Tank capacity is somewhat misleading. I have inspected water heaters for 12 flats that are similar in size to a 50 or 75 gallon tank but the recovery rates are 200 gallons/hour! Many home owners believe bigger is better for this appliance and that is simply not true.
Tankless water heaters are coming but thats a completely different discussion. In the mean time, think "recovery rate" and a relatively small tank capacity.
|Tank capacity is 38 gallons/hour (blue oval) and the recovery rate is 39.32 gallons/hour (red oval)|