On average a water heater will last you 8-12 years before needing replacement. If you were not the first owner of your home and are unsure when your hot water heater was installed it is important for you to find out this information. The good news is that this information is readily available and easy to find on your hot water heater itself. This guide will offer you step by step information to help you determine the age of your water heater and help you decide when it may be time to obtain a replacement.

Decoding serial numbers

The best way to determine how old your water heater is, is to look at the serial number. All water heaters will have a serial number located on the exterior of the unit. This applies to both hot water heater tanks and tankless water heater systems. Most serial numbers will be a combination of numbers and letters.

Some water heater manufactures, such as Rheem make it easy for you to determine the age of your water heater unit. On Rheem units, the serial number contains the year and month that the water heater unit was manufactured. By looking at the 9 digit serial code of a Rheem water heater you can note that the first four numbers of the serial number are the manufacture date.
An example of a Rheem serial code format could be as follows;

0108A1289

In this case the first two numbers, 01, are the month of manufacture while the second two numbers represent the year, 98. In this scenario the water heater would have been manufactured in January of 2008.

Types of Serial Codes

Not every water heater manufacture provides the date in such an clear pattern as Rheem. Listed below are a few examples of common water heater manufacturers and how they list their serial numbers and where you can find serial number information.

Navien – depending on the model of water heater you will see a different style of serial code. Navien provides a chart to help you decode your serial number.

Rinnai – similar to the example above the date of manufacture can be fpund in the first four numbers of the serial code. The first two numbers are the year and are then followed by the month.

What if I still can’t find it?

If you are having difficulty finding your water heater serial number it may be helpful to . A technician will be able to help you locate the serial number on your water heater unit and will also be able to help you determine your water heaters manufacture date.

Don’t forget maintenance

Always remember that regular maintenance will help to keep your water heating running for as long as possible. See our previous blog post for information on water heater maintenance and learn how to keep the water in your home hot while also helping to extend the life of your water heater for years to come.