How old is my Rheem tankless water heater?
Serial number age decoder for Rheem tankless water heaters: 1 format era, the decode rule in plain English, transcribed tables, and the official lookup.
Type the serial from the data plate, not the model number. Nothing is sent anywhere; the tables are in this page.
Format example: 0804B10488
- Rheem tankless water heater serial numbers in the era not stated format encode the year as digits 3-4 (YY) and the month as digits 1-2 (MMYY prefix) (source: building-center.org).
- Example: serial 0804B10488 decodes to August 2004.
- Rheem's official lookup at rheem.registermyunit.com returns warranty terms and coverage.
Format eras
- era not stated VERIFIED
####A#####digits 3-4 (YY)
How to read the serial
era not stated formatVERIFIED
Shape ####A##### · example 0804B10488 · confidence high
- Year
- digits 3-4 (YY)
- Week or month
- month = digits 1-2 (MMYY prefix)
- Plant
- letter at position 5
Example: serial 0804B10488 decodes to August 2004.
Where the data plate is on a tankless water heater
On the side or bottom of the wall-hung cabinet, or inside the front cover on the frame.
General guidance, not brand-specific: the owner's manual or the installer can point to the exact spot. See the data plate guide.
For scale only: the InterNACHI Standard Estimated Life Expectancy Chart for Homes lists Instant (on-demand) Water Heater at 10 years of expected service (nachi.org). That chart is a guideline, not a prediction for your unit.
Open the official Rheem lookup takes serial number; returns warranty terms and coverage; URL verified live
This site is a reference built from published tables. The manufacturer's own lookup wins whenever the two disagree.
Sources
- https://www.building-center.org/rheem/
- https://www.rheem.com/faq/official
- https://rheem.registermyunit.com/en-US/warranty/brand?brand=rheemofficial
Frequently asked questions
How do I tell the age of a Rheem tankless water heater from the serial number?
In the era not stated format the year is digits 3-4 (YY) and the month as digits 1-2 (MMYY prefix). Example: serial 0804B10488 decodes to August 2004.
Where is the serial number on a Rheem tankless water heater?
On the data plate. On the side or bottom of the wall-hung cabinet, or inside the front cover on the frame.