Electric Water Heaters | Gas Water Heaters | Propane Water Heaters | Tankless Water Heaters Please click on a category to view products. Free Standard Shipping on Water Heaters shipped within the Mainland Continental United States Home » Commercial Water Heaters, Storage Tanks & Accessories » Natural Gas Water Heater » Extreme High Input Natural Gas Water Heaters » All ProductsView all products in all categories. Rheem GX X-Treme High Input, Natural Gas [More] ... [Less]