The year of manufacture of your water heater may be listed on the data plate sticker on the side of the water heater, but it is more likely that the date is encoded in the serial number. It is usually the first two numbers or second two numbers in the series, but varies by company and some use a single letter to indicate the year. Click on the brand of your water heater below to go to a page with instructions on how to interpret that specific manufacturer's serial number, along with examples.

A.O. Smith  A.O. Smith tankless 
American  American ProLine  
Ariston  Bosch Bradford White 
Craftmaster  Eccotemp  EcoSmart  
Eemax  Envi-Ro-Temp   GE  GSW  
Intertherm Jackson  Jacuzzi  
John Wood  Kenmore  Insinkerator  
Marey    Maytag   Mor-Flo   Navien  
Noritz  Paloma  Premier Plus   
Reliance   Rheem Rheem tankless    
Richmond    Rinnai   Ruud  Seisco   
SioGreen  State Industries   
Stiebel Eltron  Takagi  Tempra  
Therm-a-flow Tiny Titan  Titan  
Thermalux   Triangle Tube  
US Craftmaster  Westinghouse  
Whirlpool

• • • • • • • • • • • • • • • • • • • • • • • • • • • •  

Can’t find your water heater in this list? 

There are less than a dozen major manufacturers of water heaters, but many sell under multiple brand names. More than a hundred names have been used and then abandoned over the years, and many of them are the same as the major retailers that sell them, such as Lowes or Ace. We can’t list them all here. But, if you look closely for the fine print on the data sticker, you are likely to find the actual manufacturer’s name to use to decode the serial number. Here’s an example below.

Still stuck? Go to our blog post How can I determine the age of a water heater if the serial number is missing or decoding it is impossible?

• • • • • • • • • • • • • • • • • • • • • 
Field Guide for Home Inspectors, a quick reference for finding the age of 154 brands of HVAC systems, water heaters, and electrical panels, plus 210 code standards for site-built and manufactured homes, and the life expectancy rating of 195 home components. Available at amazon.com for $19.95.
• • • • • • • • • • • • • • • • • • • • • •  

Here’s links to a collection of more blog posts about WATER HEATERS:

• What are the signs it's time to replace my water heater? 

• Can a Temperature and Pressure Relief (TPR or T&P) valve be mounted to discharge horizontally?

• Where are gas water heaters not allowed to be installed?  

• Is the minimum size water heater inlet pipe 1/2" or 3/4" according to the building code?

• Can you use a light switch for a water heater disconnect? 

• How can I tell if a water heater is HUD-approved for mobile/manufactured homes?

• Can you wire a 240-volt water heater with 120 volts? 

• Is it alright to have a shut-off valve on both the hot and cold water pipes at a water heater?  

• What is the minimum clearance to doors and windows for an outdoor tankless gas water heater? 

• What is required clearance for access and working space in front of an electric water heater? 

• Why is the water heater older than the house? 

• Does a water heater need a shut-off valve? 

• Why should a tankless water heater have an isolator/service valve kit installed?

• When was a gas water heater first required to be elevated 18 inches above a garage floor?  

• Can the temperature and pressure relief (TPR) valve discharge pipe for a mobile/manufactured home water heater terminate under the home? 

• What is the purpose of a thermostatic mixing valve above a water heater? 

• Does a tankless gas water heater still work with no electricity during a power outage?  

•  Why do water heaters have a sacrificial anode? 

• What is the difference between a manufactured/mobile home water heater and a regular water heater? 

• Does a tankless water heater require a pressure relief valve?

• When is a water heater drain pan required?

• Why is there water in my water heater drain pan?

• What does it mean when a water heater Temperature/Pressure Relief (TPR) discharge pipe is "trapped"? 

• Can I leave a gas water heater in place when remodeling a garage into a family room or bedroom? 

• Where do I find the water heater in a mobile home?

• Does a tankless water heater in an attic require a drain pan? 

• Does an electric water heater require a disconnect? 

• Is a catch pan and drain piping required for a replacement water heater?

• What is the difference between a single element and dual element electric water heater? 

• What is an FVIR water heater?

• What is a dielectric union?

• What's that powdery crust on the pipe connections at the water heater? 

• What are the most common installation mistakes with water heater replacement?

• Why is my water heater making strange (rumbling, gurgling, knocking or banging) noises? 

• What can I do to make my water heater last longer?

• How does a hydronic heating system work?

• What is the difference between a regular water heater and a direct vent water heater? 

• What is the difference between a regular water heater and a power vent water heater?

• What is backdrafting at a gas water heater? 

• How do I determine if a water heater is gas or electric?

• What does it mean when a gas appliance (water heater, furnace, or range) has been "red tagged"?  

• What's the valve with the flip-up handle on the water heater for?

• Why is an older water heater an insurance problem?

   Visit our WATER HEATERS page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.