How old is my Whirlpool water heater?

By Dana Whitlock. Updated October 2026. Widely documented.

Your Whirlpool water heater was not built by Whirlpool. American Water Heater makes it, and the serial follows American's code, the first two digits for the year and the next two for the week. A serial starting 0620 means week 20 of 2006, mid-May.

The Whirlpool water heater website carries American Water Heater's copyright next to Whirlpool's. Neither company publishes a serial decoder, so this one is filed under Widely documented. Federal recalls and the parent company's recall statement describe the year-week rule, and inspector references agree.

Where to find the label on a Whirlpool water heater

Whirlpool water heaters carry a data plate on the front of the tank. It names the model, the serial and the energy ratings. Garages, basements and laundry closets tend to be poorly lit, so take a flashlight. Stand back from a gas unit's burner area and read the plate without opening the access door. On an electric unit, keep the element covers on.

How to read the code

Cut the serial into a four-digit date block and a tail. In the date block, the leading pair is a two-digit year and the trailing pair is a week from 01 to 53. Everything in the tail is production sequence. Example from an inspector forum: 0145113368. That is 01 for 2001 and 45 for the 45th week, early November 2001. It is tempting to read 01 as January and 45 as 1945, but no water heater on a working home lasts 60-plus years, and the week reading fits.

Real serials in this code

When the format changed

Because Whirlpool tanks come from American Water Heater's plants, their serials have followed American's year-week system throughout the brand's run. That system matches A.O. Smith's post-2008 code too, since American is part of A.O. Smith. There is no letter cycle to untangle, and two-digit years only repeat every century. The one real source of error is digit order. If a reading gives a month above 12 under a month-year assumption, that confirms you are looking at a week. For coverage questions, Whirlpool's water heater owner center links to warranty help that works from the serial.

Who makes Whirlpool

Whirlpool-branded water heaters carry Whirlpool's trademark but are built by American Water Heater, an A.O. Smith company. Code siblings that read identically are American and U.S. Craftmaster. Whirlpool-branded tanks were also part of a 2019 A.O. Smith recall of Ultra Low NOx gas units, defined by first four serial digits between 1115 and 1631, the same rule used for the other brands in that recall.

How sure is this?

Widely documented. Whirlpool doesn't publish this code; it comes from recall notices, service literature and inspector references. We tested the american water heater rules against 6 serials, 4 of them with a date known from a recall notice, a printed label date or the maker. None decoded to a wrong year; codes whose year mark repeats show every possible reading. Always confirm with Whirlpool's serial lookup before you spend money on the answer.

Quick notes

• Do not use a Whirlpool appliance (fridge or washer) serial chart for the water heater. The codes are unrelated.
• If you have the original receipt, compare the purchase date to the build week. A gap of a few months is normal.
• An Ultra Low NOx gas Whirlpool whose first four digits fall between 1115 and 1631 should be checked against the 2019 recall notice.
• A gas tank past DOE's average life of about 14.5 years is a candidate for replacement quotes rather than a big repair.