Four digits, two pieces of information
Read the first pair as the year and the second as a production week. A prefix of 9746 means week 46 of 1997, not month 46. A prefix of 1924 means week 24 of 2019. The month beside a week result is only approximate.
Energy Trust’s American chart and InterNACHI’s U.S. Craftmaster family chart agree on this year/week layout. The Honest Home Inspections chart also describes it. American-family tanks have appeared under several store brands, but the manufacturer and full serial on the rating plate are the useful identifiers.
A source conflict to be aware of
Building Intelligence Center’s American style-1 text says the second pair is a month, while its other style and the independent charts say week. We use the corroborated week rule and show that caveat in the result. If a readable manufacture date is printed on your tank, use it to resolve any mismatch.
American is not American Standard
This page is for American Water Heater. American Standard heating and cooling equipment belongs on the Trane / American Standard page. Similar brand words do not imply the same date code.
Common questions
Can I use a Whirlpool tank’s code here?
Many Whirlpool tanks use the American year/week system. The Whirlpool page provides examples for that badge. Always select the name on the rating plate.
Can I check a warranty with this date?
This estimates manufacture only. American offers a warranty verification service; installation and purchase records may matter separately.
Where is the serial?
Look for the rating plate on the tank jacket. Newer labels may include a QR code leading to the maker’s product information. Copy the serial field, not the product or model number.
Worked examples
| Serial | Style | How it reads | Made | Example from |
|---|---|---|---|---|
9746123456 | Year + production week | 97 = year ’97; 46 = week 46 of the year | Week 46 of 1997 (around November) | Constructed to show the rule |
1924115263020 | Year + production week | 19 = year ’19; 24 = week 24 of the year | Week 24 of 2019 (around June) | Building Intelligence Center |
Not affiliated with American. Brand names describe decoder compatibility. Manufacture date is not installation date.
Sources
- Energy Trust of Oregon: Serial Number Decoder: Water Heater (PDF)Used for: Year + production week.
- InterNACHI (International Association of Certified Home Inspectors): InterNACHI Water Heater Dating ChartUsed for: Year + production week.
- Honest Home Inspections, LLC (hosted by InspectAPedia): How to determine Water Heater and Furnace Age (PDF, last updated 2009-01-06)Used for: Year + production week.
- Building Intelligence Center: american water heater age