How to read a A. O. Smith, State, American, Reliance serial number (find the build date)

Decode a serial number now (works offline).

The rule

Digits 1–2 = year, digits 3–4 = week of the year (01–53). Example: 1719… = week 19 of 2017.

This rule comes from the maker: A. O. Smith Service and Warranty Guide (Dec 2018), p. 10.

Worked examples

1719106145074May 2017
0852A1234December 2008
2301XXXXJanuary 2023

Applies to: A. O. Smith, State, American and Reliance water heaters. Always check the result against the label.