Ranger:
Undoubtedly, the city of Chicago does, at times (and it's allowed, to a certain extent) discharge raw, untreated sewage to the river. This is mainly because of what's known as "combined sewer overflow". Storm water drains that (years ago) were connected with the sanitary sewers.
You get a big rain, and the sewage treatment plants cannot handle (nor were they designed for) this huge surge of rainwater and sewage combined. They are forced to then discharge directly to the river.
I'm on a septic system and it's a surface discharge. I'd love to install a drain field and may be forced to do so in the future. For now, it discharges into a drainage that feeds directly into my newest pond. Next summer, I plan to have that pond's water analyzed for E coli, fecal coliform and maybe some other things. I'm in the ENV. field, so I've got the contacts and it's pretty cheap.
Assuming the dang pond ever fills, I feel that the amount discharged by my wife and I will have little impact on the quality of the water, but I'll confirm that...but probaby won't swim there.
If I ever sell the house and a small acreage, I'll be forced to install a sand mound, as I'll not risk letting anybody else discharge to my pond. We damn careful about what goes down the tube here, others might not be. Got a buddy with the backhoe, trackhoe and mini excavator, so really the cost would be the pipe, stone, sand and fuel (maybe $1000). It's just that our lawn only just got back to normal after the major excation of 4 years ago (new basement) and I'm not looking forward to digging the dang thing back up just yet.
Direct surface discharge is far from ideal, but the alternative is beyond the means of many. I'd be in for about $4000 or more if I had to pay for all of it.
