TankBirthday

Montgomery Ward Water Heater Age: How to Decode the Serial Number

Rheem

Enter the serial number from the rating plate (the silver data sticker on the upper side of the tank; on tankless units it is inside the cover on the right side). Works for Rheem, Ruud and Richmond — many Rheem plates also print the manufacture date directly as "MFG. DATE".

How Old Is Your Montgomery Ward Water Heater?

Like Sears, Montgomery Ward never manufactured water heaters. Wards was a retailer — it bought tanks from established manufacturers and sold them under its own name, including the long-running Wards Signature line (Signature 300, 500, and 700 models). More than one company held that contract over the years, so identifying the maker is step one.

Who Actually Made Your Wards Water Heater

According to inspection-industry references, Montgomery Ward water heaters were built mainly by Rheem (alongside its Ruud and Richmond brands) and by State Industries, and some were sold under the Reliance name as well. The exact year ranges for each supplier are not publicly documented, so the reliable way to identify your unit's maker is the serial number format.

How to Tell: Serial Format Differences

Check the first characters of your serial against these documented patterns:

  • Rheem style — digits, often after an SN or SNN prefix, with the month and year in the first four digits. Example: SNN 0483113079 reads as April (04) of 1983, and 1170 3310 reads as November 1970.
  • Wards prefixed style — serials printed like SNN 1280A12345: ignoring the prefix, digits 1–2 are the month and digits 3–4 the year, so this one is December 1980.
  • State style — about 8 characters starting with a letter for the month (A = January, skipping I) followed by two digits for the year. Example: B9912345 is February 1999.

Try This Decoder First

Because most Wards tanks were Rheem-built, start with the decoder above. If it can not make sense of your serial — especially if it is short and opens with a letter followed by two plausible year digits — your unit is probably State-built, so try our A.O. Smith serial number decoder next (State became part of A.O. Smith).

Where to Find the Rating Plate

Look for the rating plate (data plate) on the side of the tank — a sticker, usually in the upper half, listing the model and serial numbers together. Wards model numbers often start with prefixes like SRM, SHL, or SHT. On very old units, also check the top of the tank and behind the front service panel.

Why the Age Matters

  • Lifespan. Tank water heaters average 8–12 years. Since no Wards unit has been made in decades, yours is far past that window.
  • Failure risk. Internal corrosion makes tank rupture and a flooded floor much more likely in an aging unit.
  • Replacement planning. Any Montgomery Ward water heater still running is on borrowed time — replace it on your schedule, not during an emergency.

Sources

Manufacturer history and serial formats verified against the InspectApedia Montgomery Ward water heater age decoder and the InterNACHI water heater dating chart. Rheem-built brand list per the Honest Home Inspections water heater age chart.

TankBirthday is an independent reference tool. It is not affiliated with, endorsed by, or sponsored by Rheem, A.O. Smith, Bradford White, or any other manufacturer. All trademarks are the property of their respective owners.

Water heater age estimates are provided for guidance only — always verify against the manufacturer's documentation or a licensed plumber before making repair or replacement decisions.