Reviews of the 5 Best 50 Gallon Gas Water Heater, Plus 1 to Avoid: When searching for a top-quality 50-gallon gas water heater that is worth the investment, you have to take several factors under consideration. Flow rate, energy factor, storage space, and durability are some of the critical factors to watch out for. In this detailed article, we’ll provide insight about the best 50-gallon gas water heaters available on the market.