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A. O. Smith Water Heater Age by Serial Number
Enter the serial number from your A. O. Smith water heater's data plate to get its manufacture date, remaining life, warranty and recall status, and a repair-or-replace recommendation.
How to read an A. O. Smith serial number
We can decode serial numbers from A. O. Smith water heaters built 1976–2007 and 2011–2026. We can't decode units built in 2008–2010 yet.
2011–2026 format
The first two digits of the serial are the year (for example 17 = 2017) and the next two digits are the week of that year (01-53). For example, 1719106145074 was made in the 19th week of 2017.
1976–2007 format Corroborated
The serial starts with a letter for the month, then two digits for the year. For example, M07A009387 was made in December 2007. Month letters run A (January) through M (December), skipping I.
This format is confirmed by two or more independent references rather than an A. O. Smith document for this product line, so treat dates from it as likely rather than certain.
1992–2004 format Corroborated
The serial starts with a letter for the factory, then a letter for the month, then two digits for the year. For example, SK973804428S19 was made in October 1997. Month letters run A (January) through M (December), skipping I; dashes in the printed serial are ignored.
This format is confirmed by two or more independent references rather than an A. O. Smith document for this product line, so treat dates from it as likely rather than certain.
Worked examples
year month / week
| Serial | Built |
|---|---|
| 1719106145074 | May 2017 |
| ME980041362917 | May 1998 |
| M07A009387 | December 2007 |
| SK973804428S19 | October 1997 |
| MH920020943S44 | August 1992 |
| AF04A093001 | June 2004 |
How long does an A. O. Smith water heater last?
| Type | Typical life |
|---|---|
| Gas tank | 8–12 years |
| Electric tank | 10–14 years |
| Heat pump water heater | 10–14 years |
| Tankless | 15–20 years |
Ranges come from industry life-expectancy studies (NAHB/Bank of America, InterNACHI, DOE) and apply across brands. Your result adjusts for your state's climate and water hardness.
Is my A. O. Smith water heater still under warranty?
- Models with warranty code E, F or G have a 6-year tank warranty and a 6-year parts warranty. The code is shown on the data plate.
- Models with warranty code P, X or PX have a 10-year tank warranty and a 10-year parts warranty.
- Models with warranty code H, including ProLine Master gas and electric models, have an 8-year tank warranty and an 8-year parts warranty.
- Polaris high-efficiency gas models have a 10-year tank warranty and a 1-year parts warranty.
- Voltex hybrid heat pump models (HPTS and HPTU) have a 10-year warranty. The FPTU model has a 6-year warranty.
- ProLine XE condensing tankless models have a 15-year heat exchanger warranty and a 5-year parts warranty for home use.
Registering your water heater is optional and does not change your warranty rights. The warranty starts on the installation date, so keep your installation receipt; without it, the manufacture date is used.
A. O. Smith water heater recalls
- Certain 30 And 40 Gallon A.O. Smith LP And Natural Gas Water Heaters Voluntarily Recalled (1991)
- CPSC, A.O. Smith Announce Recall of Water Heaters (A. O. Smith, Reliance, Apollo, State, Maytag brands) (2005)
- A.O. Smith Recalls Gas Water Heaters Due to Fire and Carbon Monoxide Hazards (A. O. Smith and State brands) (2008)
- A.O. Smith Recalls John Wood Brand Oil-Fired Water Heaters Due to Fire and Burn Hazards (John Wood brand, oil-fired) (2015)
- A. O. Smith Recalls Ultra-Low NOx Water Heaters Due to Fire Hazard (American, A. O. Smith, Kenmore, Reliance, State, U.S. Craftsmaster, Whirlpool brands) (2018)
- A. O. Smith Recalls 30-Gallon Gas Water Heaters Due to Fire Hazard; Sold Exclusively at Lowe's (2018)
Recalls come from the U.S. Consumer Product Safety Commission. Decode your unit above to check whether its model and serial fall inside a recall.
Should you repair or replace it?
Once you decode your unit, we compare its age against its typical life, a typical major repair against the cost of replacing it, and, with your model and state, what a new unit would save on energy. A common rule of thumb: if a repair costs more than about 30–50% of a replacement and the unit is past mid-life, replacing usually wins.
Related brands
A. O. Smith belongs to the same company as State and American Water Heater. Serial formats are often, but not always, shared.
FAQ
How do I tell how old my A. O. Smith water heater is?
The manufacture date is encoded in the serial number on the unit's data plate. The first two digits of the serial are the year (for example 17 = 2017) and the next two digits are the week of that year (01-53). For example, 1719106145074 was made in the 19th week of 2017. The serial starts with a letter for the month, then two digits for the year. For example, M07A009387 was made in December 2007. Month letters run A (January) through M (December), skipping I. The serial starts with a letter for the factory, then a letter for the month, then two digits for the year. For example, SK973804428S19 was made in October 1997. Month letters run A (January) through M (December), skipping I; dashes in the printed serial are ignored. We can decode A. O. Smith water heaters built 1976–2007 and 2011–2026. We can't decode units built in 2008–2010 yet. Enter the serial above to decode it automatically.
How long does an A. O. Smith water heater last?
Typical lifespans: Gas tank 8–12 years; Electric tank 10–14 years; Heat pump water heater 10–14 years; Tankless 15–20 years. These ranges apply across brands. Maintenance, climate and water hardness move a unit toward one end.
How do I check my A. O. Smith warranty?
Registering your water heater is optional and does not change your warranty rights. The warranty starts on the installation date, so keep your installation receipt; without it, the manufacture date is used. A. O. Smith's warranty lookup: https://www.hotwater.com/support/warranty-verification.html Register a unit: https://www.hotwater.com/on/demandware.store/Sites-hotwater-Site/default/ProductRegistrationForm-Show
Has my A. O. Smith water heater been recalled?
The U.S. Consumer Product Safety Commission lists 6 recalls for A. O. Smith water heaters. Enter your model and serial above to check yours against each recall's scope.
Sources: A. O. Smith service, warranty and installation documentation; independent industry references for formats no A. O. Smith document covers; U.S. Consumer Product Safety Commission; DOE and ENERGY STAR; NAHB/Bank of America and InterNACHI life-expectancy studies. More about our sources.