Water Heater Brands
We decode serial numbers for 35 water heater brands, grouped below by manufacturer family. Click any brand for the age calculator, serial format guide, and brand-specific FAQs.
A.O. Smith family
Brands manufactured by A.O. Smith Corporation, North America's largest water heater maker. All share the same YYWW serial date code in the first four digits.
- A.O. Smith
A.O.
- State
State residential tanks typically come with 6, 9, or 12 year tank warranties.
- American
American residential tanks typically have 6 or 9 year tank warranties, while Polaris condensing units get 10 years and run much hotter and harder.
- Kenmore
Kenmore as a brand effectively ended for water heaters after Sears began closing stores in 2018.
- Reliance
Reliance residential tanks carry 6, 9, or 12-year tank warranties depending on the line.
- Whirlpool
Whirlpool stopped selling water heaters at Lowe's in 2017, but units installed during that decade are now hitting the end of their typical 8 to 12 year service life.
- Envirotemp
Envirotemp is a value-tier brand with typical 6-year tank warranties.
- U.S. Craftmaster
U.S.
- Mor-Flo
Any Mor-Flo branded tank in service today is at least 25+ years old since new production ended in the late 1990s.
- American Standard
American Standard water heaters typically carry 6 or 9-year tank warranties depending on the line.
- Maytag
Maytag residential tanks typically carried 6 to 12 year warranties depending on the model, and the warranty clock runs from the manufacture date on the label, not the install date.
Rheem family
Brands manufactured by Rheem Manufacturing Company, including the discontinued GE and Hotpoint lines that were built under contract through 2016.
- Rheem
Rheem residential warranties run 6, 8, 10, or 12 years depending on the model, and the clock starts at the manufacturing date on the sticker, not the install date.
- Ruud
Ruud is positioned as the upmarket Rheem brand, and most residential Ruud tanks carry 6 to 12 year tank warranties.
- Richmond
Richmond residential tanks come with 6, 8, or 10-year tank warranties depending on the line.
- Paloma
Paloma tankless units carry warranties similar to Rheem (12-year heat exchanger on most condensing models, 5 years on parts).
- Vanguard
Vanguard tanks were positioned as a value brand within the Rheem family and most carry 6-year tank warranties.
- Marathon
Marathon has a lifetime tank warranty (the tank itself cannot rust because it's plastic), so age is really about the heating elements, thermostats, and the foam insulation degrading.
- General Electric (GE)
Any GE water heater in service today is approaching or past its expected 10-12 year service life since GE exited the category in 2016.
- Hotpoint
Hotpoint water heaters were discontinued along with the broader GE exit from the water heater business in 2016.
Tankless specialists
Manufacturers focused on tankless and combi water heating. These units use brand-specific date encodings rather than the standard tank-style WWYY or YYWW formats.
- Rinnai
Rinnai backs residential tankless units with 12-year heat exchanger warranties (15 on Sensei SE+ condensing models), 5 years on parts, and 1 year on labor when professionally installed.
- Navien
Navien NPE-A and NPE-S series carry 15-year heat exchanger warranties and 5 years on parts when professionally installed, which is class-leading.
- Noritz
Noritz condensing residential tankless (NRC series) carry a 12-year heat exchanger warranty, while the EZ direct-tank-replacement series carries an extended 25-year heat exchanger warranty -- both are condensing units.
- Takagi
Takagi residential tankless units come with 15-year heat exchanger warranties on the T-H3 condensing models and 10 to 12 years on non-condensing T-K series.
- Bosch
Bosch tankless units carry 10 to 15 year heat exchanger warranties depending on the model and 5 years on parts.
Electric tankless
Point-of-use and whole-house electric tankless brands. These units do not encode the manufacture date in the serial number - the date is printed on the rating label instead.
- EcoSmart
EcoSmart electric tankless units carry a limited lifetime residential warranty on the exchanger, electronics, and elements when registered, subject to conditions, so the purchase date matters for coverage.
- Titan
Titan SCR-controlled electric tankless heaters are known for simple, long-lived designs with serviceable parts.
Independent and specialty
Independent manufacturers who sell primarily through plumbing wholesalers rather than big-box retailers, plus commercial specialty brands.
- Bradford White
Bradford White builds heavy-duty tanks and many residential units carry a 6-year tank warranty, while their Defender Safety System eF series commercial units can run 3 or 5 years.
- Jetglas
Because Jetglas tanks are rebadged Bradford White units, they share Bradford White's build quality and typically carry a 6-year tank warranty, with some lines running longer.
- Bock
Bock builds for commercial duty with heavy-gauge steel tanks and oversized heat exchangers, so a properly maintained Bock can run 20 or more years.
- Vaughn
Vaughn tanks (especially the Fury and Sepco indirect lines) are heavy-duty stainless or stone-lined units with expected service lives of 20+ years when properly maintained.
- Lochinvar
Lochinvar residential gas units typically carry around a 6-year tank warranty, while commercial units vary and many run far longer in service.
Canadian brands
Brands manufactured in Canada and sold primarily through Canadian retailers. Giant uses a separate date stamp rather than encoding the date in the serial.
Don't see your brand?
Many less common water heaters are private-label units made by one of the manufacturers above. Try our main checker and we'll attempt to identify the actual manufacturer from your model number, or upload a photo of the rating plate and our AI scanner will read it.
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