I'm not far from Flint either and the fault was not with the water, end of conversation.
The fault was lazy buggers not thinking and taking a different water supply and not treating it properly so that the protective layer built up on the dangerous pipes, (installed before they knew the danger), broke down and exposed the population to a heavy metal that doesn't promote well being in the human body...
Now we have that little fib out of the way let's proceed...
I lived a year or so in Belize - right next to the Belize River that flowed past the International Airport and on down through Belize City into the lagoon. Being military we were under fairly strict orders not to swim in the Belize river. If you've ever seen it you'd know why...
I can't recall how many times I'd find myself on the swing bridge in the center of Belize City throwing Belizean quarters into the river while the local urchins jumped the 15 plus feet from the bridge into the murky filth below only to come up with the quarter less than half a minute later. I saw the same urchins day after day after day... and they were always healthy and well fed... I knew some by name and by their speed of recovery of the coin.
We inherited a boat from the film crew of a movie that was filmed there and we often took it down the river and out into the lagoon. We'd snorkel, water ski and generally screw off for entire days only coming home in time for our evening meal.
We had one chap who was a bit of a star on the old water skis and, despite better advice, decided he would ski the three odd miles up the river from the lagoon to camp... Everything was going spiffingly until we rounded a pretty sharp bend just short of camp and barely avoided a huge log floating down stream... Pigpen, as was his nickname, didn't see it until a bit late. He tried desperately to avoid it but it was unsuccessful. He hit it with both skis and went face first into the genetic soup that is called the Belize River.
It seems that he got a lovely shot of the soup straight to his gut and, as was the orders for such a situation, (falling in the river ;-) ), went straight to the Medical Center.
Five days later and about 15 pounds lighter Pigpen was sent back to our room. He had puked and squirted a volume that he claimed exceeded the entire volume of the Belize River yet, funnily, those urchins were in there daily with no mal-effect.
We will all adapt to the water provided, period. Those who spend more on a gallon of water than they do an a gallon of gas are little more than fools that have been convinced by slimy, suit wearing, parasites that their product is parasite free...