I am talking about water wells that are drilled. If it's necessary to drill 80-220 feet to reach water for the drilled water wells, then it seems unlikely that there will be abandoned 'hole in the ground' water wells on the prairie ... but anything is possible.
It sounds like that body of Septic Tank Sam was found in a septic tank on an abandoned farm property. The property that is being searched appears to be from the 1960s or 1970s and was probably agricultural land before it was subdivided into 40 acre parcels. I would be very surprised to learn that there was an abandoned well, abandoned septic tank, bomb shelter, or tornado shelter on the property.