Year + production week
1210A002243
Week 10, 2012 (around March).
Water heaters / State
How old is my State water heater?
StateChange
Ad 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 valveState 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
M07A009387
December 2007.
Coverage and sources
A leading S is a factory prefix in the S + year/week format; it is not a month. Older letter-month formats are supported only as listed.
References checked 2026-10-26.
Independent reference tool, unaffiliated with State. Sources & method