Perth engineers have reached a new milestone with their non-climate dependent water solution that bolsters the state’s supply.
Australia has a long history of managed aquifer recovery (MAR) – the longest-serving being the Burdekin Delta scheme that has operated continuously in Northern Queensland since the 1960s – but the Perth project is the first to use purified, treated wastewater to bolster drinking water supplies.
Groundwater replenishment currently makes up 5 per cent of Western Australia’s Integrated Water Supply Scheme.
In 2022, engineers in Perth unveiled the country’s first ever full-scale groundwater replenishment scheme using potable quality water, to help address growing water demand in a warming climate.
And this year, the scheme reached a major milestone, with 100 billion L of purified recycled water recharged into climate-impacted groundwater aquifers.
With the state’s Water Corporation aiming to achieve a recycled wastewater target of 35 per cent by 2035, let’s take a look at the innovative approach to water management.
Check out the below infographic to learn more.
Regional water utilities often face the largest challenges when providing safe drinking water and reliable sewerage services.
And when the people get to know they are drinking 40% treated wastewater? You can tell them it is purified to more pure than rainwater, but that will not stop honest prejudice, let alone activists. Plan B? Or is there no Plan B?
What about In the context of the groundwater replenishment discussion, Perth’s drainage challenges are often treated with unnecessary complexity. Much of the metropolitan area sits on Bassendean Sand or its variants, with infiltration rates well exceeding 10m/day. The plains are flat and undulating, and historically the landscape relied on depression storage to act as a sponge that passively recharged groundwater. This natural process meant surface waterways and runoff generation were limited. Assessments of undeveloped sites continue to confirm this behaviour.
Despite this context, extensive pit-and-pipe drainage systems are widely used. At scale these networks become deep, long, and hydraulically constrained. With no natural waterways to receive discharge, the adopted solution has often been the use of “bubble-up pits,” which surcharge and then flood the surrounding land. Because these pipes fall to the lowest points in the terrain, overflows have no path to escape and remain ponded until they evaporate or slowly move through dense organic topsoil.
Soakwells are common but prone to blockage because their infiltration surface area is small and maintenance is infrequent. There is generally no systematic method to detect when they have clogged.
Monitoring data from Perth Groundwater Atlas sites and geotechnical wells, including wells shown in the Atlas as having high water levels, actually show that many of these wells run dry not too long after rainfall events, including in areas with lower permeability. Large monitoring programs across multiple sites still consistently shows this pattern.
A broader issue is the habit of applying more infrastructure to treat symptoms rather than understanding how the landscape originally functioned and adapting solutions to suit it. Simple measures such as increasing perforations in drainage pipes can enable significant infiltration losses during storm events, provided infiltration pathways are confirmed. More engineered options, such as permeable concrete pipes (e.g., HydroCon), can achieve immediate infiltration benefits across entire networks without requiring additional downstream works. These types of approaches are likely to be far more cost‑effective over the long term. By comparison, the energy, carbon footprint, and operating costs required to treat wastewater and move it through advanced replenishment systems remain substantial.
In the UK today’s drinking water has passed through 12 human bodies before it gets to your tap. Do the public complain, purchase other drinking water or perhaps are unaware of this fact! I’ve never heard any complaints. What you don’t know you don’t grieve for. So – my view is ‘don’t tell me!’
What a great article with fantastic presentation.
These are exactly the kind of messages we need as an industry to get out into the general public. Only this way will we, over time, reduce the mindset that waste water can’t be treated for all beneficial uses.