Water quality - how you can help

In Cairns we are fortunate to live in one of the wettest parts of Australia and enjoy a quality lifestyle that the natural water cycle provides.

Our city's man-made urban water cycle has evolved around development and population growth. A network of council managed pits, pipes, open channels and natural waterways has been created to provide drinking water to homes and businesses, to remove wastewater and sewage, and redirect stormwater (rain that falls on a roof or paved areas) away from homes and businesses into drains that eventually flow to the ocean and the Great Barrier Reef.

It doesn't belong in the drain ...

In Cairns, stormwater is not treated and can carry harmful pollutants from urban areas to the ocean. By understanding how pollutants and contaminants can enter our stormwater drains and impact on the health of our waterways, we can all make small changes to our daily habits, and continue to enjoy our creeks and rivers and ensure the future of the Great Barrier Reef.

Along with general litter the biggest stormwater pollutants are sediment, nutrients and pesticides. Other 'natural' pollution, such as leaves and garden clippings (green waste) and animal droppings that enter our waterways are harmful to aquatic life and humans.

  • Sediment includes soil erosion and runoff from building sites and unsealed roads. When sediment enters waterways it makes the water cloudy and murky (turbidity), which blocks out light and prevents vital vegetation from growing.The finest sediments can enter and block the gills of fish, reducing their ability to survive and reproduce.
  • Nutrients, such as nitrogen and phosphorus, are essential for plant and animal growth, however in large quantities they can be detrimental to the ecosystem. Common ways in which unwanted nutrients can enter the water are from sewerage, animal waste, fertilizers and cleaning products such as detergents and soaps.
  • Contaminants such as pesticides, herbicides and petrol based products can be washed into the stormwater system from homes and businesses.Many of these chemicals are not only toxic to wildlife but harmful to humans.
  • When green waste (organic material) enters waterways it decomposes and during this process consumes oxygen (dissolved oxygen). If the oxygen levels drop too low, there is not enough for animal survival and it can lead to ‘fish kill events’, where large numbers of fish die within a short period.
  • The most common litter found in our waterways includes-
    - plastic bags
    - coffee cups
    - cans and plastic bottles
    - old fishing equipment
    - cigarette butts;
    - and plastic straws.

What you can do to help

Council is responsible for controlling and maintaining stormwater systems. However, it is everyone's responsibility to reduce the amount of rubbish and pollution that is carried into the drains.

Use the table below to see how you can change your behaviour around your home and neighbourhood which will help our waterways and manage run-off to the Great Barrier Reef.

In and around the house and garden




What you can do

Washing your car on the street


Detergents run easily and quickly down the drain.

  • Keep soaps and suds out of the stormwater drain. Try and use biodegradable or non-toxic soaps that are phosphate free.
  • Wash your car on the grass or over gravel if possible or take it to a car wash. (Commercial car washes must drain their wastewater into the sewer systems, where the water is treated.)

Fertilising and watering your garden


Fertilisers add nutrients to plants and soils. If these enter waterways too many nutrients can encourage algae to flourish. Thick layers of algae (algae blooms) can cover the water's surface, cutting off sunlight to the plants below and killing them.

Algae produced by these blooms also plays a key role in helping Crown of Thorns Starfish larvae to survive and reach adulthood. This is a coral-killing starfish that has reached plague proportions on the Great Barrier reef and is one of its biggest threats.

  • Adjust your sprinklers or irrigation systems to prevent water from draining onto paved surfaces such as footpaths and driveways.
  • Use fertilisers and garden chemicals sparingly, or those with no-phosphorous or organic alternatives.
  • Native plants often have longer root systems, which reduce the amount of chemical and water needed.
  • Use mulch or compost in the garden to prevent soil from washing away.
  • Reduce water run off at home by installing rain water tanks or building a rain garden that slows run off.
  • Plant grass, shrubs and trees at home and along creek beds to prevent erosion and trap other sediments.

Hosing your footpath and driveway


Runoff from hosing down driveways can carry fertilisers and any chemicals into the stormwater drain.

  • Don’t hose driveways and paths. Instead sweep dirt onto gardens or place in the bin.
  • Make sure runoff doesn't carry any chemicals into the stormwater drain or your local waterway.
  • Keep cars maintained so that they don’t drip fuel or oil onto driveways.

Disposing of house and garden rubbish

 Correctly disposing of soil and sand from construction or landscaping projects is critical to keeping sediment out of stormwater drains.

Wind and rain can carry garden rubbish into nearby drains. When green waste decays in water it uses up oxygen, taking vital oxygen away from plants, fish and other aquatic animals
  • Make sure you put the right rubbish in the right bin, including garden green waste, or take it to Council’s transfer station.
  • Sweep up leaves and put them in your compost bin or waste bin.
  • Dispose of chemicals at Council’s transfer stations, not in the drain.
  • Prevent dirt from entering drains by covering dirt piles with tarps, especially when transporting in a trailer.

Draining your pool

 Chemicals in swimming pools may be essential to keep your pool clean but can be harmful to the ecosystem. 
  • Avoid backwashing water from swimming pools into stormwater drains.

In your neighbourhood




What you can do

Walking your dog

 Bacteria from dog poo can enter  waterways and be a health risk to humans. 
  • Always pick up dog waste in a bio-degradable bag and put it in a bin.


 Litter is not only a major contributor to visual pollution of creeks and rivers but clogs waterways and causes toxicity as it breaks down and can cause harm to local wildlife. 
  • If you see litter, pick it up – and encourage others not to drop it.

Construction sites


Soil and sand from construction sites makes waterways cloudy and reduces light penetration and affects photosynthesis, the process that allows plants to use light as their source of energy.

  • Let Council know if you see sediment being washed into creeks and rivers.
Last updated: 28 February 2019