- →Perth’s Groundwater Replenishment Scheme (Beenyup, Craigie) has recharged over 100 billion litres of purified recycled water into deep aquifers since 2017. It supplies 3–8% of Perth’s IWSS drinking water.
- ✓The treatment process — ultrafiltration + RO + UV — produces water so pure minerals must be added before it enters the aquifer. It is cleaner than the groundwater it blends into.
- →The pharmaceuticals question is a genuine area of ongoing research. RO removes the majority of pharmaceutical compounds. Over 70,000 GRS water quality tests have all met Australian Drinking Water Guidelines.
- !The quality concerns driving Perth filter purchases — groundwater hardness and chlorine — are unchanged by the GRS contribution. These come from the groundwater component, not recycled water.
- ✓If trace-compound certainty is a priority, an under-sink RO system applies the same treatment technology used in the Advanced Water Recycling Plant at the point of use.
Three very different things called “recycled water”
The phrase covers a spectrum of treatment levels and end uses that are frequently conflated:
- Class A+ recycled water (non-potable): Tertiary-treated wastewater for irrigation, industrial cooling and toilet flushing. Not for drinking. Supplied through a separate purple-pipe network. No drinking water standard required.
- Indirect potable reuse via groundwater replenishment: Advanced-treated wastewater (ultrafiltration + RO + UV) recharged into a deep aquifer, where it mixes with existing groundwater over months to years, then extracted, treated again, and supplied as drinking water. This is what Perth’s Groundwater Replenishment Scheme (GRS) does. This is the most relevant category.
- Direct potable reuse: Advanced-treated recycled water introduced directly into drinking water distribution. Not currently done in Australia, though under investigation for future supply augmentation.
Perth’s Groundwater Replenishment Scheme — how it works
Perth’s GRS at Craigie (Beenyup Advanced Water Recycling Plant) has operated at full scale since 2017. By March 2025, the scheme had recharged over 100 billion litres of purified recycled water into Perth’s deep aquifers. Stage 2 (commissioned 2022) doubled capacity to 28 billion litres per year — enough to supply approximately 100,000 households. The treatment process uses the same core technologies as seawater desalination, in sequence:
- Beenyup Wastewater Treatment Plant: Full secondary treatment to ocean-discharge standard.
- Coarse and fine screening: Solids down to 200 microns removed.
- Ultrafiltration: Hollow-fibre membranes remove suspended materials, bacteria and some viruses at 0.1-micron scale.
- Reverse osmosis: Removes dissolved minerals, micro-organics, pharmaceuticals and remaining pathogens.
- UV disinfection: Inactivates any remaining micro-organisms.
- Deep aquifer recharge: Pumped into the Leederville (300–500m) and Yarragadee (700–1,400m) aquifers, where it mixes over years.
- Extraction and further treatment: Later extracted, treated again, and supplied as drinking water.
Water Corporation states the purified recycled water entering the aquifer is so pure that minerals and chlorine must be added for it to meet drinking water standards.
What the treatment process removes
| Contaminant | Removed by AWT? | Key stage | Residual concern? |
|---|---|---|---|
| Bacteria (E. coli, Salmonella) | Yes — effectively complete | Ultrafiltration + UV | Negligible after full treatment |
| Viruses | Yes — effectively complete | Ultrafiltration + RO + UV | Negligible after full treatment |
| Pharmaceuticals & hormones | Yes — majority removed | RO (primary removal) | Trace levels at or below detection limits |
| Microplastics | Yes — effectively complete | Ultrafiltration + RO | Below detection in treated water |
| PFAS | Yes — majority removed by RO | Reverse osmosis | Near or below detection after RO + aquifer dilution |
| Heavy metals | Yes — largely removed by RO | Reverse osmosis | Below ADWG values after treatment |
| Dissolved minerals (hardness) | Yes — removed by RO | Reverse osmosis | Water enters aquifer very soft; picks up minerals in aquifer over time |
The pharmaceutical question — the honest position
This is the most frequently raised concern about recycled water. The RO stage used in the Beenyup Advanced Water Recycling Plant removes the majority of pharmaceutical compounds. Water Corporation and the Department of Health have published over 70,000 water quality test results from GRS trial and full-scale operation, consistently meeting stringent health and environmental guidelines. All results have met Australian Drinking Water Guidelines.
The honest position: long-term health effects of very low-level pharmaceutical exposure through treated recycled water are not yet fully characterised by epidemiological research — it remains a genuine area of ongoing scientific inquiry globally. However, the treatment process is specifically designed to address this concern, and available monitoring data does not show health-relevant compounds at detectable levels in the treated water at the point of recharge.
Water Corporation publishes annual Groundwater Replenishment Scheme Compliance Assessment Reports at watercorporation.com.au — one of the most tested water sources in Australia. The GRS is regulated by the Department of Health and Department of Water and Environmental Regulation.
How recycled water compares to current Perth tap water
The most counterintuitive finding: water entering the aquifer from the GRS is demonstrably cleaner than the groundwater it blends into on almost every measured parameter. The recycled water has passed through ultrafiltration, RO and UV. The existing aquifer water has moved through mineral-rich limestone geology for potentially thousands of years, carrying dissolved minerals, iron and other naturally occurring substances. After blending, the tap water profile is primarily determined by the existing aquifer water chemistry — the recycled component effectively dissolves into a much larger body of higher-mineral groundwater.
The quality concerns driving Perth filter purchases — groundwater hardness and chlorine — are characteristics of the groundwater component, unrelated to the GRS contribution.
The trajectory — what’s coming
Perth’s GRS currently contributes 3–8% of the IWSS. Water Corporation’s goal is to recycle 30% of treated wastewater by 2030, with groundwater replenishment contributing up to 20% of Perth’s total supply by 2060. Other Australian states are watching Perth’s GRS as a model — South East Queensland, Sydney and Adelaide all have indirect potable reuse under investigation or planning.
Does this change what filter I need?
For most Perth households, no. The hardness and chlorine concerns that justify filtration in Perth are unchanged by the GRS contribution. If trace pharmaceutical compounds are a personal concern, an under-sink RO system applies the same technology used in the Advanced Water Recycling Plant at point of use — addressing pharmaceuticals, PFAS, dissolved minerals and any other compounds simultaneously.
Perth's GRS is one of the most rigorously tested water processes in Australia. The water entering the aquifer has been through ultrafiltration, RO and UV — far more treatment than any other source in the network. The quality concerns driving Perth filter purchases are unrelated to the GRS contribution.
The long-term trajectory toward higher recycled water contributions is a supply security story, not a quality degradation story. Use our comparison tool to find suppliers with verified RO systems if trace-compound certainty is a priority.