Recycling and reuse

Water is meant to be reused

A key part of our corporate strategy is to eliminate waste, or recycle and reuse the by-products of our activities. We're investigating innovative technologies and designing our systems to maximise recycling and reuse water and energy. We're working to restore and regenerate the natural environment and reduce our carbon footprint. 

We’re committed to recycling and reuse to help create a better life for all our customers and communities.

Reducing our carbon footprint

The used water and solids from wastewater treatment contain valuable resources we can recover and reuse, to minimise our impact on the environment. 

Along with recycling, we're committed to protecting and maintaining the environment through renewable energy and efficiency initiatives to reduce our carbon footprint. Our recycling program is diverse. It includes: 

  • water recycling at our water resource recovery facilities
  • treating wastewater solids to produce biosolids
  • using renewable energy created from our treatment processes at our water resource recovery facilities
  • recycling other resources.

We're always looking for more ways to reuse and recycle our resources, working with other agencies, businesses and research partners to develop innovative recycling solutions.

Water recycling

Nature is the world’s biggest water recycler. All water on earth is used and reused in an endless cycle – the natural water cycleWe use technology to speed up this natural process, so we can reuse this precious resource without relying entirely on rainfall. It also reduces the impact of waste on the environment.

We've been recycling water since the 1960s. We started with small irrigation projects and now produce billions of litres of recycled water each year. We provide recycled water for:

  • homes
  • businesses, including industry
  • golf courses and sportsfields
  • farms
  • a river system.

What is recycled water?

Recycled water is wastewater that's been used in homes and businesses and treated so it's safe to reuse. We put it through a multi-step treatment process to remove impurities so the purified recycled water can be used in many ways.

Did you know?
While about three quarters of the Earth is covered in water, we can only use a small portion. Most is salt water. Of the fresh water, much is frozen or groundwater that's deep underground. With less than 1% of the world’s water available to use, it’s important that we use and reuse it wisely. 

How recycled water is produced

Recycled water can be produced using:

  • water resource recovery facilities
  • sewer mining
  • on-site systems
  • stormwater harvesting.

Recycling and reusing water means we don’t need to depend as much on rainfall and reduces the amount of waste going to the environment. 

Recycling also ensures we have extra water available to supply Greater Sydney's growing population in case of drought.

Read more about producing recycled water.

Water resource recovery facilities produce clear high-quality water.

Using recycled water

How much we treat recycled water determines what it can be used for. We treat it to a high standard, suitable for its intended purpose. We don't currently supply recycled water for drinking and so we don't treat it to drinking water standards. 

We monitor closely to ensure it meets strict recycled water quality guidelines, so it's safe to use:

  • in homes and businesses 
  • in industry 
  • to irrigate parks, farms and playing fields
  • for river health.

Did you know?
In some parts of the world, including Perth and Singapore, very highly treated recycled water is an important part of the drinking water supply. 

Producing biosolids

Recycled water isn’t the only thing we produce at our water resource recovery facilities. We also produce biosolids – the nutrient-rich by-product of the wastewater treatment processes.

Biosolids are a rich source of phosphorus and nitrogen and can be used in agriculture, land rehabilitation, horticultural processes and mining.

Each year, we produce around 180,000 wet tonnes of biosolids from Sydney's wastewater. The strictly regulated process allows 100% beneficial reuse in agriculture. This results in greater crop yield for Australian farmers and improved environmental outcomes.

We support the Australian and New Zealand Biosolids Partnership.

How we know that biosolids are safe

The NSW Environment Protection Authority (EPA) and NSW Health advise that biosolids are safe if produced and used in line with their guidelines. We meet all the requirements in the guidelines.

To learn more about the biosolids guidelines, visit NSW EPA and NSW Health.

How biosolids are produced

When solids are separated from wastewater during the wastewater treatment process, they go through biological treatment. This reduces pathogens, odours and particles that attract insects and vermin. 

All biosolids we produce are tested at laboratories to ensure they comply with regulations to protect human health and the environment. Our $25 million biosolids program uses the latest technology and treatment processes. This ensures we can:

  • recover resources for a range of uses
  • continue to protect public health
  • reduce odours
  • reduce operational costs. 

Find out more about How biosolids are produced (167KB).

How biosolids can be used

Examples of biosolids use

Benefits of biosolids


Nutrients from biosolids are released slowly during plant growth. This increases crop production, provides superior water-holding properties and replaces nutrients removed from soil by harvesting.


Biosolids are mixed with other organic materials such as green waste, shredded timber and sawdust and allowed to compost naturally. This material is usually mixed into the soil to improve soil structure and help hold water.

Land rehabilitation

Biosolids are used to restore mine sites and degraded agricultural land.

How you can help us produce high-quality biosolids

  • Don't put paint, pesticides, medicines or other chemicals down the sink or toilet.
  • Do use low phosphorous or phosphorous-free detergents and pesticides.
  • Don't pour grease, oil or milk down the sink or toilet. It's best to bin it.

We use cogeneration to produce electricity at North Head.

Producing renewable energy

We're committed to protecting and maintaining the environment through renewable energy and efficiency initiatives. Renewable energy comes from natural resources that never run out.

Our Renewable Energy Generation Program is part of our pledge to reduce greenhouse gas emissions. 

Our program includes producing electricity:

  • using cogeneration – turning waste methane water gas (biogas) into electricity and heat at a number of our water resource recovery facilities
  • from hydroelectricity – using pressure reduction and gravity flow in treated wastewater and drinking water flows to generate energy. 

We use much of the renewable energy we generate to power our water resource recovery facilities. 

Find out more about energy management and climate change.

Recycling other resources

Our goal is to reduce waste through recycling and reuse and to encourage our suppliers to minimise waste. We avoid generating waste wherever possible.

Our waste procedure is consistent with the NSW Government's Waste Reduction and Purchasing Policy (WRAPP). We publish a yearly statement that outlines how we apply our waste reduction strategies. It includes details about:

  • reducing the amount of waste we generate
  • recovering resources by recycling and reusing them
  • using recycled materials. 

We store and reuse rainwater at our Potts Hill office.

How much can be recycled?
We recycled and reused 99% of all materials when we upgraded Warriewood Water Resource Recovery Facility.

See also

Circular economy

A circular economy aims to eliminate waste, reuse or recycle it. The purpose is to restore and regenerate resources, compared to a linear economy of taking resources, using them and disposing of the waste.