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Rheem / Ruud water heaters

How old is my Ruud water heater?

Enter the serial number from the label. The date comes from Ruud's documented serial rules, not a guess.

Look for “Serial No.” or “S/N” on the label. Spaces and dashes are fine.

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How to read a Ruud water heater serial number

Rheem’s own documents cover Ruud: its water-heater service bulletin is titled “How to Locate and Read Rheem/Ruud/Richmond Serial Numbers”, and Rheem/Ruud installation manuals list Ruud as one of the brands. We decode Ruud heating and cooling equipment and Ruud water heaters, but they use different serial formats, so choose the right equipment type before you decode.

  • Month + year + plant code (before 2012)

    Example: 1209D01234 (Ruud) was made in December 2009. On Rheem water heaters built before 2012, the serial starts with the month and then the year: "12" is December and "09" is 2009.

  • Plant letter + week + year (2012 onward)

    Example: M141209135 (Rheem) was made in April 2012. Since 2012, Rheem water-heater serials start with a plant letter ("M" = Mexicali), then two digits for the week and two for the year: week 14 of 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 tank: near the gas control valve on gas models, or above the upper heating-element cover on electric models.

Ruud water heater model numbers

If the brand name isn't visible on the label, the model number can help. Model numbers like these follow Ruud's published nomenclature:

How long does a water heater last?

A typical water heater lasts about 8–12 years. That's a general estimate: maintenance, usage, climate and installation all matter, and age alone doesn't tell you a unit's condition.

Range from A. O. Smith: when to repair or replace a water heater and Lennox: when to replace a water heater.

Ruud water heater recalls

No Ruud water heater recalls were found in U.S. Consumer Product Safety Commission data when this page was checked (2026-09-29). A decoded result checks your model number live.

Questions

Is a Ruud water heater dated the same way as a Ruud air conditioner?
No. On Ruud heating and cooling equipment, the four digits after the plant letter are the week and then the year. Ruud water heaters built before 2012 start with the month and then the year (Rheem’s template 1209D01234 is December 2009), while newer ones, from 2012 as each plant switched over, use a plant letter followed by the week and year.
Does a model number starting with R mean the unit is a Rheem?
No. Ruud’s own spec sheets print “R - Ruud” on models such as the RA14AZ and R801C, and a Rheem/Ruud manual says “R = RHEEM/ RUUD (ALL TRADEBRANDS)”. A U at the start, as on the UA16AZ or U96V, is used only by Ruud.
How can I tell a Ruud water heater from a Rheem one by the model number?
On the Professional tank heaters, Rheem and Ruud share the base number and the suffix tells them apart: RU for Ruud (as in PROG50-38N RU60) and RH for Rheem. Ruud tankless models start with RUTG.
How can I tell how old my Ruud water heater is?
Find the serial number on the rating plate and enter it above. Ruud water heaters use the Rheem / Ruud water heaters serial format, which includes the manufacture date. For example, 1209D01234 was made in December 2009: On Rheem water heaters built before 2012, the serial starts with the month and then the year: "12" is December and "09" is 2009.
Where is the serial number on a Ruud water heater?
The rating label is on the side of the tank: near the gas control valve on gas models, or above the upper heating-element cover on electric models.
How long does a water heater usually last?
A typical service life is about 8–12 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 Rheem water heaters use the same serial format?
Yes. Ruud and Rheem 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.

Same serial format: Rheem water heater

Other Ruud equipment: furnace, air conditioner, heat pump, tankless water heater

Sources

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.