How To Tell Age Of Water Heater (Different Manufactures)

As the winter season arrives, homeowners are increasingly worried about the need for hot water and the cost of maintaining it. Water heaters are an amenity that everyone should have, especially in the cold months. It allows for warm meals and relaxing showers at a time when the cost of many things begins to rise.

To determine the age of your water heater, check the build date on the label. If this does not give you a clear indication, the serial number can be decoded to reveal the month and year it was manufactured. Water heaters should generally be replaced after 10 years, but this lifespan will vary between different brands. 

While water heaters can be expensive, you should know the positive long-term impact of a replacement. If a heater is left to age, its problems could cost hundreds or thousands of dollars to fix. To prevent that from happening, we will help you determine if your water heater needs replacing.

Why does it matter how old my water heater is?

Like any amenity, water heaters are affected by years of regular use. Several problems can arise from an old heater such as rusty water, mold growth, and small flooding. 

Old water heater

While rust is not an immediate danger to your health, it can affect the taste of your tap water or add bits of metal to your drink. Nearby water heater pipes may leak and cause mold growth in your walls, which can put your or your family’s health at risk. Lastly, a burst in your heater might cause dozens of gallons of water to flood your rooms.

How long does a water heater last?

The general lifespan of a water heater is 10 years, with some as low as 8 years after factoring in the amount of use. However, several types of heaters vary in the number of years before needing a replacement. These are the types of heaters that are most common in households today.

Most Common in HouseholdsLife Expectancy
Condensing Water6-10 Years
Heat Pump10-15 Years
Solar-Powered15-20 Years
Storage8-12 Years
Tankless 15-20 Years

While these are expected lifespans, it considers the amount of use and model. For example, condensing water heaters can last anywhere from five to fifteen years based on the model and manufacturer. 

These heaters can last a few years after their expected lifetimes with proper maintenance and upkeep. Be sure to check the model, manufacturer, and maintenance of your heater to ensure that you get the most of what you pay for.

Least Common in HouseholdsLife Expectancy
Electric10-15 Years
Gas 8-12 Years
Gas-Electric (Hybrid)15-20 Years
Point-of-Use10-15 Years

Like the previous water heaters, proper care will ensure that your appliance can last. You can use techniques such as removing excess pressure from your tank, draining sediment buildup, insulating pipes, and checking the anode rod that attracts minerals floating inside.

How can I determine the water heater’s age?

To determine the age of your water heater, the best option is always the simplest: the label. Some manufacturers make it easy by labeling the build date alongside the serial number while others incorporate the date with the serial number. 

Find the label and search for a numbered month and year for the build date. If there is no explicit date, look at the serial number and use the guide below to read it. Do not confuse the serial number with the product number, which identifies a batch of products rather than the individual product. 

How can I use the serial number to determine water heater age?

If the build date was not clearly written, the serial number will show it instead. It may appear as a code of letters and numbers, but this varies based on the manufacturer and brand. When identifying the serial number, first find the label with the manufacturer and brand of the water heater. 

While some brands have the same code layout, this does not mean it’s the same for all. If your heater has a letter in the serial number, then it would correspond to a month. If it has digits, then it might also correspond to the week of the year rather than the month.

Serial Number

It’s extremely important that you identify the manufacturer to correctly translate the serial number of your brand water heater. You wouldn’t want to guess that your appliance was made one year ago as opposed to ten. Below is a list of manufacturers with information on how to identify them. 

What are the most common water heater manufacturers and what are their codes?

The most common water heater manufacturers are American Water Heater, A.O. Smith, Bradford White, Lochinvar, Rheem, and State Industries. These companies each have their own code layouts and it’s difficult to understand if you do not normally check your water heaters. When decoding the numbers, use this key to translate letters:

Lettered Years – Excludes Letters I, O, Q
A — 2004B — 2005C — 2006D — 2007E — 2008F — 2009G — 2010H — 2011J — 2012K — 2013L — 2014M — 2015N — 2016P — 2017/ 1997S — 1998T — 1999W — 2000X — 2001Y — 2002Z — 2003
Lettered Months – Excludes Letter I
A – January G – July
B – FebruaryH – August
C – MarchJ – September
D – AprilK – October
E – MayL – November
F – JuneM – December
  1. American Water Heater

AWH has two styles that depend on the generation of products. For models after 2008, AWH heaters’ codes are numbered with the year and week of the year. The first 2 digits show the year while the 3rd and 4th digits show the week of that year. For example, 1514**** would mean the heater was built on the 15th week of 2014.

