Marathon MR20120

The MR20120 has a tank capacity of 20 gallons and electrical requirement of 120 volts. Perfect for an office with a kitchenette or for temporary structures that need hot water but do not require the larger capacity of other Marathon models.

Marathon MR20120 Features:

  • Seamless, blow-molded, polybutene tank – impervious to rust and corrosion 
  • Multiple layers of filament wound fiberglass give the tank unmatched strength 
  • Polyurethane Envirofoam™ insulation helps reduce energy consumption 
  • The most energy efficient in its class 
  • Recessed drain valve is out of the way of brooms and scrubbers 
  • Tough molded polyethylene outer shell resists dents and scratches 
  • Bowl shaped bottom allows complete sediment draining 
  • High temperature polysulfone dip tubes 
  • All plastic tank eliminates the need for an anode rod 
  • Thermally fused element to protect tank against “dry-fire”; low watt, density for long life. 
  • Factory installed temperature and pressure relief valve 
  • Factory installed vacuum relief valve 
  • Inlet and outlet connections are 3/4″ NPT 
  • Water tight grommets keep out overhead moisture and condensation

Buy the Marathon MR20120 Online Today!



Capacity: 20 Gallons
Element Size: 2000 Watts (120 Volts) 
Tank Height: 34 1/2 Inches
Tank Diameter: 23 3/4 Inches 
Weight: 61 Lbs 
Standards: Meets or exceeds ANSI standards and is UL listed. 

Service Parts

Marathon offers a full line of service parts for their entire water heater line. The following service parts are available for this model: