Ok so partially treated sewage could equal 7.5 million gallons of treated and 7.5 million of raw untreated.

Or it could mean there was only 3 million treated gallons and 12mil untreated or vice versa...it has to be assumed at the worst because even a small percentage of untreated in ground water is a bio hazard

they say one quart of oil can ruin thousands of gallons of drinking water, so what do you think the chances of passing hep or worse is in untreated sewage?