Marathon non-metallic electric water heaters are durable, lightweight, and warranted not to leak as long as you own your home

Non-metallic Tank Features:

  • Seamless, blow-molded, polybutene tank – impervious to rust and corrosion
  • Multiple layers of filament wound fiberglass give the tank unmatched strength
  • Polyurethane insulation helps reduce energy consumption
  • Recessed drain valve is out of the way brooms and scrubbers
  • High temperature polysulfone dip tube
  • Tough molded polyethylene outer shell resists dents, scratches, and salt air


  • .95 EF
  • Well insulated for reduced standby heat loss
  • Pipe wrap energy saving kit included to achieve maximum energy savings


  • FHR: 42 - 61 gallons, depending on model
  • Recovery: 21 GPH at a 90° F rise

Easy Installation & Service

  • Marathon’s lightweight tank is easier to maneuver and position. Bowl shaped tank bottom drains completely.
  • Bowl shaped tank bottom allows complete sediment draining
  • Water tight grommets keep out overhead moisture and condensation


  • Thermally fused upper element provides protection against dry-firing
  • Titanium lower element for superior resistance to lime build-up
  • Full-flow, brass drain valve
  • Temperature and pressure relief valve
  • Low Lead compliant
  • Standard replacement parts



  TALL  30 MR30238 -- 
    30  MR30245 -- 
40 MR40245 --
    50 MR50245 --
  SHORT 50 MSR50245 --
TALL 40 CMR40230  240V, 3.0KW
  40 CMR40245  240V, 4.5KW
  50 CMR50230  240V, 3.0KW
  50 CMR50238  240V, 3.8KW
  50 CMR50245  240V, 4.5KW
  75 CMR75238 240V, 3.8KW
  75 CMR75245  240V, 4.5KW
  85 CMR85245  240V, 4.5KW
  105 CMR105230  240V, 3.0KW
  105 CMR105245  240V, 4,5KW
SHORT 50 CMSR50230  240V, 4.5KW
  50 CMSR50245  240V, 4.5KW
Available in US and Canada

  • The most durable electric water heater ever made
  • High efficiency design and a lightweight tank that won't corrode
  • Seamless polybutene tank – impervious to rust and corrosion
  • 30, 40 and 50 gallon capacities


Specification Sheet (US & Canada)
Use and Care Instructions (Canada FR)
Use and Care Instructions (US and Canada)


Detailed warranty information can be located in the “Use and Care Instructions”.
“Use and Care Instructions” can be found under the “Specs/Docs” tab

KwikComfort® Financing can help make your purchase even easier.
Rheem makes it easy to find a financing option that works for you! With many options and benefits available, KwikComfort Financing is the best way to get the home comfort you need without the wait.

  • Applications made easyWe'll help you avoid lengthy contracts, headaches and hassles.
  • Kwik credit decisionsYou'll get an answer to your application within minutes.
  • Fast credit for the futureFinance your Rheem equipment and anything you want to add later.
  • Reduced interest/fixed paymentsGet low interest and fixed monthly payments until the purchase is paid.
  • Minimum monthly paymentTake advantage of convenient monthly payments that fit your budget.
  • Deferred interest/no interestEnjoy interest-free payments as long as the balance is paid by the due date.
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