Marathon Heavy Duty Water Heater

Rheem’s Marathon™ heavy duty water heaters are specifically designed for installation in harsh environments or where high temperature water is needed. 

Price:From: $1,601.54

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Rheem’s Marathon™ heavy duty water heaters are specifically designed for installation in harsh environments or where high temperature water is needed. The heavy duty model comes in 75, 85, and 105 gallon tank capacities. Each heavy duty model comes equipped with factory installed titanium elements for the maximum protection against extreme water conditions and provides superior corrosion resistance. Each Marathon water heater features a high efficiency design that is lightweight and durable.  Rheem Marathon water heaters are made of unique cross-fiber polybutene creating a stronger and higher quality electric water heater with much longer life expectancy than regular steel electric or gas water heaters. Marathon water heaters come factory equipped with one fused upper heating element to protect against dry firing and a lower titanium plated water heater element that provides greater protection against lime and sediment build-up compared to copper or steel elements used in standard electric water heaters. If you have questions about shipping, find our policy here.

Marathon™ heavy duty water heaters are best used for:

  • Restaurants
  • Agricultural Processing
  • Applications with harsh water conditions
  • Applications requiring extreme water temperatures

Energy Savings

Marathon™ water heaters are unmatched in their energy savings. Every Marathon™ water heater uses electric immersion elements which transfer 100% of their energy into heat for the water. Marathons also significantly reduce heat loss by filling the tank shell with Polyurethane Envirofoam™ insulation. This foam traps the heat inside the tank and keeps the water hotter for longer periods of time without power cycling the elements to re-heat the water.

Standard steel tank water heaters can loose up to 30 degrees of water temperature over a 24-hour period, causing extra energy to be used to keep the water hot. Rheem’s Marathon™ water heaters are designed to only loose 5 degrees of water temperature in that same period of time. Over the course of a year this can account for significant savings on electric bills.


Capacity: 75 Gallons 85 Gallons 105 Gallons
Element Size: 4500 Watts 3800 Watts 3800 Watts
Tank Height: 58.6″ 66.25″ 66.75″
Tank Diameter: 28.25″ 28.25″ 30.25″
Weight: 122 lbs 134 lbs 152 lbs
First Hour Rating: 78 91 104


  • Register your tank within 90 days to receive your lifetime warranty

All units come complete with factory installed temperature and pressure relief valve, replaceable brass drain valve, and vacuum relief valve. The connections for cold inlet and hot outlet are 3/4 inch NTP, and should be roughed in at 5 3/4 inches on center.

Additional information

Weight 152 lbs
Dimensions Select options for details

105 Gallon, 75 Gallon, 85 Gallon




85-105 Gal Spec Sheet
75 Gal Spec Sheet