The Water Cycle

We use water every day, but we don’t often stop to think where it's from or where it goes! Take a journey with us to follow your water, from the clouds, to your taps, to a sewage treatment plant.

use mouse or finger to scroll down to begin

No new water can ever be made. The same water cycles continuously through a process called the natural water cycle, again and again.

              The Natural Water Cycle video (40 sec)

The urban water cycle describes the new journey water takes when people use it, treat it and return it to the environment.

Discover the urban water cycle

              The Urban Water Cycle Video
(36 seconds)

Did you know?

People need water for everything we do! We use water in our homes, communities, farms and businesses. In fact, we each use around
160 litres every day!

Key terms to remember

Evaporation - The sun heats the water in our oceans, lakes and rivers changing it from a liquid to a gas. The water vapour rises into the sky.

Transpiration - Plants take up water from the soil with their roots. They release some water into the air as water vapour through small holes in their leaves.

- Water vapour cools when it is high in the sky and turns back into liquid as tiny water droplets forming clouds.

Precipitation -
Water falls from the clouds back to the earth as rain, snow, sleet or hail.

Run-off – Water flowing off the land into rivers and streams.

Infiltration - Water soaks into the soil.

Groundwater - Water found underground in the cracks and spaces in soil, sand and rock.

The Natural Water Cycle

Water evaporates from the oceans and waterways by the sun’s heat.

The sun’s heat causes the water to change into gas and rise into the air (evaporation).

The gas begins to cool when it is high in the sky and turns back into a liquid as tiny water droplets form clouds (condensation).

The clouds become heavy and the water falls from the sky as rain, sleet, hail or snow (precipitation).

The water that falls to the earth can run off into waterways, or absorb into the ground (infiltration) where it may sink deeper into aquifers and underground water pockets (percolation) that exist naturally below the surface of the earth.

The cycle begins again.

The water from the dam is transported to a water treatment plant to be cleaned before it is used.

Did you know...

In our region, the water falls from the sky into dams. The water is treated at a water treatment plant managed by Seqwater.

The clean water is pumped underground to a Unitywater reservoir.

Key terms to remember

- A large wall or barrier that stops the flow of water, forming a reservoir or a lake.

Water Treatment Plant - A facility that takes fresh water from the environment and cleans it so it is safe for humans to drink.

- A large dam or storage facility that stores water.

Water is stored in a water reservoir or tower until it is needed.

Art meets water storage

Who would have thought a reservoir or water tower could be beautiful? Unitywater works with local communities to paint artworks on their water reservoirs and towers. Explore the videos below and see if you recognise one you've seen near your school or home.

How many water reservoirs and towers does Unitywater manage?
Unitywater manages 88 water reservoirs and towers across the Moreton Bay, Sunshine Coast and Noosa regions.
Where are they?
Check them out on this map (click to zoom) ... See if you can find the one closest to your school.
Every time you shower, wash your hands, use the toilet, wash dishes or clothes, the water you use becomes dirty. This water is called sewage.

Did you know?

Putting the wrong things down your sinks, drains and toilets can cause all sorts of problems in your home and impacts on the sewerage network. It can:

• block or damage your home’s sewer pipes
• cause problems at the sewage treatment plant
• harm the environment and health of our waterways.

Unitywater is responsible for removing and treating your sewage.  Your sewage flows through underground pipes from your house to a Unitywater sewage treatment plant.

Did you know?

Sewage doesn’t just disappear when you flush the toilet or drain the sink. It must be treated or cleaned before we can return it to the environment.

Unitywater is responsible for removing and treating your sewage. Your sewage flows through underground pipes from your house to a Unitywater sewage treatment plant.


Storm water that runs off roads and roofs is collected in storm water drains. It travels through pipes to waterways.

Think at the sink

Putting the wrong things down your sinks and drains can block and damage your pipes, causing sewage overflows in your home.

It also impacts our sewerage network. It causes blockages and overflows at our sewage treatment plants.
Please do not put these nasties down the sink or drain:
• Fats, oils or grease (from the kitchen or car)
• Solvents, paint and turpentine
• Chemicals, herbicides and pesticides
• Plastics including food wrappers and apple stickers
• Food scraps including egg shells, bones and cooked rice
• Dairy products
• Coffee grounds

              What could be lurking in your pipes? (37 second video)

              Some things should never be flushed video (2 min)

Do you love your loo?
Of course you do... (everyone does!)

Poo Quiz... Which of these can you flush?
Watch the video to find out....
The sewage you flush down toilets, sinks or drains travels through an underground network of pipes with the help of pumping stations.

              Why is sewage treatment important? (45 seconds)

Key terms to remember

Pump Station
- A facility that pumps water from one place to another. A pump station transports the clean water to your house, and the sewage to the treatment plant.

Sewage - All the used water that goes down our sinks, out of the shower, from our washing machines and toilets.

Sewage Treatment Plant
- A facility that cleans sewage so that it is safe to return to the environment.

Treated effluent - Water that has been cleaned at a sewage treatment plant.

The Sewerage Network

The sewerage pipes, pumping stations and sewage treatment plants are part of the sewerage network.

What is sewage?

