Actually the water coming out is crystal clear and doesn't smell at all... On warm days I'll fish it this time of year and do quite well. Hair jigs and silver buddies...
No doubt it's pretty clean when the system is not overwhelmed. And dont' forget they probably use Aluminum sulfate as part of their treatment.
BTW my newspaper editor told me he's actually seen toilet paper in the nearby St. Joe River (South Bend), which is known for it's steelhead runs.