How old is my water heater?

Water Heater Updated: September 10, 2021

The lifetime of a water heater can range from eight to 20 years. Knowing how old your water heater is can help you plan for potential maintenance—or decide when it’s time to get a new one. The following tips from the Northwest Energy Efficiency Alliance can help you determine the age of your water heater and whether you should consider a replacement.

First up: Find your water heater

Water heaters are typically tucked away out of sight in the basement, attic, crawlspace, utility closet, laundry room or garage. The closer it is to your kitchen or bathroom, the faster the hot water can travel to those faucets.

Check the label

The manufacturer label on the side of your water heater should include the installation date. If the label is unavailable, try checking your water heater’s serial number. This should also be located on the side of the tank, usually somewhere near the warning labels and energy guide.

Make sense of the serial number

Each manufacturer has a different format for their serial number, so the way the installation date is displayed varies. Identify the manufacturer of your water heater and use the following guide to determine how old your water heater is.

American and AO Smith

2008–present: YYWW*******
- YY = Year of manufacture
- WW = Week of manufacture
  - Example: 19021234567 = 2019, second week (early January)

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: 7D081234567 = July 2008

Bradford White

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

Note: Bradford White water heaters manufactured 20 years apart will have the same letter designation.

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: WL6511396 = November 2000

Rheem and Ruud

MMYY****
- MM = Month of manufacture
- YY = Year of manufacture
  - Example: 0203D1234 = February 2003

When should I replace my water heater?

Now that you know how old your water heater is, you can determine whether it needs replacing. If your tank-style unit is 8–10 years old or your tankless unit is 15–18 years old, it may be time for an upgrade.

In addition, you may want to consider getting a new water heater if you experience any of these warning signs:

The water temperature drops.
The hot water is rusty or tinted.
The unit is making rumbling or banging sounds.
The tank is leaking.

Upgrading your current water heater with an energy-efficient model before it breaks down can help you avoid costly water damage, reduce your energy and maintenance costs, and save you the stress of dealing with an emergency replacement.