How to read a State serial number
State is an A.O. Smith brand, and its serials follow the same two patterns [1][2]. What the serial starts with tells you which one you have.
| Serial starts with | Means | Example |
|---|---|---|
| Four digits | Digits 1–2 = year, digits 3–4 = week of the year (about 2008 on) | 1735107397129: week 35 of 2017, late August |
| A letter, then two digits | Letter = month (A = January … M = December, no I), digits = year | M07A009387: December 2007 |
| Two letters, then two digits | Same, with a factory letter in front (dropped after July 2004) | Read the second letter as the month |
The month letters are the same table A.O. Smith uses [1][3][4]. One InterNACHI example reads J as October; the rule and the other charts make it September, which is what the decoder uses.
A caption that doesn’t match its own rule
Energy Trust of Oregon’s chart shows a State serial beginning 0904 and captions it “April 2009” [2]. Its own rule for this style says the digits are year and week, which makes 0904 the 4th week of 2009, late January. The Building Intelligence Center reads it the same way [1]. We follow the rule, so 0904 decodes to late January 2009.
Worked examples
| Serial | Style | How it reads | Made | Example from |
|---|---|---|---|---|
1735107397129 | Year + week first (about 2008 on) | 17 = year ’17; 35 = week 35 of the year | Week 35 of 2017 (around August) | Building Intelligence Center |
0904A123456 | Year + week first (about 2008 on) | 09 = year ’09; 04 = week 4 of the yearCaption on the source says April 2009; see note. | Week 4 of 2009 (around January) | Energy Trust of Oregon |
H765662231 | Month letter + two-digit year (before about 2008) | H = month letter (August); 76 = year ’76 | August 1976 | Building Intelligence Center |
M07A009387 | Month letter + two-digit year (before about 2008) | M = month letter (December); 07 = year ’07 | December 2007 | Building Intelligence Center |
C05A1234567 | Month letter + two-digit year (before about 2008) | C = month letter (March); 05 = year ’05Energy Trust example C05******* filled in. | March 2005 | Energy Trust of Oregon |
J89123456 | Month letter + two-digit year (before about 2008) | J = month letter (September); 89 = year ’89InterNACHI captions "J89xxx" as October 1989; see the month-letter note. | September 1989 | InterNACHI |
Very old State tanks
The month-letter style goes back a long way: H765662231 is August 1976 [1]. Two-digit years only repeat every century, so these serials have a single answer, but a tank this old is worth having checked.
Where to find the serial number
On the rating plate label on the tank jacket. State tanks have also been sold under other names, including Reliance, Ambassador, Crosley and, in some years, Kenmore.
Common questions
How old is my State water heater?
Enter the serial above. If it starts with four digits, digits 1–2 are the year and 3–4 the week; if it starts with a letter, that letter (or the second one) is the month and the next two digits the year.
Why does the decoder show a week instead of a month?
Newer State serials record the week of the year, not the month. The decoder shows the month that week falls in.
Are State and A.O. Smith serials read the same way?
Yes. The A.O. Smith page has more examples of both styles.
Not affiliated with State Water Heaters or A.O. Smith. Brand names are used only to say which serials this decoder reads.
Sources
- Building Intelligence Center: STATE Water Heater AgeUsed for: Year + week first (about 2008 on); Month letter + two-digit year (before about 2008).
- Energy Trust of Oregon: Serial Number Decoder: Water Heater (PDF)Used for: Year + week first (about 2008 on); Month letter + two-digit year (before about 2008).
- InterNACHI (International Association of Certified Home Inspectors): InterNACHI Water Heater Dating ChartUsed for: Month letter + two-digit year (before about 2008).
- Honest Home Inspections, LLC (hosted by InspectAPedia): How to determine Water Heater and Furnace Age (PDF, last updated 2009-01-06)Used for: Month letter + two-digit year (before about 2008).