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.
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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 resource recovery facilities
Most recycled water in Sydney and the Illawarra is produced at our water resource recovery facilities. 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.
Find out more about our recycled water network.
Treatment processes
All water resource recovery facilities 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 our facilities.
Port Kembla Coal Terminal uses recycled water for dust suppression.
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. These include irrigation, industrial uses, watering gardens and flushing toilets.
Advanced treatment
This step may include microfiltration, ultrafiltration and reverse osmosis. The filters used can trap particles smaller than a millionth of a metre.
This type of highly treated recycled water is for specialised uses. These include some manufacturing processes and 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 ultraviolet 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 method to produce recycled water. Wastewater is extracted from a local wastewater system and treated 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 sports fields, parks and golf courses.
Recycled water 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.
Setting up a sewer mining scheme
- Read our Sewer mining (975 KB) fact sheet.
- Download our Request for preliminary advice on sewer mining proposal form (180 KB).
- Review our Sewer mining agreement (198 KB).
Our Parramatta office uses recycled water to flush toilets.
On-site recycling systems
Recycled water is now 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 reuse stormwater.
Stormwater harvesting involves collecting, storing and treating stormwater from urban areas. This 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.
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.
Cammeray Golf Club's dam is topped up with stormwater, which is used for irrigation.
Stormwater harvesting schemes in Greater Sydney
The NSW Government encourages the private sector to implement innovative solutions to secure Greater Sydney's water supply, particularly by recycling.
Local councils are responsible for about 95% of stormwater drainage in the Greater Sydney Region. Most stormwater harvesting schemes are locally operated. A number of projects across Greater Sydney 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
- Review our Stormwater harvesting (1 MB) fact sheet
- Read our Stormwater harvesting and reuse agreement (353 KB)
Recycled water taps are coloured purple.
Using recycled water in homes
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, and should have a 'not for drinking' sign near it
- 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.
How you can 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 or pipe can be used 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 tap or pipe must not be used for:
- drinking or cooking
- bathing
- filling swimming pools and playing under sprinklers
- cleaning inside the house
- filling evaporative coolers.
How you can use recycled water
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Our residential water recycling schemes
We've supplied recycled water to the Rouse Hill area since 2001. The recycled system has its own pipeline and meters.
Rouse Hill Water Recycling Scheme
Our Rouse Hill Water Resource Recovery Facility provides recycled water to more than 30,000 properties in Sydney's North West through a dual supply scheme. This 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 scheme uses purple to identify the recycled water system.
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.
Using recycled water around the home saves valuable drinking water.
Using recycled water in industry
Using recycled water for industrial processes helps save large amounts of drinking water. Recycled water is used for:
- cooling towers
- boilers
- some manufacturing processes
- dust suppression.
Our water recycling map (541 KB) shows where these customers are located.
Our water resource recovery facilities are among the largest users of recycled water. About 96% of their 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 Rosehill.
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 supplied recycled water to some schemes since the 1960s.
Our water recycling map (541 KB) shows where our irrigation customers are.
Using recycled water for river health
We produce tertiary-treated recycled water for agriculture and irrigation at Penrith, Quakers Hill and St Marys water resource recovery facilities using screening, biological treatment and filtering. Some of this treated water is sent to the St Marys Advanced Water Treatment Plant.
At the advanced water treatment plant, we produce reverse osmosis recycled water. The recycled water is pumped through ultrafine membranes and reverse osmosis membranes, then disinfected.
This highly treated recycled water is released into the Hawkesbury-Nepean River system at Penrith, to:
- help reduce nutrient levels in the river
- boost river flows, especially in dry times
- replace some of the flow that would otherwise have to be released from Warragamba Dam, Sydney's major drinking water supply.
The St Marys Advanced Water Treatment Plant uses ultrafiltration and reverse osmosis technology to produce high quality recycled water.
St Marys Advanced Water Treatment Plant is 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 that produces recycled water on this scale and quality to improve river health.