How old is my A. O. Smith water heater?
A. O. Smith water-heater serial numbers begin with the date as four digits: the first two are the year and the next two are the week of manufacture.
The same decoder works for: State, Reliance, American Water Heaters, U.S. Craftmaster, Whirlpool (water heaters), Kenmore (water heaters), GE (water heaters).
Free. The serial is on the metal nameplate or rating label, usually near the bottom of the unit.
A. O. Smith serial-number formats
| Era | Format | Confidence |
|---|---|---|
| 1990s–present | a serial that starts with two-digit year then two-digit week (YYWW), sometimes after a leading letter | high |
Worked examples
1542A001234
→ manufactured around October 2015 (about 11 years old). Read as a serial that starts with two-digit year then two-digit week (YYWW), sometimes after a leading letter. Decoded value 42 (position group 2), year 2015 (digits "15"), month ~October (approximated from week 42) → manufactured around October 2015, about 11 years old.
Frequently Asked Questions
How do I find the age of my A. O. Smith unit?
A. O. Smith water-heater serial numbers begin with the date as four digits: the first two are the year and the next two are the week of manufacture. Enter the serial from the unit's nameplate into the decoder on this page and it returns the manufacture date and age instantly. Always confirm against the manufacture date printed on the nameplate.
Where is the serial number on a A. O. Smith water heater?
The serial number is printed on the metal data plate or rating label, usually near the bottom or on the side of the unit. It is labeled "Serial," "Serial No.," or "S/N." Do not confuse it with the model number.
Is the A. O. Smith serial-number date exact?
It identifies the manufacture date, not the install date — a unit is often installed weeks or months after it was built. Verify against the manufacture date on the nameplate when one is printed.
Developers & AI agents: the A. O. Smith decode rules are available as JSON.
Serial-number decoding is approximate. Results are estimates based on published manufacturer formats; always verify against the manufacture date printed on the unit nameplate. ApplianceAge is a CarWhere tool and is not affiliated with, endorsed by, or sponsored by any manufacturer. Brand names are used only to identify the equipment a serial belongs to.