Many thanks to Byron Dorough, one of our water supply enthusiast followers for supplying the photos and info for this story. Byron found this 30,000-gallon tank while traveling through Billings, Montana and snapped a few photos. The concrete tank is located at the entrance to a small, residential development and most likely was installed as fire protection water for the development. We also suspect that the tank was required by local code in order for the property to be developed. From the ISO perspective, the 30,000 gallon capacity is the minimum impounded quantity of water that can receive certified suction point credit (250 gpm for 2-hours). While we often see photos of cylindrical plastic tanks used for fire water storage tanks, there clearly are other ways of achieving the same goal.