Summary of Discharge Standards at the Port of Southampton

This guidance applies to the Port of Southampton Statutory Harbour Area. Advice on regulation in adjacent Harbour Areas should be sought from the relevant authorities – for example Queen’s Harbour Master Portsmouth and Cowes Harbour Commissioners. In the case of open water, questions should be directed to the Maritime and Coastguard Agency.


Ballast Water

The discharge of ballast water may be permitted subject to the vessel complying with the International Convention for the Control and Management of Ships’ Ballast Water and Sediments. The Convention requires vessels to have an operational water management system in place [D1 or D2 Standard] or to be able to demonstrate that ballast water has been exchanged or treated in open waters [200 nm from shore and in water at least 200m in depth]. Please refer to the IMO guidance for further information. Otherwise the discharge of ballast water is prohibited within the Port of Southampton harbour area.

Vessels wishing to discharge ballast water should contact Southampton VTS.

Dirty ballast water can, however, be discharged ashore for treatment.


The discharge of untreated sewage is prohibited within the Port of Southampton harbour area. Discharges from approved and certified sewage treatment plants is permitted provided the discharge is clear with no solid material.

Partially treated or disinfected sewage (grey water) discharges are also prohibited within the harbour area. Such discharges are, however, permitted at a distance of more than 3 nautical miles from land.

Untreated sewage (black water) must only be discharged at a distance of more than 12 nautical miles from land.

Tank Washings

Tank washing discharges are prohibited within the Port of Southampton harbour area.  


Issued 7 November 2017

Updated 8 May 2018



International Maritime Organisation

Queen’s Harbour Master

Cowes Harbour Commissioners

Maritime and Coastguard Agency