How old is my Ruud Water Heaters tankless water heater?

Serial number age decoder for Ruud Water Heaters tankless water heaters: 3 format eras, the decode rule in plain English, transcribed tables, and the official lookup.

• Ruud Water Heaters tankless water heater serial numbers in the era not stated format encode the year as digits 3-4 of the numeric part (YY) and the month as digits 1-2 of the numeric part (source: building-center.org).
• Example: serial RU 0904B21710 decodes to September 2004.
• Ruud Water Heaters tankless water heater serial numbers in the era not stated format encode the year as digits 1-2 (20YY) and the month as digits 4-5 (source: building-center.org).
• Example: serial 05.05-000021 decodes to May 2005.
• Ruud Water Heaters tankless water heater serial numbers in the era not stated format encode the year as digits 3-4 (YY) and the month as digits 1-2 (MMYY prefix) (source: building-center.org).
• Example: serial 0804B10488 decodes to August 2004.
• Ruud Water Heaters's official lookup at ruud.com returns warranty / registration lookup.

Format eras

• era not stated VERIFIED
  AA ####A#####digits 3-4 of the numeric part (YY)
• era not stated VERIFIED
  ##.##-######digits 1-2 (20YY)
• era not stated VERIFIED
  ####A#####digits 3-4 (YY)

How to read the serial

era not stated formatVERIFIED

Shape AA ####A##### · example RU 0904B21710 / RHNG 0804P000036 / R 0804B10488 · confidence high

Year

digits 3-4 of the numeric part (YY)

Week or month

month = digits 1-2 of the numeric part

Plant

letter after the 4 date digits

Example: serial RU 0904B21710 decodes to September 2004.

Listed under Ruud water heaters in the source; Ruud Water Heaters is named in that format's family and the corporate link is an estimate, not a checked fact.

era not stated formatVERIFIED

Shape ##.##-###### · example 05.05-000021 · confidence high

Year

digits 1-2 (20YY)

Week or month

month = digits 4-5

Example: serial 05.05-000021 decodes to May 2005.

Listed under Ruud water heaters in the source; Ruud Water Heaters is named in that format's family and the corporate link is an estimate, not a checked fact.

era not stated formatVERIFIED

Shape ####A##### · example 0804B10488 · confidence high

Year

digits 3-4 (YY)

Week or month

month = digits 1-2 (MMYY prefix)

Plant

letter at position 5

Example: serial 0804B10488 decodes to August 2004.

Listed under Rheem in the source; Ruud Water Heaters is named in that format's family and the corporate link is an estimate, not a checked fact.

Where the data plate is on a tankless water heater

On the side or bottom of the wall-hung cabinet, or inside the front cover on the frame.

General guidance, not brand-specific: the owner's manual or the installer can point to the exact spot. See the data plate guide.

For scale only: the InterNACHI Standard Estimated Life Expectancy Chart for Homes lists Instant (on-demand) Water Heater at 10 years of expected service (nachi.org). That chart is a guideline, not a prediction for your unit.

What we could not confirm

• Ruud Water Heaters is treated as sharing Ruud water heaters's format because the source lists it in that family; the corporate relationship itself is an estimate.
• Ruud Water Heaters is treated as sharing Rheem's format because the source lists it in that family; the corporate relationship itself is an estimate.
• Rheem water heater formats with an R/RH/RHLN/RHNG/RU prefix on many plates. rheem.registermyunit.com/en-US/warranty/brand?brand=ruud is the likely lookup (ESTIMATE, from the Rheem pattern in warranty_lookups.json). Plates since ~2004 also print MFG. DATE.

Sources

• https://www.building-center.org/ruud-water-heater-age/
• https://www.building-center.org/richmond-water-heater-age/
• img: Ruud1-Water-Heater-Age.png, Ruud5-Water-Heater-Age.png
• img: Ruud6-Water-Heater-Age-1.png
• https://www.building-center.org/rheem/
• https://www.rheem.com/faq/official
• https://www.ruud.com/warranty/official

Ruud Water Heaters water heater Rheem Manufacturing family All tankless water heater brands Guides