Investigation into drinking water quality at schools

I read a recent article on contaminants found at thousands of public and private schools across the United States that use well water. The article was based on an investigation by the Associated Press.

Given that problems were so common at schools who draw their water from wells, I have to wonder about the quality of drinking water found in the millions of homes that use well water. I would expect (at least hope) that school water would be cleaner and better treated than your typical residential system.

Has anyone seen data on water quality for residential well systems?