State-brand water heaters, made by the same corporate parent as A.O. Smith, have a clearly documented older format and a current format that independent sources genuinely disagree about, so this page states both facts rather than picking a side without evidence. On State's legacy format, a single letter carries the month — A for January through M for December — followed directly by a two-digit year, so a serial beginning A00 reads as January 2000; multiple independent references agree on this reading with no contradicting example.
On State's modern all-numeric format, one detailed reference states month-then-year in the first four digits while other sources state year-then-week instead, and the same reference that documents the month-then-year reading explicitly flags that it has seen guides claiming the opposite order. This site could not resolve that disagreement with confidence, so the modern format is described here without a computed example, and confirming it through State's own support line is the more reliable path.
Try it
Decode your own serial number
What this covers
- State residential water heaters with the legacy serial format: a single month letter (A–M, skipping I) followed by a two-digit year
- State residential water heaters with a current all-numeric serial, where this page states the position of the date but does not compute a specific reading
What it does not cover
- ×A computed date from State's current all-numeric serial format — independent sources disagree on whether it reads month-then-year or year-then-week
- ×State commercial water heaters not separately confirmed
- ×Any assumption that State shares A.O. Smith's exact numeric format without independent confirmation
Try in this order
0 of 4 completedLocate the data tag
ReversibleCheck the exterior jacket of the tank for the rating/serial label.
Check for the legacy letter-month pattern first
ReversibleIf the serial opens with a single letter (A through M) immediately followed by two digits, read the letter as the month and the digits as the two-digit year. A00 means January 2000.
Treat an all-numeric serial as unresolved
ReversibleIf the serial is all digits, this page cannot confirm whether the first four digits read as month-then-year or year-then-week — do not guess between them.
Call State's own support line for a numeric serial
ReversibleState's own customer support can confirm the manufacture date directly from the serial number when this page's confirmed rule doesn't apply.
Evidence ledger
Sources behind this answer
Where the manufacturer's article stops. The cited reference documents the legacy format with a worked example and explicitly notes it has seen other guides claim the opposite digit order for the modern numeric format — that stated disagreement, not a guess of this site's own, is why the modern format is not decoded here with a specific example.
Exact questions
Questions about Decode a State water heater serial number
Which digit order is right for a modern State water heater serial?+
Published guides disagree: the reference for the legacy format notes that other guides claim the opposite digit order for the modern format, so neither reading can be given as fact.
Is State the same company as A.O. Smith?+
State Industries is owned by the same corporate parent as A.O. Smith, but this page has not independently confirmed that State's current numeric serial format is identical to A.O. Smith's.
How reliable is the legacy letter-month format?+
More reliable than the modern format on this page — multiple independent references agree on it with a consistent worked example and no contradiction found.
Where do I find the State water heater serial number?+
Look for the rating plate or label on the unit, on the rating plate on the tank. Photograph it before you start, since the label can be hard to read once the appliance is installed.