State age lookup

How to read a State water heater serial number

Type the serial number from the label and the decoder shows when your State water heater was made. Below that: every State format the decoder knows, and a real label from one of my inspections.

Accuracy is not guaranteed.

This decoder gives an estimate based on how brands have coded serial numbers in the past. Manufacturers change their formats, and a serial can be misread, so the results may be wrong. Use them as a starting point only. Confirm with the date printed on the plate or with the manufacturer.

Reading a State water heater serial number

State water heaters are made by A.O. Smith, and newer State serials read the same way. The first four digits are the year, then the week, so a serial that starts 2002 was made in week 2 of 2020. Newer serials run 13 digits. Older State serials start with letters, where a letter stands for the month, and those formats are below too.

Rating plate on a State gas water heater, serial number 2002117747446 outlined in red
State gas water heater plate from one of my inspections. The outlined serial reads as week 2 of 2020. No date is printed, but the 2017 standards year on the label fits.

The State label above has no printed build date, so the serial is the way to tell. The ANSI Z21.10.3-2017 standard printed on the same label fits a 2020 heater. State labels give the company address as Ashland City, TN.

State serial number formats

Each format below has a made-up example split into its parts, so you can match it to your own serial.

  1. 4 digits for the year and week, then a letter and 6 digits or 9 more digits (about 2008 and later)

    Example1714A123456: Year 17, Week 14, Unit number A123456.

    Reads as week 14 of 2017. Used from 2005 to today.

    • The first 2 digits are the year and the next 2 are the week. Newer serials are 13 digits long and start the same way. A letter in front, if there is one, is skipped.

  2. A month letter, 2 digits for the year, then 6 or 7 more characters (before about 2010)

    ExampleC04A123456: Month C, Year 04, Unit number A123456.

    Reads as March 2004. Used from 1970 to 2010.

    • The letter is the month (A is January, M is December, no I) and the 2 digits after it are the year.

  3. 2 letters, 2 digits for the year, then 7 or more characters (before about 2008)

    ExampleGD99A123456: Factory G, Month D, Year 99, Unit number A123456.

    Reads as April 1999. Used from 1975 to 2008.

    • The first letter is the factory. The second letter is the month (A is January, M is December, no I) and the 2 digits after it are the year.

Where to find the serial number on a State water heater

Look for a label marked Serial, Serial No. or S/N. The model number is usually right next to it, so check which one you're reading.

  • Gas or electric tank. A rating label on the side of the tank, usually at eye level or above the gas control. If the tank sits in a closet, it may face the wall; a phone camera held at an angle often reaches it.

These brands share at least one serial number format with State, so their serials read the same way.

Another brand? Use the water heater serial number decoder for all 18 brands.

Buying a home in the Portland area?

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