Marathon offers 2 40 gallon water heaters models in the lineup we track. This page is the Marathon-specific cut of the broader 40-Gallon Water Heaters water heaters category — same product class, narrowed to the Marathon catalog only.
Marathon (Rheem) — subsidiary of Rheem. Specialty water-heater manufacturer serving the US market.
For the complete Marathon lineup across all sub-types and capacities, see the Marathon Water Heaters hub.
If you're cross-shopping 40 gallon water heaters beyond Marathon, the following brands also ship in this category:
The 40-gallon water heater is the volume size for 2–3 person households — second only to 50-gallon in residential install volume. The 40G saves $30–$80 upfront vs the 50G and fits the same standard 22"-diameter footprint with slightly less height. For 1-bathroom homes and smaller households, 40G is often the right sizing.
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