Ron,
It is any one or more containers, 55 gallons or more, capable of holding 1320 gallons or more combined. Like I said in the main post, there is some leeway with the ability to physically seperate the "facilities" by placing a tank across the road at the other farm, on the other side of the tree grove by the house, over the section line, etc.

If you have 55 gallon drums on the premises and they are not in their own "facility" or in a building which can act as a containment, they need to be within that dike/containment if you are required to have one.