Year + production week
1210A002243
Week 10, 2012 (around March).
Water heaters / A.O. Smith
How old is my A.O. Smith water heater?
A.O. SmithChangeAd space (kept empty until an ad network is approved)
Where to find the serial number
Look for “Serial No.” on the label above the gas valveA.O. Smith serial formats we can read
Dark = year, orange = month or week.
S prefix + year/week
S1318F000046
Week 18, 2013 (around May).
Factory + month letter + year
AF04A093001
June 2004.
Month letter + year
E07A135491
May 2007.
Coverage and sources
Supports the listed year/week and older month-letter formats. Other discontinued layouts are not decoded.
References checked 2026-10-26.
Independent reference tool, unaffiliated with A.O. Smith. Sources & method