Producing recycled water

Keeping it clean and fit for purpose

We produce recycled water in various ways depending on what it will be used for. We treat it to a high standard, suitable for its intended purpose. Recycling is a vital part of our commitment to a circular economy and it's an important part of the story for the future of water.

Water recycling plants

Most recycled water in Sydney and the Illawarra is produced at our water recycling plants.

We produce recycled water and maintain our systems to meet the Australian Guidelines for Water Recycling to ensure it's safe for its intended use.

You can find out more about our recycled water projects and our recycled water network.

Port Kembla Coal Terminal uses recycled water for dust suppression.

Treatment processes

All of our water recycling plants use multiple steps to treat wastewater so it can be safely used again. How much we treat it depends on how the recycled water will be used. The process starts when wastewater (which is more than 99% water) from bathrooms, kitchens, laundries and businesses travels through pipes to treatment plants. 

Primary treatment

This step removes large solid particles from wastewater using screening, grit removal and sedimentation.

Secondary treatment

‘Good’ bacteria feed on and clean up organic particles and nutrients. Aeration, settling, clarification and chemical treatment may also be used.

This type of recycled water can be used for timed irrigation.

Tertiary treatment

Deep sand beds are used to filter out nearly all remaining organic particles and suspended material.

This type of highly treated recycled water is suitable for many uses including irrigation, industrial uses, watering gardens and flushing toilets.

Advanced treatment

This step may include microfiltration, ultrafiltration and reverse osmosis. These filters can trap particles smaller than a millionth of a metre. 

This type of highly treated recycled water is for specialised uses such as some manufacturing processes and for river flows. In some parts of the world, advanced treatment is used to produce water for drinking.

Disinfection and pH balance 

We disinfect all of our recycled water using chlorine and/or ultra violet light, to ensure it meets the requirements for the intended end use. We adjust the pH level to make sure the water is not acidic.

Sewer mining

Sewer mining is one of the many ways the NSW Government is securing our water supply for the growing population.

It's another way to produce recycled water by extracting wastewater from a local wastewater system and treating it on-site using a small treatment plant.

Recycled water must be treated so it's safe to use for its intended purpose.

Recycled water produced from sewer mining is used:

  • to flush toilets in commercial buildings and at industrial sites 
  • in cooling towers
  • to irrigate sportsfields, parks and golf courses.  

Recycled water produced from sewer mining can be used for irrigation.

Sewer mining schemes in Greater Sydney

The NSW Government encourages the private sector to implement innovative recycling solutions to secure Sydney’s water supply. These are some of the sewer mining schemes in Greater Sydney. 

Sydney Olympic Park

Sydney Olympic Park at Homebush was Australia’s first large scale, urban recycling scheme to source wastewater through sewer mining. Recycled water is used for irrigation and other non-drinking purposes. Recycled water replaces 50% of the drinking water that would otherwise be used at Sydney Olympic Park and Newington Estate.


Pennant Hills Golf Club

Pennant Hills Golf Club’s water reclamation plant produces up to 100 million litres of recycled water each year to irrigate the golf course. Previously, the course relied on drinking water for irrigation. This sewer mining project was the first of its kind for a privately run golf club in Australia.


Workplace 6

Workplace 6, on Darling Island in Sydney, is the first commercial development in NSW with a six-star Green Star energy rating. The environmentally sustainable office building has an on-site sewer mining facility. It produces up to 14 million litres of recycled water each year to flush toilets and irrigate two parks.


Setting up a sewer mining scheme

Our Parramatta office uses recycled water to flush toilets.

On-site recycling systems

Recycled water is now being used for non-drinking uses in some Sydney offices and commercial sites.

Our Parramatta office has a recycling plant that produces up to 40,000 litres of water every day. This reduces the building's water use by about 75% compared to similar buildings without a recycling plant.

Sydney Airport also saves drinking water by using an on-site water recycling plant. Recycled water is used to flush toilets and in cooling towers.

Setting up a water recycling system

It’s important to look at the full range of water saving options when you start out. Often, improving water efficiency is more cost-effective than setting up a new water recycling system. Our Water recycling (6 MB) fact sheet will help you work out if your scheme is viable.


