I lived 3 blocks away from South Shore beach in Milwaukee - the sewer overflows hit the lake inside the breakwall and sit in mostly stagnant water.
It’s a shame because 75-100 years ago the beach was a big draw and people still go to the lake front to enjoy the paved Oak Leaf trail. I still work in the area but moved away a few years ago. The water isn’t obviously dirty but it has very high levels of the bugs that come from dumping municipal sewage. I cringe when I see people let their dogs swim in it.