Brands that use this code
- Rheem, Ruud and Richmond. Rheem’s serial bulletin is titled “How to Locate and Read Rheem/Ruud/Richmond Serial Numbers”. Richmond says its heaters “are manufactured by Rheem”.
- GE tank water heaters made from mid-1999 until about the end of 2016. No source gives the exact end date; GE groups these as made before January 2017. In 1999 Rheem agreed to make GE-brand water heaters sold at The Home Depot, the first time it made heaters for another company. GE’s support pages now split its heaters into “Water Heaters Made Before January 2017” and “Water Heaters Made July 2019 - Current”. Rheem-made GE serials often start with GE, GENG or GELN.
- Not covered: GE tanks made before mid-1999, GE heaters made from January 2017 on, and GE GeoSpring heat pump heaters. Use the date printed on their plates.
Basis: official (Rheem Technical Service Bulletin 1207, Richmond, GE Appliances support) and trade press (Supply House Times, June 1999).
Where the serial number is
The serial number is on the rating label on the outside of the heater. GE says to look on the side of the unit, right or left. Rheem’s newer rating label, introduced from April 2012 at its Mexicali plant and June 2012 at Nuevo Laredo, prints the date of manufacture on the third line.
Basis: official (GE Appliances; Rheem Technical Service Bulletin 1207).
Which format do you have?
Ignore any letters at the start that aren’t a single plant letter; they’re brand or fuel codes (R, RH, RN, RHLN, GE, GENG, GELN and so on).
| Serial looks like | Format | Example |
|---|---|---|
| One plant letter (A, W, Q, M or C) followed by 9 or more digits | Week and year (from 2012) | M141209135 |
| Four digits, then usually a letter, then more digits | Month and year (before 2012, and plants not yet switched) | RH 0806B17262 |
Basis: official (Rheem Technical Service Bulletin 1207). A week number can be 13 to 53; a month can’t, which settles most doubtful cases.
Month and year (before 2012)
Rheem’s page labels the first two digits as the month manufactured and the next two as the year manufactured, followed by a plant line code and a consecutive serial number:
| Serial | Month | Year | Built |
|---|---|---|---|
| 12 09 D 01234 (Rheem’s illustration) | 12 | 09 | December 2009 |
| RH 0806B17262 | 08 | 06 | August 2006 |
| RN 1292A29282 | 12 | 92 | December 1992 |
| GE 0408B3174 | 04 | 08 | April 2008 (matches the date printed on its plate) |
| GELN 0699121611 | 06 | 99 | June 1999 |
Basis: official (rheem.com); examples from Inspectapedia and ABI Home Services, as listed in the sources. InterNACHI’s chart gives the same rule (“1st & 2nd digit = month, 3rd & 4th digit = year”).
Week and year (from 2012)
Rheem’s Technical Service Bulletin 1207 gives the new layout as PWWYY00001: P is the plant identification code, WW the week and YY the year. The new rating label started at Mexicali on April 2, 2012 and at Nuevo Laredo on June 4, 2012; the bulletin says each plant “will migrate to the new serial number as they are migrated to Oracle”.
| Plant letter | Plant |
|---|---|
| A | Montgomery |
| W | Water Heater Innovations |
| Q | Nuevo Laredo, Mexico |
| M | Mexicali, Mexico |
| C | Canada |
| Serial | Plant | Week | Year | Built |
|---|---|---|---|---|
| M141209135 (Rheem’s example) | Mexicali | 14 | 2012 | early April 2012 |
| Q231299996 (Rheem’s example) | Nuevo Laredo | 23 | 2012 | early June 2012 |
| GE A511315388 | Montgomery | 51 | 2013 | December 2013 (its plate says 18 Dec 2013) |
Basis: official (Rheem Technical Service Bulletin 1207); the GE example is from Inspectapedia. A brand prefix can come before the plant letter, as in RHUN M181401735 (Mexicali, week 18 of 2014).
If you can’t read it
Ruud’s age calculator takes a serial number, and newer plates print the date. Very old serials that don’t fit either layout can’t be decoded by our checker.
