How to read American water heaters serial numbers
This covers American, American Water Heater, U.S. Craftmaster. The serial number is on the rating plate on the side of the tank, which also shows the Johnson City, Tennessee address.
Reading it yourself
Ten digits. The first two are the year and the next two are the week of the year.
Example:
9950123040was made in week 50 of 1999.
This is the date the unit was made. It was usually installed soon after, but it can be later. If a serial doesn’t fit any of these patterns, look on the label for a printed manufacture date.
Sources
Checked in October 2026.
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