American Water Heater Age Lookup
American Water Heater builds tank, gas, electric, and hybrid units, and each serial number hides the date it left the factory. Drop yours in to reveal the manufacture month, the age, and how much warranty may be left. No sign-up required.
Need a plumber?
Get free quotes from licensed local pros, no commitment required.
Share this tool with friends!
Know someone with an aging water heater? Send them a free check.
Finding Your American Serial Number
Check these four spots on your American water heater
Common Locations
What to Look For
- White or metallic manufacturer sticker
- Labeled "Serial No." or "S/N"
- Typically 8–12 characters long
- Usually near the model number
Can't find it? Try removing access panels or checking behind the temperature dial.
American Serial Number Examples
Don't worry if yours looks different - American has multiple formats and our system can decode most variations.
About American Water Heaters
American Water Heater Company took its present form in 1997, when the Mor-Flo brands were merged together, and it has been an A.O. Smith subsidiary since 2006. It builds in Johnson City, Tennessee, and it is the plant behind a long list of other badges: U.S. Craftmaster, Craftmaster, Envirotemp, the Lowe's Whirlpool line, and A.O. Smith Signature. Distribution is wholesale, to contractors rather than to shoppers.
The residential range is ProLine gas and electric tanks from 30 to 100 gallons, plus power vent models and larger commercial units. Construction is standard for the industry: vitreous enamel lining, magnesium anode, and a self diagnostic gas valve on newer gas models. Six years on the tank is the common warranty, and on many model numbers a 6 or a 10 in the leading digits is the coverage length rather than a size or series code.
One serial rule prevents most American dating errors. An all numeric American family serial is year and week, never year and month, so a serial starting 0912 is week 12 of 2009 and not December of that year. Some serials place a plant letter after the four date digits, and older American Appliance units put a plant letter first instead.
Where to find the serial
American Water Heater (sold under the American brand and as Polaris) puts the rating plate on the top portion of the tank. The serial number is in a black box near the top of the label and is labeled SER NO. Polaris condensing units have the label on the side panel instead.
What the serial actually looks like
Why the age is worth knowing
American residential tanks typically have 6 or 9 year tank warranties, while Polaris condensing units get 10 years and run much hotter and harder. After year 10, even Polaris units start showing combustion chamber wear and the secondary heat exchanger needs annual cleaning to maintain efficiency.
Quick answers for this brand
Is American Water Heater related to A.O. Smith?
Yes, American Water Heater Company was acquired by GSW in 2002, and GSW was acquired by A.O. Smith in 2006. The Johnson City, Tennessee plant still produces American branded tanks alongside U.S. Craftmaster, Envirotemp, and several house brands using the same serial format.
What is the Polaris water heater and how do I age it?
Polaris is American Water Heater's high-efficiency condensing residential unit with a stainless steel tank and submerged combustion chamber. The serial decodes with the standard YYWW format, but the rating plate is on the side cover panel rather than the top of the tank.
Where is American Water Heater sold?
American branded units are sold primarily through plumbing wholesalers, with some appearance at Menards and regional retailers. They're often the lower-cost option in the A.O. Smith family, but the tanks themselves come off the same lines as the more expensive A.O. Smith models.
Need a plumber?
Get free quotes from licensed local pros, no commitment required.
Share this tool with friends!
Know someone with an aging water heater? Send them a free check.