Who makes Rinnai water heaters
Rinnai America Corporation is based in Peachtree City, Georgia. CPSC’s 2025 Rinnai boiler recall lists it as the importer of units made in Japan, and Rinnai says it opened its first US plant in Griffin, Georgia in 2018 “to assemble tankless water heaters in the United States.” Its first North American unit, an RL tankless model, came off the line on April 23, 2018. Rinnai’s US range covers tankless water heaters, electric water heaters, boilers and direct vent heaters.
Basis: official (rinnai.us; CPSC recall 25-313).
Where the serial number is
Look for the rating label on the side of the unit. Parts Town says the serial is “on the rating data plate or you can find it on the manufacturer label attached to the unit”, typically on the side panel. The serial is the code shaped like NK.CA-129326 (or, on older units, 04.03-102521); the model number starts with letters such as RU (e.g. RU98i).
Basis: industry references (Parts Town, TanklessHelp). Don’t remove covers to find it; the label is on the outside.
How to read the date: letter code (about 2009 on)
Rinnai’s service manual: “The first letter indicates the year of manufacture and the second letter indicates the month of manufacture.” Its example, BH.AB-000123, is August 2010. The third and fourth letters aren’t part of the date; the manual says they indicate the manufacturing location and product type.
Year letters
| Letter | Year | Letter | Year | Letter | Year |
|---|---|---|---|---|---|
| A | 2009 | J | 2017 | S | 2024 |
| B | 2010 | K | 2018 | T | 2025 |
| C | 2011 | L | 2019 | W | 2026 |
| D | 2012 | M | 2020 | X | 2027 |
| E | 2013 | N | 2021 | Y | 2028 |
| F | 2014 | P | 2022 | Z | 2029 |
| G | 2015 | R | 2023 | ||
| H | 2016 |
Rinnai doesn’t use I, O, Q, U or V for years. Each letter means one year only (the table runs to 2029), so there is no decade to guess.
Month letters
| Letter | Month | Letter | Month |
|---|---|---|---|
| A | January | G | July |
| B | February | H | August |
| C | March | J | September |
| D | April | K | October |
| E | May | L | November |
| F | June | M | December |
Basis: official (Rinnai’s service manual, section “Serial Number Format”, headed “Water Heaters and Direct Vent Furnaces”; its text and the June 1, 2010 date refer to the furnaces). For water heaters, the same letters are used by Building Intelligence Center, Parts Town, TanklessHelp and DeMark Home, and Rinnai’s own April 2012 brochure lists tankless serials starting DB (February 2012) for units shipping from April 2012.
Older units: year and month in digits
Before the letters, Rinnai serials started with the year and month as numbers. The manual: “The first two numbers indicate the year and the next two numbers indicate the month”, with the example 03.06-001000 (June 2003). Some older units show the same four digits with no period, for example 05083453 (August 2005, per Parts Town). CPSC’s 2008 recall of Rinnai wall furnaces (not water heaters) describes the same layout: “the first four digits of the serial number, written as YY MM.”
Rinnai’s manual dates the switch to letters to June 1, 2010 for its direct vent furnaces. For water heaters, Building Intelligence Center says the letter style “has been used since 2009”; Rinnai hasn’t published an exact date. Because of that, the checker marks numeric-era readings as medium confidence. The date itself isn’t in doubt: the two formats can’t be confused.
Worked examples
| Serial | Reads | Built | Where the example comes from |
|---|---|---|---|
| BH.AB-000123 | B = 2010, H = August | August 2010 | Rinnai service manual (illustration) |
| NK.CA-129326 | N = 2021, K = October | October 2021 | TanklessHelp (stated) |
| CD.CA-061205 | C = 2011, D = April | April 2011 | DeMark Home (stated) |
| BL.CA-051306 | B = 2010, L = November | November 2010 | Parts Town (stated); Building Intelligence Center |
| DB.BA-006175 | D = 2012, B = February | February 2012 | Rinnai April 2012 brochure, RU98i (our reading) |
| 07.12-123810 | 07 = 2007, 12 = December | December 2007 | TanklessHelp (stated) |
| 04.03-102521 | 04 = 2004, 03 = March | March 2004 | Parts Town (stated) |
| 06074363 | 06 = 2006, 07 = July | July 2006 | DeMark Home (stated) |
Don’t read it with Bradford White’s chart
Rinnai’s letters look like Bradford White’s but mean different years. On a Rinnai, B is 2010; on Bradford White’s chart, B is 2005 or 2025 (1985 on the same cycle). Rinnai also uses R (2023), which Bradford White never uses for a year, and doesn’t use O at all: P is 2022. Bradford White’s own serials are two letters followed only by digits, so a four-letter serial like BL.CA-051306 isn’t in Bradford White’s format.
If you can’t read it
Call Rinnai Customer Care at 1-800-621-9419, Monday to Friday 8 am to 8 pm Eastern, with the full serial and model number. We found no public online age lookup.
Recalls to know about
We found no CPSC recall of a Rinnai water heater (checked 30 September 2026). We found two other Rinnai products recalled through CPSC, and both are on Rinnai’s recall page:
| Recall | What | How to tell |
|---|---|---|
| CPSC 25-313 (Jun 2025) | i-Series Plus wall-mounted gas boilers, including combi models IP175199C and IP199199C, which also heat water: “The boiler door can fail to seal properly due to incorrect screws, allowing carbon monoxide (CO) gases to escape.” About 2,030 units | Models IP175S, IP199S, IP175199C, IP199199C sold September 2024 to February 2025 |
| CPSC 08-199 (Feb 2008) | EnergySaver direct vent wall furnaces RHFE 431 and RHFE 556 (not water heaters): “A gasket in the unit can fail, posing a risk of poisonous carbon monoxide gas leaking into the home.” About 52,000 units | Made February 2000 through December 2007. CPSC: the date code is “the first four digits of the serial number, written as YY MM,” at the bottom of the rating plate |
Basis: official (CPSC notices; rinnai.us). Our recall check covers water heater notices, so check boiler and furnace models on the CPSC notices directly.
What the age means
Rinnai: “The life expectancy (or useful lifespan) of a Rinnai tankless water heater is up to 20 years. Actual life is impacted by water quality, usage and proper maintenance.” The US Department of Energy gives tankless heaters about 20 years: the figure in its Energy Saver guide (now archived) and in the analysis for its 2024 gas tankless rule, which was withdrawn in 2025. That is the figure the checker compares a Rinnai’s age with. More: how long do water heaters last?
Pricing a new Rinnai or another tankless model? Tankless water heater cost compares gas and electric units by state; the replacement estimator adds labor and extras.
Limitations
- Rinnai’s own statement of the letter code is in a service manual section headed “Water Heaters and Direct Vent Furnaces” whose text refers to the furnaces; for water heaters it is backed by industry references and serials in Rinnai’s 2012 brochure, which fit it.
- We haven’t seen a Rinnai water heater serial starting with A (2009), so we can’t confirm exactly when water heaters switched.
- Heat pump, electric and hybrid Rinnai models may use other formats; we found no documented examples. Read the date on the label or ask Rinnai.
- The serial gives the build month, not the install date.
Checked against the sources below on 30 September 2026; sources added or changed on 6 October 2026 were checked that day.
