Ruud Water Heater Age
Ruud tanks come off the same lines as Rheem, so the serial uses the same code. Skip the letters at the start and the next four digits are usually the month and year. Enter yours below.
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Serial number age lookup
Where to find the serial number on a Ruud tank
Ruud’s rating label sits on the tank jacket: on gas models above the gas control valve, on electric models between the two element access covers. The serial is on the line marked Serial No., below the model number. Ruud model numbers often begin with P (for Professional) followed by fuel and size codes; they describe the tank, not the date.
Read the bottom of the label for a printed MFG. DATE before you decode anything. Many Ruud labels from the mid-2000s on include one.
How the Ruud date code works
Because Ruud tanks are built by Rheem, the serial follows Rheem’s water heater code:
- Letters first: one to four letters identifying the product line or plant. Skip them.
- Then the month and year: two digits each.
RU0712B12345is July 2012. - Or the week and year on some newer tanks:
B231912345is week 23 of 2019, which is early June.
- Month
- Year
- Not part of the date
- Month
- Year
- Not part of the date
- Week
- Year
- Not part of the date
Worked examples
| Serial | Built | Format |
|---|---|---|
| 0517C12345 | May 2017 | Month (2 digits) + year (2 digits) + plant letter + 5 digits |
| RU0712B12345 | July 2012 | Letter prefix + month (2 digits) + year (2 digits) |
| RHLN1105A54321 | November 2005 | Letter prefix + month (2 digits) + year (2 digits) |
| Q0418123456 | April 2018 | Letter prefix + month (2 digits) + year (2 digits) |
| B231912345 | June 2019 (week 23) | Letter prefix + week (2 digits) + year (2 digits) |
Example serials are made up to show the format; they don't belong to real units.
When four digits could be read either way, for example 0418 (April 2018 as a month, late January 2018 as a week), the two dates are only a few months apart, and the age barely changes.
A brand with a long history in water heating
Ruud is one of the oldest names in American water heating. Edwin Ruud, a Norwegian-born engineer working in Pittsburgh, developed one of the first automatic storage water heaters in the late 1800s, and the Ruud company built water heaters for decades before Rheem bought it in 1959. Today the Ruud name is mainly sold through plumbing and HVAC wholesalers and installed by contractors, while Rheem is the more retail-facing brand. In practice, a Ruud tank and the matching Rheem tank are close to identical underneath.
How long Ruud water heaters last
| Type | Typical life |
|---|---|
| Gas tank | 8–12 years |
| Electric tank | 10–15 years |
| Heat pump (hybrid) tank | 10–15 years (tank), compressor serviceable |
Ruud’s professional lines often come with longer tank warranties than entry-level retail models, which usually reflects extra anode protection and, sometimes, a heavier tank. That helps in hard water, but it doesn’t make the tank immune to corrosion.
What to check on an aging Ruud
- Anode rod: if it’s never been changed, a tank past 6 years almost certainly needs one, provided the tank isn’t already leaking.
- Relief valve: test it yearly. A valve that won’t reseat, or drips constantly, should be replaced.
- Drain valve: older plastic drain valves can crack or seep. A brass replacement is a cheap fix.
- Bottom of the tank: rust, white crust or dampness under the jacket means the tank is near the end.
What to do with your result
Under 6 years: look up the warranty. Contractor-installed Ruud tanks often carry 6 to 12-year tank coverage, and the installer may handle the claim.
6 to 10 years: service it. Flush it, check the anode and test the relief valve. Replace parts as needed, but start a replacement fund.
Over 10 years: get quotes. If the tank is in a spot where a leak would cause damage, replace it proactively.
Ruud also makes furnaces, air conditioners and heat pumps, and those use a different serial code. See the Rheem and Ruud HVAC decoder.
Frequently asked questions
How do I read a Ruud water heater serial number?
Skip the letters at the beginning. On most Ruud tanks the next two digits are the month and the two after that are the year, so RU0712… was built in July 2012. Some newer serials use the week instead of the month; the tool handles both.
Is Ruud the same as Rheem?
Ruud and Rheem are sister brands of the same company. Their water heaters are built in the same plants and share designs, with different branding and distribution, mostly through plumbing wholesalers for Ruud.
How long does a Ruud water heater last?
Around 8 to 12 years for a gas or electric tank, depending on water quality and maintenance.
Where can I buy parts for an old Ruud water heater?
Because Ruud and Rheem share components, Rheem parts with the same specification usually fit. A plumbing supply house can match parts from the model number.
Sources and accuracy
The Rheem / Ruud / Richmond water heaters decoder is built from these references and cross-checked between them. Facts are restated in our own words; any mistakes are ours.
- Rheem: how to locate and read your water heating serial numbers
- InspectAPedia: Rheem water heater age decoder
- Building Intelligence Center: Rheem water heater age
Status: being verified against real data plates. Rules last reviewed 2026-10-18; page updated 2026-10-26. Not affiliated with Rheem / Ruud / Richmond water heaters. Report a wrong result.
Part of the water heater age lookup
This page covers one brand. For all water heater brands, go to the water heater age lookup.