More than 99% of sewage is just water. The remaining 1% contains:

• Micro-organisms such as bacteria, viruses and protozoa.
• Nutrients such as nitrogen and phosphorus.
• Solids such as dirt and other large items.

These nutrients can cause disease and harm our environment. This is why Unitywater’s sewage treatment process is so important. The sewage is treated at a sewage treatment plant to remove these harmful elements.

              The sewage treament plant (4 minutes)

Without safe sewage treatment, our life would be very different!
What's the risk?
Algae takeover! Your sewage contains high levels of phosphorous and nitrogen. These nutrients can cause outbreaks of algae and weeds in waterways, and reduce the amount of oxygen available for plans and fish.  Sewage treatment safely removes these harmful nutrients
Anything else?
Illness and disease outbreak! The bacteria in sewage can cause diseases such as Diarrhea and Cholera.The viruses in sewage cause diseases like Hepatitis. The protozoa in sewage can cause diseases such as Giardia and Dysentery.
Sssshhhhhh... don't tell anyone...
Tell anyone what?
I got hold of the keys to the sewage treatment plant... Want to come inside and check it out?
How many sewage treatment plants does Unitywater manage?
Unitywater manages 17 sewage treatment plants across the Moreton Bay, Sunshine Coast and Noosa regions.
Where are they?
Check them out on this map (click to zoom) ... See if you can find the one closest to your school.
Unitywater's treatment plants remove bacteria, contaminants, organic and inorganic matter in sewage.

This process reduces nutrients such as nitrogen and phosphorus to protect the environment and support our communities.

              Sewage Treatment Plant - Virtual Tour (7 min video)

The cleaned water is called effluent. This effluent is returned to a waterway to join the water cycle. Some effluent is used by industry and agriculture as recycled water.

After all that learning about water, you must be thirsty... which water source will you choose?

Plastic! That's not so fantastic!

Look around you and you will see so many things made from plastic, but all this plastic is starting to really impact our environment and wildlife.

Did you know Australians drink 726 million litres of bottled water every year - and only 18% of the plastic water bottles are recycled.

The rest ends up as landfill or as litter. Plastic drink bottles have been found to make up 40% of the litter in our environment.

Take a journey with us to see what really happens to a single use water bottle.

Plastic facts

  • One million plastic water bottles are used
    every minute
    all over the world.
  • Plastic never actually breaks down, it only breaks down into smaller pieces.
  • Researchers predict that by 2050 the ocean will contain more plastic (by weight) than fish.

Where does plastic go?

  • Recycling – plastic bottles can be recycled, but only 18% of disposable water bottles in Australia are recycled.
  • Landfill – some water bottles are sent to landfill, where they decay and can leach chemicals into the earth.
  • Litter – an unknown amount of water bottles is discarded as rubbish in streets, parks and public places.
  • Ocean – bottles can blow into drains and gutters, where they make their way to waterways and the ocean. They break apart into tiny pieces of plastic and can wash up onto beaches.

What does it all cost?

  • It is estimated Australians spend $2 billion on bottled water each year.
  • More than $20 million is spent on litter clean ups in Queensland each year.
  • A single use bottle of water costs around $3.50 for 600 mL.
  • Tap water costs less than 1c per litre.

Are you ready to change the story?

You can help to reduce these impacts by simply swapping single-use plastic water bottles for reusable bottles.

Join Unitywater and go Back To Tap!

Back To Tap! That's fantastic!

The global issue of plastic waste can seem overwhelming. But one very easy way to make a difference locally is to swap single use plastic water bottles for reusable bottles.

Reusable bottles can be filled with tap water over and over again, so you can easily cut down on the amount of single-use plastic in your world with this one simple change.

Plastic pollution - the issue

Take a journey with Brittany and Tim Silverwood of War on Waste and Take 3 for the Sea to find out about the impact of single-use plastic and why it’s important to get back to tap!

Plastic pollution - what's the solution

Follow Tim and Brittany as they explore one of the easiest ways to reduce your plastic waste - swapping single-use water bottles for reusable bottles filled with tap water.

Why use tap water?

  • Tap costs less than bottled water.
    More than 90% of the costs of bottled water are linked to the bottle, lid and label.
  • Tap has no packaging.
    Plastic water bottles are made from crude oil, a non-renewable resource.
  • Tap is a fresh and healthy choice.
    The water supplied to your tap is treated as a food grade product and meets stringent quality guidelines.
  • Tap is convenient.
    Unitywater supplies fresh drinking water to your tap 24 hours a day, seven days a week.

Become a Back To Tap school!

  • Unitywater’s Back to Tap program can help you reduce plastic waste at your school!

    Talk to your teacher or parents today if you’d like to be involved in:
  • Fun plastic-prevention activities
  • Unitywater visits to your schools
  • Chilled water refill stations and re-useable water bottles at your school
  • Book The Back to Tap van at your events

Mark Visser goes 'Back to tap'

Exploring the sewage treatment plant
Every sewage treatment plant is slightly different but they all use similar processes.

Chat with Unitywater scientists, engineers and Sir Sludge to find out more about the process or tap the video button to take a virtual tour.

* This interactive webstory about the water cycle is designed for tablets, laptops and desktop computers. If you are viewing on a mobile phone, please turn horizontal.