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State Select Water Heater Age by Serial Number — Free Lookup

A.O. Smith

Also works for A.O. Smith-built labels: State, Reliance, American, Whirlpool, U.S. Craftmaster, Kenmore, GSW and John Wood.

Find Your State Water Heater's Age

State water heaters are made by A.O. Smith, which acquired State Industries in 2001. Every State unit built since then carries A.O. Smith's serial date coding, so the manufacture date is hiding in the first few digits of the serial number. Enter your serial in the free decoder above for an instant answer, or follow the guide below to read it yourself.

Where to Find the Serial Number

Check the rating plate (data plate) on the side of the tank — a silver or white sticker, usually in the upper half of the unit on gas and electric tank models. The serial number is printed right next to the model number. On State tankless and hybrid heat pump units, the plate is often on the side panel or behind the front cover.

Older stickers fade or get painted over. If yours is hard to read, photograph it with your phone and raise the contrast — you only need the first four digits.

How the State Serial Format Works

Because State units come off A.O. Smith production lines, the date code is year, then week, in the first four digits:

Worked example — 1914B000123:

  • 19 = 2019 (year)
  • 14 = week 14 (early April)
  • B and the remaining digits = factory and production sequence
  • Result: manufactured in week 14 of 2019

Watch for letter prefixes. Some serials start with letters or insert a letter inside the date block — these are factory or product-line codes, not part of the date. Skip leading letters and read the first four digits you find: AF04A093001 decodes to week 4 of 2004, and 1604J004619 decodes to week 4 of 2016.

Since the year is only two digits, 0414... could theoretically be 2004 or 2014. Compare the unit's condition and model number — and when in doubt, our decoder flags ambiguous cases instead of guessing.

Why the Age of Your State Water Heater Matters

  • Lifespan. Tank water heaters average 8–12 years. Past that, internal corrosion makes tank failure — and a flooded floor — far more likely.
  • Warranty. State tank warranties typically run 6 to 12 years from the manufacture date. Decoding the serial tells you whether a repair might still be covered.
  • Maintenance timing. Sediment flushing and anode rod replacement pay off most in a tank's middle years; the exact age helps you schedule them.
  • 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 verified against A.O. Smith's acquisition announcement for State Industries, and serial format details verified against the InterNACHI water heater dating chart and A.O. Smith's own production-date guidance.

Frequently asked questions

What is a State Select water heater?
State Select is the brand name State Industries prints on most of its residential water heaters — it is the label you will actually see on the rating plate. State Select units are built by A.O. Smith (which acquired State Industries in 2001) and use the same year-week serial date code as other State, Reliance, and American units.
Who makes State water heaters?
State water heaters are made by A.O. Smith. A.O. Smith acquired State Industries in 2001, and State units have been built in A.O. Smith factories ever since — alongside sister brands like Reliance, American, and U.S. Craftmaster.
Where is the serial number on a State water heater?
On the rating plate — a sticker on the side of the tank, usually in the upper half, next to the model number. On State tankless and heat pump models, the plate may be on the side panel or behind the front cover.
How do I read a State water heater serial number?
The first two digits are the year and the next two are the week of manufacture — the same format as A.O. Smith. For example, serial 1914B000123 means week 14 of 2019. If the serial starts with letters, skip them and read the first four digits as year and week.
My State heater is older than 2001. Does the same format apply?
State Industries used its own serial coding before the A.O. Smith acquisition, but in practice most pre-2001 State serials also lead with a year-then-week or year-then-month digit block. If the decoder result looks off, cross-check the unit against the model number and its apparent condition.
How long does a State water heater last?
Most State tank-style units last about 8–12 years. Flushing sediment regularly and replacing the anode rod on schedule can push a unit toward the longer end of that range.