Water & the environment
See also
Related resources
- Requirements for publishing pollution monitoring data ()
Questions and answers
Find answers
- What is wastewater?
Wastewater is all the used water that goes down the drain from baths, showers, sinks, toilets, washing machines and dishwashers. It’s not just from homes – but also from schools, businesses and industry.
In a perfect world, wastewater would only contain water and the 'three Ps' – pee, poo and (toilet) paper. Unfortunately, it also contains:- food scraps
- coffee grounds
- cooking fats and oils
- soap and detergents
- wet wipes
- fragrances and other chemicals.
All of these can cause problems with your plumbing - and make it harder for us to do our job.
We collect and clean the wastewater from nearly five million people every day. We pump it through pipes to one of our 30 wastewater treatment or water recycling plants. We then clean the wastewater so it can be safely recycled or released back into local waterways.
Learn more about our wastewater network.
Why do you need to look after your pipes?Property owners are responsible for the pipes between the connection point to our system and their home or business.
If you put the wrong things down sinks, drains or toilets, they can clog your plumbing.
The two main causes of blocked pipes are:- flushing wet wipes and bathroom products down the toilet
- rinsing cooking fats and food scraps down the sink.
When oil and grease hit the cool water in your wastewater pipes, they harden. They then combine with other waste, like wet wipes, to form a hard blockage known as a 'fatberg'.
These blockages can cause overflows with wastewater overflowing into homes, backyards and local waterways. What’s more, you could be looking at an expensive plumbing bill to fix a blocked drain.
Find out more about why you should Clean up not down. - How can you help us manage trade wastewater?
Sydney's wastewater system was originally designed to transport wastewater from homes.
As Sydney has grown, so has the number of commercial and industrial operations. This has resulted in an increase in:- the amount of trade waste discharged to the wastewater system
- demand on our treatment plants
- demand on our waterways.
How you can helpTo help us manage the wastewater system, please remember that:
- all wastewater that enters our system comes out somewhere - either in the form of biosolids, recycled water or treated wastewater that's discharged to rivers or the ocean
- the more waste you put into the wastewater system, the harder our treatment plants have to work. This uses more energy, water and chemicals to keep up with the high levels of treatment required
- solid materials and grease can cause blockages in the wastewater system, resulting in overflows
- people work in and around the wastewater system, and can be harmed if you discharge dangerous materials
- the more we keep out of the wastewater system, the better it is for the environment.
- What is a wastewater overflow?
Wastewater is the used water that goes down sinks, toilets and drains.
When our wastewater network is blocked or becomes full, wastewater can 'overflow' from pipes to the local environment or within private properties.
Overflows in dry weatherDry weather overflows are often caused by blockages in wastewater pipes. About 70-80% of blockages are caused by tree roots.
You can help stop blockages by:- choosing the right trees
- making sure you don't plant trees near any pipes.
Overflows in wet weatherDuring heavy rainfall, the wastewater system can become affected by stormwater.
Usually, stormwater is separate from the wastewater system. However, sometimes stormwater can enter the wastewater system from:- cracks or faults in wastewater pipes
- an illegal stormwater connection into the wastewater network
- landscaping that diverts stormwater into manholes or overflow relief gullies.
If a lot of stormwater enters the wastewater system, the system can become overloaded. This can result in wet weather overflows. - Which trees can damage wastewater pipes?
Tree roots are a common cause of damage to wastewater pipes. They can enter small cracks in your wastewater pipes to seek out nutrients and then continue to grow. As they grow, they take up more space and slow down your drainage. This can eventually cause a blockage.
Signs of a blockage can be:- slow drainage
- gurgling noises in sanitary drains
- odour
- overflows in your home and property.
What can you do to prevent blockages?
Before you plant trees on your property, find out where your wastewater pipes are. A sewerage service diagram will show you. You can get one online through Sydney Water Tap inTM
As a guide, don't plant trees within six metres of any wastewater pipes. Your local nursery can give you advice on trees and their root systems.
If you have existing trees and they're a problem, ask a plumber to set up a regular maintenance plan for you.
The only things you should flush are the three Ps - pee, poo, and toilet paper. While some brands of wet wipes might say that they’re flushable - they aren't!
Which trees should you avoid planting near wastewater pipes?
Tree species vary greatly in their ability to enter the wastewater system and cause damage.
The trees listed below are likely to cause problems to your wastewater pipes. We recommend that you don't plant these species within six metres of a wastewater pipe.
Botanical name Common name Acer sp. Maple (mostly large) Araucaria sp. Norfolk Island Pine Bambusa sp. Bamboo Brachychiton Acerifolius Illawarra Flame Tree Callistemon sp. Bottlebrushes Casuarina sp. Casuarinas or She-Oaks (especially River Oak and Swamp Oak) Celtis sp. Nettle-tree and Hackberry Chamaecyparis/Cupressus sp. Cedar and Cypress Cinnamomum Camphora Camphor Laurel Erythrina sp. Coral tree (large) Eucalyptus sp. Gum trees (large) Ficus sp. Figs (Moreton Bay Fig, Weeping Fig, Rubber Tree) Fraxinus sp. Ashes (large) Jacaranda Mimosifolia Jacaranda Lagerstroemia sp. Crape Myrtle Liquidambar Styraciflua Liquidambar Lophostemon Confertus Brush Box Magnolia sp. Magnolias (large) Melaleuca Paperbarks Metrosideros Excelsus New Zealand Christmas Tree Morus sp. Mulberry (especially Black Mulberry) Murraya Paniculate Orange Jasmine Nerium Oleander Oleander Persea Americana Avocado Phoenix Canariensis Canary Island Date Palm Pinus sp. Pine Platanus sp. Plane trees Populus sp. Poplars Prunus sp. Apricot, Cherry, Peach, Plum Quercus sp. Oaks Salix sp. Willows Sapium Sebiferum Chinese Tallow Tree Schefflera Actinophylla Umbrella Tree Schinus Molle Pepper Tree Syzygium sp. Lillypilly Ulmus sp. Elms (large) Wisteria sp. Wisterias What can you do if you have a blockage?
If you think you have a blockage, we recommend you contact a licensed plumber for advice and a quote for repairs. - What are we doing to service new growth areas?
Sydney is entering a period of rapid growth.
Without investment in water infrastructure, growth isn't possible.
We're planning to invest about $800 million to enable growth across greater Sydney. Most of the investment will be in Sydney’s north west and south west.
We're servicing new growth areas by:- installing new networks
- upgrading our water and wastewater infrastructure.