Recycled water network

Recycled water is wastewater that's been collected and treated so it can be re-used.

We own and operate 14 water recycling plants. Another two plants are operated by other companies on our behalf. Our Gerringong-Gerroa plant is operated by Veolia. The St Marys Advanced Water Treatment Plant is operated by Deerubbin Water Futures.

Our water recycling plants treat wastewater:


This ensures recycled water is safe and suitable for its intended use.


Recycled water can be used to:

  • water gardens, golf courses and parks
  • flush toilets
  • wash cars
  • fight fires.


It can also be used for some industrial purposes and to supplement river flow in the Hawkesbury-Nepean River. This saves water stored in dams for drinking and keeps the river healthy.

Read about our projects that help recycle water using sewer mining and stormwater harvesting.

The wastewater transported to water recycling plants has already gone through many treatment steps. This includes filtering to remove nearly all biodegradable organic material and nutrients. It has also been disinfected.
The tertiary treated wastewater then goes through several processes that may include:
  • Passing through a mechanical strainer
  • Ultrafiltration to remove particles of organic matter that may still be present
  • Reverse osmosis – very fine sieves that extract water
  • De-carbonators that reduce carbon dioxide in the water.
Treatment plant Treatment level Discharge
(Ml/day)
Discharge location
Bombo Secondary and de-nitrification and disinfection 3.6
  • Headland north of Bombo Beach
Castle Hill Tertiary (includes additional Phosphorus removal and disinfection) 6.5
  • Cattai Creek
Gerringong-Gerroa Partial tertiary (includes screening, storm tank or primary sedimentation, ponding and chlorination) 0.7
  • Re-used for on-site agricultural irrigation
  • Excess discharged to sand dune systems. Once sand dunes reach capacity, excess is discharged to Crooked River
Glenfield Partial tertiary (includes screening, storm tank or primary sedimentation, ponding and chlorination) 0
  • Treated wastewater transported to Malabar
  • Occasionally discharged to Georges River in wet weather
Liverpool Secondary (includes screening, de-gritting, primary sedimentation, ponding and chlorination) 0
  • Treated wastewater transported to Malabar
  • Occasionally discharged to Georges River in wet weather
Picton Tertiary (includes additional Phosphorus removal and disinfection) 1.5
  • Re-used on-site for agricultural irrigation Precautionary discharge to Stone Quarry Creek
Penrith Tertiary (includes additional Phosphorus and Nitrogen removal and disinfection) 22.4
  • Re-used locally
  • Remainder transferred to St Marys Advanced Water Treatment Plant
  • Some excess discharged to Boundary Creek
Quakers Hill Tertiary (includes additional Phosphorus and Nitrogen removal and disinfection) 31.1
  • Re-used locally and at Ashlar Golf Course
  • Remainder transferred to St Marys Advanced Water Treatment Plant
  • Some excess discharged to Breakfast Creek
Richmond Tertiary (includes additional Phosphorus removal and disinfection) 2.2
  • Re-used for irrigation at University of Western Sydney, Richmond Campus
  • Excess overflows to Rickabys Creek
Rouse Hill Tertiary (includes additional Phosphorus and Nitrogen removal and disinfection) also includes ultra-violet irradiation and super-chlorination for reuse water 15.3
  • Recycled back to households for non drinking use
  • Excess discharged to Second Ponds Creek via wetlands to Cattai Creek
St Marys Tertiary (includes ultrafiltration, reverse osmosis, de-carbonation, additional Phosphorous and Nitrogen removal and disinfection) 33.5
  • Re-used locally and at Dunheved
  • Remainder discharged to Nepean River
  • Some excess discharged to South Creek
West Camden Tertiary (includes additional Phosphorus removal and disinfection) 10.7
  • Re-used at Agricultural Institute
  • Remainder discharged via Matahill Creek to the Nepean River
Wollongong Tertiary and disinfection 40
  • Re-used at BlueScope Steel
  • Remainder discharged via offshore outfall with diffuser zone

We do routine checks on the quality of our recycled water.

Our customers may use recycled water for:

  • industrial purposes
  • irrigation
  • approved uses in some residential areas, eg Rouse Hill residential scheme.


We check that the water:

  • is treated to the right level based on how customers will use it
  • meets the standards in the Australian Guidelines for Water Recycling.


If you live in an area that has recycled water or work for a company that uses recycled water, read more about using recycled water.

We use water from St Marys Advanced Water Treatment Plant to supplement flow in the Hawkesbury-Nepean River. Find out about the water quality in our Advanced Water Treatment Plant EPA pollution monitoring data reports.