Here's a clue chief. Septic and storm sewer are different. The only way to get a visual of a septic sewer is to dig it up and break the pipes open, or screw caps off at a cleanout. Their are no exposed "manholes" in the septic sewer system.
Here's a clue ...Bzzzzzt!
NOT if you've got 50,000 (OR EVEN 10,000) residents using storm water to 'flush' their toilets (as some have said they are dong).
Some of you people, like you, have NOT thought this thing through completely.
SEWERAGE plants NOT operating, LIFT stations NOT operating; where does the effluent go if you flush a toilet?
Something is in your 'eye', guy, blinding you; you and and number of others.
Get out whatever it is.
There are exposed manholes in a city's sewer system. They are clearly marked sewer. Do a little research. But that doesn't matter. The area in the water has been contaminated and needs to be cleaned regardless of whether anyone else flushes their toilet. It is going to have to be cleaned anyway. It will naturally decontaminate itself when open to the air and dried. the remainder will be pumped into the lake which will empty into the ocean. This pollution is a drop in the bucket compared to what went into the Mississippi in the 30's 40's 50's and 60's. The Mississippi river was an open sewer for half the country.