One of the many midwestern properties that we researched for purchase was about 5 miles off the Mississippi River. When we talked to a couple of well drillers, they both concurred that we were lookin' at a 300+ ft well. They also talked of having to use sulfer tanks to make the water palatable. We ditched the property for numerous reasons, that just being one. I have no idea what these tanks look like, nor their effectiveness.