Recalls to know about
We found four CPSC recalls that name Rheem, Ruud, Richmond or GE heaters (checked 30 September 2026):
| Recall | Brands and products | Hazard | How to tell if yours is affected |
|---|---|---|---|
| CPSC 16-177 (May 26, 2016) | Rheem Performance Platinum electric water heaters (40, 50 and 80 gallon), sold only at The Home Depot from January 2014 through April 2016. About 54,000 units | “The control panel on the water heaters can overheat, posing fire and burn hazards.” | Models XE40M12EC55U0 and XE50M12EC55U0: serials A0114XXXXX to A5214XXXXX, M0114XXXXX to M5214XXXXX, Q0114XXXXX to Q5214XXXXX, A0515XXXXX, and A1015XXXXX to A1615XXXXX. Models XE50T12EC55U0 and XE80T12EC55U0: the first three of those ranges only |
| CPSC 07-108 (Feb 21, 2007) | Indoor Power Vent 199,900 BTUH tankless gas water heaters sold as Rheem, Ruud, Rheem-Ruud, Richmond and Paloma, May 2004 through December 2006. About 42,200 units | Parts can shift in transit so that an air filter door switch doesn’t work properly; if the switch fails and the door is out of place, the heater can keep running and dust and lint can build up, “posing a carbon monoxide poisoning hazard.” | Rheem RTG-74PVN, RTG-74PVP, RTG-74PVN-1, RTG-74PVP-1; Ruud RUTG-74PVN, RUTG-74PVP, RUTG-74PVN-1, RUTG-74PVP-1; Rheem-Ruud GT-199PV-N, GT-199PV-P, GT-199PV-N-1, GT-199PV-P-1; Richmond RMTG-74PVN, RMTG-74PVP, RMTG-74PVN-1, RMTG-74PVP-1, RMTG-74PVNH, RMTG-74PVPH, RMTG-74PVNUH, RMTG-74PVPUH (Paloma models on the notice) |
| CPSC 05-274 (Sep 16, 2005) | Robertshaw R110 gas control valves on natural gas and LP water heaters of several brands, including Rheem, Ruud, Richmond, GE and Hotpoint. About 178,000 units, all brands | “Screws on some water heater valves could break. If this happens, gas could leak from the valve, which poses a risk of gas explosion and fire.” | Valves made July 25 to August 14, 2005, with production date codes 5-31 through 5-33, “although not all valves with these date codes are affected.” Electric heaters aren’t included, nor heaters sold or serviced before July 25, 2005 |
| CPSC 80-042 (Dec 4, 1980) | LP gas water heaters with White-Rodgers thermostats from several makers, sold between 1961 and 1980. Rheem brand names on the notice: Right, Right 10, Right Miser, Right Miser 10 and Montgomery Ward models 33032, 33158, 33166 and 33376. About 600,000 units, all makers | The thermostat’s safety valve could stick open and let LP gas escape: an explosion hazard | An LP gas heater sold under one of those names between 1961 and 1980 |
Basis: official (CPSC notices in the sources). For 16-177, CPSC says: “The water heaters have a rating plate near the bottom of the unit with the model number, date of manufacture and serial number.” Its serial ranges fit the plant letter, week and year layout above: A0515 reads as Montgomery, week 5 of 2015, and 30Jan2015 is among the manufacture dates CPSC lists (our reading). For 07-108, the model is on the rating plate, a silver label on the front in the lower right-hand corner.
GE: we found no CPSC recall of a GE-brand water heater itself; GE and Hotpoint are on the 05-274 valve list.
Old recalls may have closed, and the phone numbers and web addresses in them may no longer work. Confirm the exact models on the CPSC notice, and run your model through our recall check. CPSC’s 05-274 notice adds: “If you smell gas near the appliance or in the building, immediately leave the area and call your gas company or a certified gas technician to investigate the cause.”
What the age means
Rheem says tank water heaters typically last 8 to 12 years, and that “the risk of leaks and sudden failure increases significantly after 10 years.” Across published sources a tank typically lasts about 11 years (range 8 to 15); see how long water heaters last.
If yours is past 10 years, price a replacement before it fails: what a new water heater costs installed. Doing a whole-house check? How old is my AC or furnace reads Goodman, Carrier and Trane serials too.
Limitations
- Rheem’s current web page shows only the month-and-year format; its 2012 bulletin describes the newer week-and-year format. We follow the bulletin.
- Rheem hasn’t said when every plant switched formats, so a 2012–2014 serial may use either.
- Rheem tankless serials (for example 05.05-…) use another layout, and sources disagree on which pair is the year. Read the date on the plate.
Checked against the sources below on 30 September 2026.
