Comment Louisiana and Mississippi (Score 1) 242
All along the Mississippi River towns filter and purify water from the river for drinking, then treat their sewage and put it back into the river. If you drink the water near the delta then part of what you're drinking has been through dozens or hundreds of people.
Connecting the output to the input eliminates some of the waste of wastewater. It's good enough for NASA, so it's good enough for you.