How old is my Rheem tankless water heater?
Enter the serial number from the label. The date comes from Rheem's documented serial rules, not a guess.
How to read a Rheem tankless water heater serial number
Plant letter + week + year (2012 onward)
Month + year + plant code (before 2012)
Not decoded yet: Older Paloma-built tankless serials (e.g. 05.05-000021) and some 16-character serials are not decoded because sources disagree. If the label prints a MFG DATE, that date is authoritative.
Where to find the serial number
The rating label is on the side of the unit's cabinet. Some models also show it behind the front cover.
Rheem tankless water heater model numbers
If the brand name isn't visible on the label, the model number can help. Model numbers like these follow Rheem's published nomenclature:
- ECO160DVLN3, ECO200XELN3, ECOHS160IN — Rheem Manufacturing tax-credit certificate ("RHEEM MODELS" / "RUUD MODELS" columns)
How long does a tankless water heater last?
A typical tankless water heater lasts about 15–20 years. That's a general estimate: maintenance, usage, climate and installation all matter, and age alone doesn't tell you a unit's condition. The U.S. Department of Energy estimates an average of about 20 years.
Range from A. O. Smith: how long do water heaters last? and U.S. DOE, gas-fired instantaneous water heater standards, 89 FR 105188 (2024).
Rheem tankless water heater recalls
- Rheem Recalls to Repair Water Heaters Due to Fire and Burn Hazards; Sold Exclusively at Home Depot (2016-05-26)
- LP Gas Water Heaters Repaired by White-Rodgers (1980-12-04)
From the U.S. Consumer Product Safety Commission, checked 2026-09-29. A decoded result checks your model number against recalls live.
Questions
- How can I tell how old my Rheem tankless water heater is?
- Find the serial number on the rating plate and enter it above. We decode it using Rheem's documented serial-number format.
- Where is the serial number on a Rheem tankless water heater?
- The rating label is on the side of the unit's cabinet. Some models also show it behind the front cover.
- How long does a tankless water heater usually last?
- A typical service life is about 15–20 years. That's a general estimate: maintenance, usage, climate and installation all matter, and age alone doesn't tell you a unit's condition.
- Do Ruud tankless water heaters use the same serial format?
- Yes. Rheem and Ruud use the same serial-number conventions (Rheem / Ruud water heaters), so the same decoding rules apply.
- How reliable is the result?
- The Rheem / Ruud water heaters rules come from documented sources, but they're in Beta while we check more real-world examples, so results are capped at medium confidence. If a serial doesn't match a documented format, we say so instead of guessing.
Related
Same serial format: Ruud tankless water heater
Other Rheem equipment: furnace, air conditioner, heat pump, water heater
Sources
- Rheem Technical Service Bulletin 1207: How to locate and read Rheem/Ruud/Richmond serial numbers
- CPSC 2016: Rheem water heater recall (serial date codes)
- Rheem: How to locate and read your water heating serial numbers
Rules last reviewed 2026-09-28. These rules are in Beta while we verify more real-world examples, so results are capped at medium confidence.
Manufacture dates are decoded from manufacturer serial-number conventions and available documentation. Serial formats can change. Verify critical equipment information with the manufacturer when necessary.