How to read a Rheem, Ruud serial number (find the build date)

Decode a serial number now (works offline).

The rule

Digits 1–2 = month (01–12), digits 3–4 = year, then a plant-line letter and the sequence number. Example: 1209D01234 = December 2009. Rheem’s page covers current serials only.

This rule comes from the maker: Rheem, "How to Locate and Read your Rheem Water Heating Serial Numbers".

Worked examples

Applies to: Rheem and Ruud water heaters. Always check the result against the label.