Stormwater harvesting

Stormwater is another source of recycled water. We work with local councils and other agencies to manage Sydney’s stormwater. We also investigate opportunities to collect and re-use stormwater.

Stormwater harvesting involves collecting, storing and treating stormwater from urban areas, which can then be used as recycled water. The stormwater is collected from stormwater drains or creeks, rather than roofs.

Recycled water produced from stormwater harvesting is commonly used to water public parks, gardens, sports fields and golf courses.

Cammeray Golf Club's dam is topped up with stormwater, which is used for irrigation.

Benefits of stormwater harvesting and reuse

Stormwater harvesting:

  • reduces the demand for drinking water  
  • reduces stress on urban streams and rivers by capturing some of the pollutants and nutrients that would otherwise enter waterways from stormwater flows
  • increases opportunities for sustainable water management. This is an important consideration in water sensitive urban design.

Stormwater harvesting schemes in Sydney

The NSW Government encourages the private sector to implement innovative solutions to secure Sydney’s water supply, particularly by recycling.

Local councils are responsible for about 95% of stormwater drainage in the Sydney region. Most stormwater harvesting schemes are locally operated.

There are a number of projects across the Sydney region that collect and reuse stormwater. We generally don't have a role in establishing or operating small local schemes. However, we'll help arrange access to the stormwater supply from our stormwater system.

Setting up a stormwater scheme

Did you know?
We've installed 69 Stormwater Quality Improvement Devices to help clean stormwater. These include trash racks, litter booms and sediment traps.

Using recycled water in homes

Recycled water taps are coloured purple.

Recycled water supplied to the community and business isn’t treated to the same standards as our drinking water, so we supply it through a separate system. These are clearly identified and coloured purple.

You have recycled water at your property if:

  • you have a second water meter that's purple
  • your garden tap is purple. It should have this sign near it: 'Recycled water – do not drink'
  • you have recycled water charges on your bill.

Some new homes may have a recycled water connection in the laundry for the washing machine. The tap or connection will be clearly marked.

Did you know?
There are many cities around the world that use recycled water as part of their drinking water supply. Some places you might like to learn more about are Perth, San Diego and Singapore.

How to use recycled water

If you have recycled water at your home, you need to know how to use it. Recycled water that comes from purple taps is not suitable for drinking.

Recycled water from a purple tap/pipe is great for:

  • watering lawns and gardens, including fruit and vegetables 
  • flushing toilets
  • washing cars
  • filling ornamental ponds
  • fighting fires
  • washing laundry in a washing machine (you need the right plumbing for this).

Recycled water from a purple pipe is not for:

  • drinking or cooking
  • bathing
  • filling swimming pools and playing under sprinklers
  • cleaning inside the house
  • filling evaporative coolers.

Our residential water recycling schemes 

We've supplied recycled water to the Rouse Hill area since 2001 with the recycled system having its own pipeline and meters.

Rouse Hill Water Recycling Scheme

Our Rouse Hill Water Recycling Plant provides recycled water to more than 30,000 properties in Sydney's north-west through a dual supply scheme.

We’re proud to say this is the largest and one of the oldest residential water recycling schemes in the world.

The area serviced with recycled water includes all or parts of Acacia Gardens, Beaumont Hills, Castle Hill, Glenwood, Kellyville, Kellyville Ridge, Parklea, Quakers Hill, Stanhope Gardens, The Ponds and Rouse Hill.

Learn more about using recycled water in the Rouse Hill area:

Hoxton Park Water Recycling Scheme

Hoxton Park Water Recycling Scheme is designed to provide recycled water to parts of new residential suburbs and industrial areas in Sydney’s south-west. 

We plan to start operating this scheme when there are enough properties built and connected to our recycled water pipes.

About 5,000 properties have connected to the Hoxton Park scheme so far. We need another 1,500 homes to connect so we can ensure there's enough demand for us to efficiently operate the scheme and produce recycled water that meets the Australian Guidelines for Water Recycling.

Learn more about Hoxton Park Water Recycling SchemeFor more information call us on 13 20 92.

Using recycled water around the home helps to save valuable drinking water.

