Whether you’ve recently moved into a new house or have simply forgotten the age of your current unit, figuring out how old a residential water heaters are can be tricky. Depending on the type of fuel and model, the lifetime of water heaters can be anywhere between 10 to 20 years.
You should be aware of the year of manufacture of the water heater installed so that you know roughly when to start looking for a replacement.
Preparing for the inevitable end of its lifespan will save you a headache down the road; when the water heater repairs start to stack up, it’s good to know if it’s worth the maintenance, or if you’d be better off with a new water heater. And when a water heater fails, it can be inconvenient or downright catastrophic.
Types of Water Heater Serial Codes
The first step to determine age of hot water heater is to check for a manufacturer label on the water heater’s tank (or on the side of tankless water heaters), which should include the installation date.
If you can’t find the installation date, the water heater serial number can be used to determine the age of your unit. The formats vary by manufacturer, so check which brand of water heater you have and reference it with the information below.
Bradford White
Bradford White water heaters manufactured 20 years apart will have the same letter designation in their serial numbers. The first letter of the serial number is the year, and the second letter is the month.
YM*******
Y = Year of manufacture
| 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 |
| P | 1997 or 2017 |
| S | 1998 or 2018 |
| T | 1999 or 2019 |
| W | 2000 |
| X | 2001 |
| Y | 2002 |
| Z | 2003 |
M = Month of manufacture
| A | January |
| B | February |
| C | March |
| D | April |
| E | May |
| F | June |
| G | July |
| H | August |
| J | September |
| K | October |
| L | November |
| M | December |
Example: WG6511396 = July 2000
Need a new Bradford White water heater installed?
Navien
Navien water heaters might have several formats of serial number, but they will all contain at least the year of manufacture.
Style 1: *****YYMDD*****
Style 2: *****YY********
Style 3: ****-YYYYMMDD-****
Style 4: ****-YYYY–MDD-****
Y = Year of manufacture
M = Month of manufacture
D = Day of manufacture
Need a new Navien tankless water heater installed?
Rinnai
A Rinnai water heater has a simple Year/Month format of serial numbers. The first two letters are the year, and the second two letters are the month.
YYMM*******
YY = Year of manufacture
MM = Month of manufacture
Example: 18031234567 = March 2018
Need a new Rinnai tankless water heater installed?
Rheem
Rheem water heaters have a similar format to Rinnai, just in reverse; the first two letters of the serial number are the month of manufacture, and the second two letters are the year.
MMYY****
MM = Month of manufacture
YY = Year of manufacture
Example: 1114D1234 = November 2014
Need a new Rheem water heater installed?
A.O. Smith
A.O. Smith water heaters have two different formats of serial number, depending on the year it was manufactured.
2008-present:
YYWW*******
YY = Year of manufacture
WW = Week of manufacture
Example: 15051234567 = the 5th week of 2015 (early February)
Pre-2008:
*MYY******
M = Month of manufacture
| A | January |
| B | February |
| C | March |
| D | April |
| E | May |
| F | June |
| G | July |
| H | August |
| J | September |
| K | October |
| L | November |
| M | December |
YY = Year of manufacture
Example: 4D051234567 = April 2015
Need a new A.O. Smith water heater installed?
Can’t Find the Age of Your Water Heater?
If you’re having trouble finding the serial number or manufacture date on your water heater, one of our friendly technicians will be able to help you out.
Is it Time for a New Hot Water Heater?
If you’ve found your water heater’s serial number and have determined that it’s on its last legs, reach out to us. We can offer guidance on buying a new hot water heater, and provide quotes for whatever brand you decide to purchase or rent. Our team provides professional installation and replacement services, as well as rentals and repairs on several fantastic hot water heater brands.