How Old Is Your Apollo Water Heater?
Apollo was a private-label brand built by the A.O. Smith manufacturing family, so the serial number carries the same date code as State, Reliance, American, and U.S. Craftmaster units: the manufacture date is in the first digits of the serial. Enter your serial number in the free decoder above for an instant answer, or follow the guide below to read it yourself.
Where to Find the Serial Number
Look for the rating plate — a silver or white sticker on the side of the tank, usually in the upper half. It lists the model number, serial number, and capacity together. The date lives in the serial, not the model number. If the sticker has faded, photograph it and boost the contrast — you only need the first four digits.
How the Apollo Serial Format Works
The date code is year, then week, in the first four digits:
Worked example — 1214A003927:
12= 2012 (year)14= week 14 (early April)Aand the remaining digits = factory and production sequence- Result: manufactured in week 14 of 2012
Watch for letter prefixes. Some serials start with letters, or insert a letter inside the date block — these are factory codes, not part of the date. Skip leading letters and read the first four digits you find. For example, AC0815B004772 decodes to week 15 of 2008.
Because the year is two digits, a code like 04 could be 2004 or 2014 on a modern-style serial. Compare the unit's condition and model line — and when in doubt, our decoder lists every plausible year instead of guessing.
Why Your Apollo Water Heater's Age Matters
- Lifespan. Tank water heaters average 8–12 years of service. Past that, internal corrosion makes tank failure — and a flooded floor — far more likely.
- Warranty. Apollo tanks typically carried 6- or 12-year warranties counted from the manufacture date. Decoding the serial tells you whether a repair might still be covered.
- Replacement planning. A unit past 10 years is on borrowed time. Knowing the date lets you shop calmly instead of during an emergency.
Sources
Brand ownership and serial format verified against the InterNACHI water heater dating chart, which groups Apollo with the A.O. Smith production-line brands, and A.O. Smith's manufacturing-date guidance.