At what volume does sewage become an issue to the environment? Is there a cut off point?

Question

At what volume does sewage become an issue to the environment? Is there a cut off point?

Answer 1

No, there is no cutoff point because there are too many variables.  If you are talking raw untreated sewage, a few hundred gallons in a small creek can be a problem.  For treated sewage, you will be talking millions of gallons.  If you are talking a large river, it would not even notice that 100 gallons of raw sewage.  Volume, type of sewage, receiving stream, treatment level, type of receiving stream, all impact the result.

Answer 2

It depends where the sewage ends up.  In Walkerton Ontario a lot of raw sewage from cattle farms washed into the drinking supply and a lot of people died of E-coli poisoning.