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Water Heater Age

Updated: Dec 5, 2022

Often if agents look at the serial plate of main systems, and don't see the age clearly labeled on them, they will leave it to home inspectors to determine. That's not necessary, as you'll see below with a quick reference guide to some of the most common water heaters and a link to more water heater information. For brevity & what's most important, I'm only focusing on the year of manufacture. See the hyperlinks for additional details on the week/month/other information.

Disclosure on Limited Accuracy

Sources are hyperlinked on each row. For a more comprehensive list, go to's list here. I found their lists to be more accurate/user-friendly than others, though you'll have to do more digging than the guide below since they don't publish a quick reference chart like this one.


which serial #s for age (focus on year; "numerical digits" excludes alphabetical)

Style Patterns (yr in blue)

Lettering system (if applicable to yr)

1st 2 yr

Style 1: 05035 35368 Style 2: 1924115263020

1st 2 numerical digits = yr

Style 1a: 1210A002243

Style 1b: S1318 F000046

Style 1c: 1836111786352

Style 2: AF04A093001

Style 3: GG03-1495366-S29

Style 4: E07A135491



A: 1984 or 2004

B. 1985 or 2005

C. 1986 or 2006

D. 1987 or 2007

E. 1988 or 2008

F. 1989 or 2009

G. 1990 or 2010

H. 1991 or 2011

J. 1992 or 2012

K. 1993 or 2013

L. 1994 or 2014

M. 1995 or 2015

N. 1996 or 2016

OA. 1997

P. 1997 or 2017

S. 1998 or 2018

T. 1999 or 2019

W. 2000 or 2020

X. 2001 or 2021

Y. 2002 or 2022

Z. 2003 or 2023