Sewage on sea is generally the waste produced from toilets, urinals and scuppers. The rules say that the sewage can be discharged into the sea water only after it is treated and the distance of the ship is 4 nautical miles from the nearest land.

Discarding sewage produced onboard on a ship is one of the few tasks on a ship which should be taken utmost care of if one wants to save him and his shipping company from heavy fine. The sewage generated on the ship cannot be stored on the ship for a very long time and it for this reason it has to be discharged into the sea. Though sewage can be discharged into the sea, we cannot discharge it directly overboard as there are some regulations regarding discharging of sewage that needs to be followed.