Find out about this innovative process and how it's helping to reduce our dependence on rainfall and securing a sustainable water supply for the future.

What is groundwater replenishment?

It's an innovative concept where treated wastewater is purified beyond drinking water standards and recharged into our groundwater supplies. The purified recycled water can then be stored in our underground aquifers, which store and naturally filter the water until we need it. It doesn't rely on rainfall and has the potential to recycle large volumes of water naturally and sustainably.

Currently, groundwater replenishment makes up 4% of our Integrated Water Supply Scheme

How does it work?

Watch our video about what happens at an advanced water recycling plant.


Read a transcript of this video

A first for Australia

We were the first utility in Australia, and among the first in the world, to replenish our groundwater supplies this way. Our groundwater replenishment scheme is located in Craigie, in Perth's northern suburbs. The first stage started recharging purified recycled water to Perth's deep aquifers in 2017. By 2022, the second stage of the groundwater replenishment scheme was completed. This expansion doubled the scheme's recharge capacity from 14 billion litres to 28 billion litres of water per year. 

The full-scale scheme will recharge the Leederville and Yarragadee Aquifers onsite, with the remaining volume of water transferred to recharge bores drilled in Wanneroo and Neerabup.


In 2012, we completed a successful three-year groundwater replenishment trial at our Advanced Water Recycling Plant in Craigie, The trial confirmed it could be used as a sustainable option to boost drinking water supplies.

The trial achieved its objectives to:

  1. Prove technical feasibility.
  2. Establish a framework for policy and regulation – recycled water produced by the plant must meet Department of Health and Australian Drinking Water Guidelines before it is recharged.
  3. Ensure sufficient community engagement and acceptance, gaining support from Perth residents, business and government.

The trial was overseen by regulators, the Department of Health and Department of Water and Environmental Regulation (formerly Department of Water and Department of Environmental Regulation). They continue to regulate the full scale scheme.

Before wastewater reaches the Advanced Water Recycling Plant, it has already undergone rigorous treatment at the Beenyup Wastewater Treatment Plant.

At the Advanced Water Recycling Plant, it undergoes further advanced treatment processes that included ultrafiltration, reverse osmosis and ultraviolet disinfection. This removes chemicals and micro-organisms to meet Australian guidelines for drinking water.

Image of wastewater treatment process

There are several water quality checkpoints (known as critical control points) throughout the treatment process to ensure each stage of the plant is working at an optimum levels.

If water does not meet the required standard when it reaches a check point, it triggers an alert for action to be taken. For example, we may divert the water to waste or temporarily shut down the plant.