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Dating Water Heaters

The following list of brands are of water heaters commonly found in southeast Michigan. This list is not an all encompassing list, however, a contentious effort was made to provide the correct information to assist in determining the age of the water heater despite the numerous manufactures and the variations of dating codes.

First, when dating a water heater, first look at the data tag, the manufacturing date may be displayed on the data sticker.

Second, look for the serial number. Sometimes the date is hidden within the serial number. For example, C12 could indicate that the water heater was constructed in March of 2012. Also look at the serial number. If there are 4 numerals at the start of the serial number, the first two numbers could represent the year, the next two numerals could represent the month or the week of manufacture, or vice versa. Compare this information to the “ANSI” (American National Standards Institute) or “CSA” (Canadian Standards Association) code dates described in the following paragraph.

Third, if the date of manufacture is not immediately evident a little sleuthing around the label may reveal the date of manufacture. Look at the lower portions of the data sticker for the letters “ANSI” or “CSA”. The four digits after the referenced standard authority usually represent the code or standards to which the water heater was constructed. For example, the if the “ANSI-Z” year is 2006, the water heater was likely constructed during a six year window from 2007 through 2012.

Finally, if all else fails look for the brand and the serial number in the following paragraphs:

American (also Champion, Craftmaster, Ace, Tru-Test, Whirlpool, U.S.)

The first two digits in the serial number represent the year, the next two digits represent the week of manufacture. For example, “0732” indicated that the water heater was constructed in 2007 in the 32 week.

A. O. Smith

Prior to 2008, AO Smith used the second letter as the month code followed by 2-digits which represent the year. For example, F08 is the sixth month of 2008. (The letter “I” is skipped as it looks too much like a “1”.) After 2008, AO Smith used the first two digits in the serial number to represent the year followed by more numerals representing the week. For example, 0806 is the sixth week of 2008.

Bradford -White (also Lochinvar)

Year (first digit) Month (second digit)

A 1984 A 2004
B 1985 B 2005
C 1986 C 2006
D 1987 D 2007
E 1988 E 2008
F 1989 F 2009
G 1990 A January G 2010
H 1991 B February H 2011
J 1992 C March J 2012
K 1993 D April K 2013
L 1994 E May L 2014
M 1995 F June M 2015
N 1996 G July N 2016
P 1997 H August P 2017
S 1998 J September S 2018
T 1999 K October T 2019
W 2000 L November W 2020
X 2001 M December
Y 2002
Z 2003

Due to a computer error, there were some 0A models manufactured=1997

Rheem (Lowe’s, Ruud)

Rheem uses a 2-digit month followed by a 2-digit year. For example, 0608 represents the sixth month followed by the year. Or June of 2008.

State (Ace, Barnett, Kenmore, Richmond)

Before 2008, State used a code having the first letter representing the month and the next two digits representing the year. For 2008 and after, use A. O. Smith’s code. State was acquired by AO Smith and uses Smith’s code. The first two digits in the serial number are the year followed by two more for the week. For example, 0806 is the sixth week of 2008.