Homes lists Water Heater (conventional) at 6 to 12 years of expected service (nachi.org). That chart is a guideline, not a prediction for your unit.
Open the official American Water Heater lookup takes serial; returns warranty status; URL verified live
This site is a reference built from published tables. The manufacturer's own lookup wins whenever the two disagree.
What we could not confirm
- Johnson City, TN on the plate. Distributed under dozens of brands (Whirlpool, U.S. Craftmaster, Craftmaster, Lowes, Proline, Premier, Polaris, Champion...). Current style = A.O. Smith YYWW.
Sources
- https://www.building-center.org/a-o-smith/
- https://www.building-center.org/american-water-heater-age/
- https://www.building-center.org/whirlpool-water-heater-age/
- https://www.building-center.org/u-s-craftmaster-water-heater-age/
- https://www.building-center.org/craftmaster-water-heater-age/
- https://johnwoodwaterheaters.com/faqs/official
- https://gsw-wh.com/faq/official
- https://www.americanwaterheater.com/support/warranty-verification.htmlofficial