Wastewater (sewage, greywater and bilge water)

Sewage, greywater and bilge water

The Marine Park’s crystal clear turquoise water is one of its most alluring qualities and never fails to draw gasps of delight and amazement.

Declining water quality is a serious issue for the Great Barrier Reef, especially inshore close to agricultural areas. How tourism operators use and dispose of wastewater can make a big difference to the quality of the water. Wastewater may contain high levels of nutrients, and coral reef ecology is extremely sensitive to even a slight decline in water quality.

Responsible Reef Practices

With bilge

  • Use a drip pan under the engine to reduce leaks into the bilge.
  • Do not pump bilge water overboard if oil is present in the bilge.
  • Use oil absorbent pads or towels to remove oil out of the bilge or other areas of the vessel. Don’t use a degreasing compound.
  • Pump-out your bilge on shore to licensed waste disposal contractors, if the facilities are available.
  • Use enzyme-based bilge cleaners – do not use detergents, degreasers or chemicals.

With greywater

  • Minimise water usage on vessels (for example, through flow restricted and auto-shutoff taps).
  • Discourage the use of soaps and shampoos. Use environmentally friendly cleaning alternatives such as phosphate-free and readily biodegradable soaps.
  • Use readily biodegradable and environmentally friendly chemicals for cleaning and maintenance.
  • Store greywater in holding tanks and pump it ashore, where possible.
  • If you must pump out greywater at sea, make sure you’re as far as possible from reefs and islands.

With sewage

  • Minimise sewage production (for example, by using low volume toilets).
  • Store all sewage in holding tanks, if possible, and use pump-ashore facilities, where provided.
  • If pumping ashore is not an option, installing a sewage treatment system will help minimise impacts.
  • If you must discharge at sea, pump-out in open water, as far as possible from reefs and islands.
  • If there is no holding tank, encourage clients to use the toilets when your vessel is well away from reefs and islands.
  • Use biodegradable toilet paper and phosphate-free cleaning products.

With spill response

  • Train your staff in proper reporting and spill response techniques.
  • Have an adequate spill response kit onboard.
  • Have procedures in place to deal with all types of spills.


  • Please report all marine pollution, including chemical, oil and fuel spills and suspected illegal disposal of wastes.

Marine Parks Legal Requirements

  • You must not discharge oil, oily mixtures or noxious liquid substances into the Great Barrier Reef Marine Park.
  • You must not bury or leave noxious, harmful or offensive substances in the Great Barrier Reef Coast Marine Park or on island National Parks.
  • You may pump out untreated sewage that has been reduced to a fine slurry in the Great Barrier Reef Marine Park if you are:
    • Outside a boat harbour, canal or marina, and
    • More than one nautical mile from the seaward edge of an aquaculture operation, and
    • In addition, if you carry 16 or more persons on board, you are at least one nautical mile seawards of the nearest reef; or the low water mark of the nearest island or mainland.
  • Under the Queensland Transport Operations (Marine Pollution) Act 1995 and Regulations (see Related Links), you must not discharge untreated sewage into Queensland coastal waters:
    • From a vessel with sixteen or more people on board
    • Within one nautical mile of a reef, or the mean low water mark of an island or the mainland from a vessel with seven to 15 people onboard.
    • Within one half of a nautical mile of a wharf or jetty and within one nautical mile of aquaculture fisheries resources from a vessel with one to six people on board.
  • In addition, you must not discharge treated or untreated sewage into prohibited discharge waters, including boat harbours, canals, marinas and designated areas within the Queensland Great Barrier Reef Coast Marine Park.
  • If you treat your vessel sewage then the areas where you may discharge vary according to the level of treatment.
  • Sewage effluent from land-based treatment facilities must be treated to a specified standard. You must have a Marine Parks permit to discharge such effluent.
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