Rapunzll,
I have lived in this area (Antrim & GTC) for 40+ years. When I was younger I was never told not to swim in the water, except for the occasional problem with "swimmer's itch" and this was is in Elk Lake..
Anyways I didn't say they closed the beaches, I said they won't let you swim in the water...
If more than 300 E.Coli/100ml are present in a water sample it is considered unsafe for swimming.
This is what I found for 2003
Kid's Creek @ 1,986/100ml on 8/26/03
Boardman River @ 517/100ml on 5/14/03
Suttons Bay Creek @ 727/100ml on 8/26/03
Traverse City State Park beach @ 518/100ml on 6/9/03
Milliken Park beach @ 2419/100ml on 6/09/03
So you're right, the beaches aren't shut down because that would be bad for tourism, but it doesn't mean that they are safe to swim in everyday.
But still a very scenic place to live, just don't drink the water
