Part 2 in a series on water safety in Iowa. Read Part 1. Iowa’s riskiest drinking water comes from private wells, experts say. “We have lots of regulations governing the safety of every other source, but private wells are pretty much unregulated,” said David Osterberg, a professor in the University of Iowa’s Department of Occupational and Environmental Health. Private wells are not only unregulated but often untested and untreated, added Peter Weyer, director of the UI Center for Health Effects of Environmental Contamination. The older and shallower the well, the more vulnerable it is to contamination, according to Osterberg.