Among the aspects to be considered in the design of a sewer outlet are listed as under:
(a) Location to avoid unpleasant sight and offensive smell.
(b) Protection of the mouth of sewer if it empties into a river against swift currents, water traffic, floating debris, heavy waves, or other hazards which might damage the structure.
(c) Prevention of backing-up of water into the sewer if the outlet is having a flat grade.
The ideal location for an outlet is onto a swiftly running stream with currents that will always carry away floating and settleable matter that has not been removed by treatment processes.