The reason an Anode Rod is required by a Suburban Water Heater is because the tank of the Suburban Water Heater uses glass enamel over a steel tank. If the enamel cracks for any reason it will expose the steel to the water and the steel will start to corrode even from a pinhole in the enamel. The rod attracts the corrosive elements in the water that could corrode the water heater tank and the rod itself gets corroded.

So why doesn't the Atwood need an Anode Rod? The water tank on the Atwood Water Heater is made of aluminum which does not have the same corrosive properties as steel

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