Recycled water and Water Wise Guidelines
Water Wise Guidelines don't apply to recycled water. The guidelines only apply to drinking water. So you can use recycled water at any time under the Water Wise Guidelines. However, all water is precious so it's still important to use recycled water wisely at all times. Check out our water wise tips for easy ways to save water in your home and garden.

Using recycled water in industry

Using recycled water for industrial processes helps save large amounts of drinking water. Recycled water is used in industry for:

  • cooling towers
  • boilers
  • some manufacturing processes
  • dust suppression.

Our map shows where these customers are located.  

Our wastewater treatment plants are among the largest users of recycled water.

About 96% of our plants' water needs are met with recycled water – that's about 15 billion litres of recycled water a year.

BlueScope Steel in Wollongong uses recycled water.

Industrial recycled water schemes in Greater Sydney

Our major recycling schemes are in Wollongong and Rose Hill.

Wollongong Water Recycling Scheme

Our water recycling plant at Wollongong, which has been operating since 2006, uses micro-filtration and reverse osmosis membrane processes to produce very high quality recycled water. The water is suitable for a range of industrial purposes.

We also produce tertiary treated recycled water at this plant.

We supply:

  • up to 7 billion litres of high quality recycled water to BlueScope Steel from Wollongong Water Recycling Plant each year
  • recycled water to Port Kembla Coal Terminal. The coal terminal started using recycled water in 2009. It uses about 450 million litres of recycled water each year, reducing fresh water use by over 70%.
Rosehill Recycled Water Scheme

Rosehill Recycled Water Scheme is a private sector project that began operating in October 2011. The scheme supplies over 3 billion litres of recycled water a year to major industrial customers and a racecourse in the Rosehill and Smithfield areas.
AquaNet Sydney (a division of Jemena) built, owns and operates the scheme. It works in partnership with Veolia Water and is supported by Sydney Water.

Recycled water helps keep plants healthy

Using recycled water for irrigation

The amount of recycled water used by customers varies, depending on the weather and other factors.

We supply recycled water for irrigation to many different types of customers including parks, sports fields, golf courses, farms and race courses. We've been supplying recycled water to some schemes since the 1960s.

Our map shows where our irrigation customers are.


Using recycled water for river health

We produce recycled water at the St Marys Advanced Water Recycling Plant and release it at Penrith into the Hawkesbury–Nepean River. This project links three major water recycling plants (at St Marys, Quakers Hill and Penrith) and sends the treated water into the Hawkesbury–Nepean River system at Penrith.

  • helps reduce nutrient levels in the river
  • boosts river flows, especially in dry times
  • replaces some of the flow that would otherwise have to be released from Warragamba Dam, Sydney’s major drinking water supply.

It’s Sydney’s largest water recycling project, producing over 10 billion litres of very high quality recycled water a year.  As far as we know, it’s the only plant in the world producing recycled water on this scale and quality to improve river health. 

The Advanced Treatment Plant at St Marys uses ultrafiltration and reverse osmosis technology to produce high quality recycled water.

This project shows how we treat water to be fit for its intended purpose:

  • We produce tertiary treated recycled water for agriculture and irrigation at Penrith, Quakers Hill and St Marys Water Recycling Plants using screening, biological treatment and filtering.
  • We take some of this treated water and send it to the St Marys Advanced Water Recycling Plant where we produce reverse osmosis recycled water for the Hawkesbury-Nepean River. The recycled water is pumped through ultrafine membranes and reverse osmosis membranes, then disinfected. See the diagram to learn more about the process.

See it yourself

If you're interested in taking a free tour to find out more about water recycling, you can request an excursion at St Marys Advanced Water Recycling Plant. 

Did you know?
Recycled water used from the St Marys Advanced Water Recycling Plant, which is used for river health, is similar in quality to distilled water. 

Dual supply scheme

A dual supply scheme is where a second water supply (such as recycled water) is delivered through a separate supply system, with its own reservoirs, pipeline and meters. Our dual supply shceme uses purple to identify the recycled water system.

Green Star

Green Star is a rating system for environmental design and construction. Six stars, the highest rating, is for world-class projects.