Stormwater audit

Where does rain go in urban environments?

Urban environments are packed with hard surfaces that prevent rain from soaking into the ground. It flows from property drains to street gutters, and then to our large channels, pipes and creeks. It can pick up a lot of debris on the way. When you do a stormwater audit, you can locate your school’s stormwater drains and find out how polluted they are – and why – and how you can make a positive impact on reducing pollution in local waterways.

How much stormwater is running off?

Many schools have large areas of hard surfaces like roofs, car parks, basketball courts, assembly areas or concrete quadrangles. These hard surfaces increase the amount of stormwater run-off that goes down the drain.

You can estimate the amount of stormwater run-off by calculating the area of all the hard surfaces and miltiplying by the amount of rain in a storm. Remember to use the right units! You can check your rainfall history for your area.

What happens to stormwater?

Stormwater flows into small drains which lead to larger stormwater drains and eventually drain into local waterways. It picks up litter, leaves, dirt and anything else on the surface as it travels.

By taking the actions identified in your stormwater audit, you can help reduce pollution in local waterways.

Pre-audit investigations

1. Find an aerial map of the local community, centred on the school and showing the closest waterway. Maps are available from Google Earth or your local council. Look at the map to find where the stormwater from your school goes. This will usually be the closest waterway like a creek, river or ocean. If the map has contours (lines showing areas of equal height above sea level), this will help show which direction the water flows.
2. Discuss how clean the local waterway is and any obvious links to the stormwater drains in the school and local community. How can you tell how clean a waterway is?
3. Divide into groups with a scribe for each group. Each group should have an audit sheet and map of the school grounds showing all buildings. Some schools may be able to get a stormwater map from school asset managers.
4. Make sure everyone knows about being safe around stormwater drains by reading the safety section on our Stormwater page.

Review findings

After the stormwater audit, return to your classroom and review your data as a whole class.

How could you present your data in a meaningful way?

You might like to:

• make a pie graph to show which issues were most common
• make a bar graph that shows which location in the school had the best and worst drains
• create a class data set with other students. Compare your results.

After you've looked at your results, ask yourself:

• What are the main issues affecting the drains?
• What are causing these issues?
• What issues could be changed, eliminated or reduced and how? 

Make a change

Find out the many ways you can make a positive impact and spread the word.

Identify strategies to reduce stormwater pollution in your school. Include these in a School Water Management Plan that shows water use issues and suggests actions to help reduce stormwater pollution.

Communicate your findings

There's lots of ways to share your findings from the stormwater audit with students and staff at your school. You could:

• make a poster, infographic or flyer
• make a presentation or a video
• write an article for the school newsletter or website
• use social media.

You might like to try some Persuasive techniques (2.6MB) to encourage people to do the right thing.

Next steps

Don’t forget to celebrate your success! People like to know they’ve helped achieve something.

So, when you start seeing less pollution around stormwater drains, think about ways to tell everyone what a great job they’re doing and how they can do more.

Do a stormwater audit at home and share your new skills with your family, too.