Well, the municipal water is the first issue, and the subject here. And it has been tested exhaustively, with the results reported.
People are free to test any water at any depth they want on their properties to complement government tests.
Over what period of time was the water tested exhaustively? I've read that contaminants from the train derailment would be anticipated to reach Cincinnati this weekend. I'm not being an alarmist, but a skeptic toward exhaustive testing before arrival. We could call it the pre-test baseline phase up to now.