Which Water Heater Brand Is Your Serial From?
Most people searching "water heater serial number lookup" have the serial in hand but not the brand knowledge — and every manufacturer encodes the date differently. This page solves exactly that: paste the serial and it identifies the format for you.
How it works: the detector above runs your serial against every decoder on this site at once:
- Rheem (plus Ruud, Richmond, GE, and other Rheem-built labels) — month + year digits after a letter prefix
- A.O. Smith (plus State, Reliance, American, Kenmore in most eras) — year + week digits
- Bradford White — two-letter code with a 20-year repeating cycle
- Navien, Rinnai, Bosch (tankless) — each with its own date-code scheme
When it matches, you get the decoded date immediately plus a link to the brand's full page, where the same serial is decoded with worked examples and warranty context. When it can't match, it tells you what to check instead of guessing.
Why a Serial Lookup Beats the Alternatives
- Receipts lie — a tank can sit in distribution for months after the manufacture date, and warranties run from the date of manufacture, not installation.
- Model numbers don't encode dates — only the serial does.
- Every brand hides the date differently — Rheem puts the month first, A.O. Smith puts the year first, Bradford White uses letters that repeat every 20 years. The same-looking serial decodes differently by brand, which is exactly why the detector above exists.
What You Get After Decoding
Once you know the manufacture date: the tank's age against the typical 8–12 year service life, whether a warranty claim is still possible (most warranties run 6–12 years from the manufacture date), and how urgently to plan a replacement. A 14-year-old tank is days from a $1,600–$3,000 replacement decision — knowing the date lets you make it calmly instead of during an emergency.
Sources
Serial formats on this page are compiled from our own decoder implementations, each verified against manufacturer and industry references: the InterNACHI water heater dating chart, Rheem's guide to reading serial numbers, A.O. Smith's production-date guidance, and Bradford White's serial-number guidance.