The second AWH style is for models before 2008. The difference is the use of letters as opposed to numbers. Starting from the 2nd digit will be a letter for each month followed by a 3rd and 4th digit as the year. For example, *H02**** would mean the heater was built in August 2002.

American Water Heater
American Water Heater
  1. A.O. Smith

Fortunately, A.O. Smith’s serial number style is the same as AWH. The first style applies to models after 2008 and the second style applies to models before 2008.

A.O. Smith
A.O. Smith
  1. Bradford White

Unlike the previous companies, Bradford White has a single brand with a single style. There is no generation of heaters. By utilizing letters that correlate to years and months, it is sure to keep the serial numbers short. Use the above-mentioned letters key to decode. For example, XA**** would mean the heater was built on January 2001.

Bradford White
Bradford White
  1. Lochinvar

Lochinvar’s style is the same as Bradford White. For example, HL**** would mean the heater was built in August 2014.

Image Credits:
  1. Rheem

Rheem’s code styles are numerous throughout its brands. With over a dozen names and five styles between each, the concept is the same for all. There are no letters, so you won’t have to worry about translating the key. 

Style 1Digits 1 and 2 are month, Digits 3 and 4 are the year 0912**** built in September 2012
Style 2Digits 2 and 3 are the week Digits 4 and 5 are the year *3311****built on the 33rd week of 2011
Style 3Digits 3 and 4 are the week, Digits 5 and 6 are the year **1498****built on the 14th week of 1998
Style 4Digits 5 and 6 are the month, Digits 7 and 8 are the year ****0709****built on July 2009
Style 5Digits 1 and 2 are the year, Digits 3 and 4 are the month (sets separated by a period) 10.05**** built on May 2010

5. State Industries

State Industries is spread throughout many brands, but with a lesser amount of styles to memorize. Utilize the Lettered Months Key for the 2nd and 3rd styles. 

Style 1Digits 1 and 2 are the year, Digits 3 and 4 are the week1123**** built on the 22nd week of 2011
Style 2Digit 1 is the month,Digits 2 and 3 are the yearJ07**** built on September 2007
Style 3Digit 2 is the month,Digits 3 and 4 are the yearE04**** built on May 2004

Is it dangerous to keep an old water heater?

It is very dangerous to keep an old water heater because of the potential to deal more damage to your home. While leaks lead to mold, it can also lead to an infestation of bacteria, bugs, bursts, and explosions due to growing cracks. The worst-case scenario is structural damage to your home due to erosion caused by these leaks.

If that doesn’t convince you to replace an old water heater, then the money spent to repair its damage will continue to build. As well as money spent, the damage spread to other parts of your home might also cause you to move. 

My old water heater still works. Should I replace it anyways?

If your old water heater still works past its expected lifespan, it should still be replaced. Water heater prices will continue to rise and it’s important you keep necessary household products up to date. As always, prices vary depending on the size, model, manufacture, and type of heater.

You may spend as little as $800 to $1,700 on water heaters depending on your lifestyle. While the national average is roughly $1,200 for a replacement, it also does not account for the price of installation. 

Labor costs can be anywhere from $150 to $450, but can fluctuate depending on where you are located. From the lowest to the highest range, you can expect to spend anything from $1,000 to $2,000 for replacement and installation services.

Regardless of the cost, you should watch for the problems that come with an old water heater. Constant noises would vibrate throughout the house, minor leaks need constant repairs, and not having hot water on demand are all things you need to consider. 

At best, the cost for continued repairs will be greater than if a new one was already in place. While it may continue to work, short-term problems will only cause long-term problems


If you’re an owner looking to replace your water heater for the first time, it might be overwhelming. All it takes is a simple understanding of years, months, and letters. Even if your heater is new, be sure to watch it when the years roll by.

While you may not give it 24/7 attention, you should at least know its age to prevent issues down the line. The damages can be irreparable and it’s best to prepare in advance. By doing so, you can spend a few dollars now to save many dollars later. 

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