You are correct that it doesn’t mean safe but most of the time the EPA sets their standards quite beyond what is actually safe. I could see testing and informing the community of the dangers but doing a cost benefit analysis from three thousand miles away leaves a lot to be desired. That should be done by the community that will have to pay for it.
I agree with a lot of what you said, except the flow of water either above ground or below does not give much heed to artificial community boundaries. What’s needed for you depends on where you get your water