Marpol Annex 4 Sewage

International Sewage Pollution Prevention Certificate? (ISPP)

Ships engaged in international voyages that are  400 gross tonnage and above or certified to carry more than 15 persons.


  1. drainage from any form of toilets and urinals;
  2. drainage from medical premises (dispensary, sick bay, etc.)
  3. drainage from spaces containing living animals; or
  4. other waste waters when mixed with the drainages defined above.”

Equipment included in the certificate:

  1. Sewage  treatment  plant
  2. Comminuter
  3. Holding  tank
  4. Shore discharge pipeline and connection

Sewage Systems

Every ship which, in accordance with regulation 2, is required to comply with the provisions of this Annex shall be equipped with one of the following sewage systems:

  1. Sewage treatment plant approved by the Administration, OR
  2. Sewage comminuting and disinfecting system approved by the Administration.
    • Such system shall be fitted with facilities to the satisfaction of the Administration, for the temporary storage of sewage when the ship is less than 3 nautical miles from the nearest land, or
  3. a holding tank of the capacity to the satisfaction of the Administration for the retention of all sewage, having regard to the operation of the ship, the number of persons on board and other relevant factors.
    • The holding tank shall be constructed to the satisfaction of the Administration and shall have a means to indicate visually the amount of its contents.”

Additional Guidance

MGN 280 – Small Vessels in Commercial Use for Sport or Pleasure, Workboats and Pilot Boats – Alternative Construction Standards.

MGN 385 – Guidance on the Merchant Shipping (Prevention of Pollution by Sewage and Garbage from Ships) Regulations 2008

The discharge of sewage into the sea is prohibited, except when the ship has in operation an approved sewage treatment plant or when the ship is discharging comminuted and disinfected sewage using an approved system at a distance of more than three nautical miles from the nearest land.

Sewage which is not comminuted or disinfected may be discharged at a distance of more than 12 nautical miles from the nearest land when the ship is en route and proceeding at not less than 4 knots, and the rate of discharge of untreated sewage shall be approved by the Administration