I went fishing last year in a boat and drifted into the sewage outlet area. About 100 yards brown circle with a lot of floating shit and bog paper. Its just about 400 yards off the Sandy bay beach where the holiday camp people swim without knowing of the sewage.
SW water were heavily fined for deliberate sewage discharges but are now finding how they can dump it in the sea without being caught.
I suppose if the pipe went 1 mile out, it may be safe. There are no fish in the sewage pipe area but a lot of gulls picking up shit.