Where does stormwater go? - Ocean Protect Skip to content

Did you know the biggest source of ocean pollution is contaminated stormwater?

Over 500,000 litres of rainwater falls on an average suburban block each year. That’s more than 2,500 full bathtubs. During a big summer storm, about 90 bathtubs of water fall in less than 30 minutes.

So what happens to all that water?

Some ends up in rainwater tanks and some soaks into the landscape, but most becomes runoff collecting pollution like soil, leaves, dog poo, cigarette butts, and plastics before disappearing into the stormwater drain.

All sorted? Well no.

A large network of underground pipes move the stormwater rapidly out of the suburbs to prevent flooding and into nearby rivers and lakes where all these pollutants can cause problems. Problems like blue-green algae, water toxicity, horrible rubbish and microplastics.

Today local governments are responsible for stormwater infrastructure. In some locations pollution traps and trash racks are in place to catch most of the big rubbish. Unfortunately less than 5% of urban areas have any prevention in place. And where they are in place they are often not maintained.

Most stormwater, and the pollution it has collected, empties directly into our waterways. According to CSIRO, approximately 1,580 kilograms of plastic enters Australia’s oceans every hour. 


What can you do?

Make sure only water goes down the stormwater drain. Don’t litter, avoid single use, reduce, recycle, clean up your landscape debris and educate yourself and others. And tell your local government you support spending on infrastructure and maintenance that keeps our oceans clean. Ask your local council what they are doing to stop pollution enter their waterways?