Marathon Electric Water Heater Review

Check out how Marathon electric water heaters, with their innovative engineering, high-efficiency operation, and long-lasting design, are the perfect solution for all your residential water heating needs. Find out what makes them different from other electric hot water heaters.



Marathon water heater

Superior design is what makes Rheem Marathon hot water heaters one of the toughest on the market. The tank is not made of metal as most of today's heaters, but from seamless blow-molded polybutene that makes it lightweight and rust-free, while the tank's concave bottom allows complete draining and easy sediments removal. 

The non-metallic design eliminates the need for the anode rod, its maintenance, service, and development of the rotten egg odor. The filament wound fiberglass allows the tank more flexibility and to withstand higher pressure than conventional electric heaters.

The water heater is enclosed in a rugged polyethylene jacket that resists damage and rust.

Dip tube

The dip tube can withstand higher temperatures, and a unique design allows the turbulent water flow, which reduces the sediment build-up problem.

Heating elements

Heating elements are of low-watt density, which allows greater performance and longer life. The thermally fused upper heating element protects from dry-firing, while the titanium lower element on some models prevents the limescale build-up.

When buying a Marathon electric water heater, let's say 50-gallon, you have an option to buy one of the three different models, which use 3000-, 3800- and 4500-watt heating elements. The heater with the strongest component will provide a better recovery rate but will need a stronger fuse.

Models and sizes

You can buy a Marathon water heater in sizes from 15 to 105 gallons, where the most popular size of 50 gallons is available as the tall and short model, and all models have an energy efficiency of over 90%.

Water heaters with the capacities of 15 and 20 gallons are designed for point-of-use service and one fixture, which makes them ideal for the distant sinks, condos, cottages, apartments... 

Models with 85 and 105-gallon tanks are built for heavy-duty use and have a 10-year warranty.

For storing hot water in the solar, geothermal, or indirect water heating systems, Marathon thermal storage tanks are the ideal solution and are offered in sizes from 50-gal to 105 gallons.


One of the main advantages of the Marathon electric water heater is the lifetime warranty on the tank, and, as advertised, you won't need another water heater in your lifetime. Thanks to the plastic design, the heaters are lightweight, easy to move and install. This is what makes a heater environment-friendly, so you won't need to dispose of it after 10 years or so.

Due to the bowl-shaped bottom and with the drain valve installed at its very bottom, it is possible to have a complete tank drain which is excellent if you have sediment and limescale build-up.

The foam insulation is very thick, 2.5 inches, and since the heat loss is only 5 F in 24 hours, this is what makes Marathon great at thermal energy storage.

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Marathon electric water heater is built in the USA, and Rheem owns the brand. It provides superior performance, quality, and reliability over other models. They can be used as the electric water heater or hot water storage when used with heat pumps, solar and geothermal heating.


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