Recycled water supply update - 15 April

Werribee recycled water update

Melbourne Water supply Class A recycled water to Southern Rural Water, who in turn supply the water to our Werribee Irrigation District customers.

Melbourne Water paused supplying recycled water to Southern Rural Water on Tuesday, 30 December 2025, because the Blue Green Algae cell count exceeded the acceptable supply limit. There is currently no confirmed timeframe for when recycled water supply will resume.

We’re sorry to hear the challenges this has caused some of our customers and at a time of economic uncertainty due to other factors associated with fuel and material price increases, we’re working hard to find immediate and short-medium contractual improvements to support our customers.

Alternative Water Supply now made available for WID Recycled Water Customers

In response to the outage Melbourne Water (MW), Greater Western Water (GWW) and Southern Rural Water (SRW) have worked together to provide the Werribee Irrigation District (WID) recycled water customers with a temporary alternative water supply.

The alternative water supply is available to WID recycled water customers until mid-June 2026. SRW has secured the transfer of up to 1.3GL of SRW water from the Yarra–Thomson pool to Werribee recycled customer using GWW's water network.  

FAQs

What is the supply capacity of the GWW network to provide the Yarra-Thompson water?

Based on the capacity of the GWW water supply network, the supply to the WID will be at least 15ML/day. 

Does this impact allocations or next season?

River Water supply and allocations are unaffected by this benefit, and the normal water schedules for Werribee customers remain in place as normal. 

This one-off benefit has been secured for a 10-week period and does not adversely impact any other SRW customer groups or other Irrigation Districts. Using this water will reduce the need to draw down more water from the Melton Reservoir, thereby, maximising the water available for next season starting allocation.

What will it cost recycled water customers to access the Yarra-Thompson Water?

This water will be supplied to recycled water customers for the same rates as their normal recycled water rates.

Recycled Water Customer Billing

Quarter 2 Bills – normal supply period

Recycled customers will shortly receive their normal Quarter 2 bills for recycled water for the period October 2025-December 2025. This was the period before the outage. To assist at this difficult time for some, we have extended the due date for this Q2 period to 21 August 2026. 

Quarter 3 Bills – outage period

We understand the frustration and we’re sorry to hear the possible impacts this outage has had on some customers and all Water Authorities are working collaboratively to mitigate immediate impacts as well as work on solutions for the future. 

Consistent with previous years where outages have occurred, SRW and MW are working together to minimise the impact of the outage this financial year. This includes support with billing and payments. The Quarter 3 bills are being further delayed to give customers the choice to pay once we have the agreed any payment support that we can pass back to our customers.

Background on Blue-Green Algae impacting recycled water in the Werribee Irrigation

What is the current Recycled Water BGA count now?

What is Blue Green Algae?

Blue-green algae is a naturally occurring group of micro-organisms present in both fresh water and salt water. Under certain environmental conditions, these cells can grow rapidly or ‘bloom’. The lagoon treatment process at Melbourne Water’s Western Treatment Plant for Class A recycled water contains nutrient rich water which – when combined with warmer weather – create conditions for a variety of algae species to grow, including blue-green algae.

The Blue Green Algae Emergency Response Plan, published by the Department of Energy, Environment and Climate Action (DEECA), includes guidance on the limits beyond which blue-green algae is considered a public health risk.

For general use of recycled water, Melbourne Water follows the recommendations set by DEECA and will cease supply of Class A recycled water if the blue-green algae cell count exceeds the limit published in this guide for swimming. For agricultural uses, Melbourne Water has reviewed the trigger for resuming recycled water supply and updated it from 50,000 to 150,000 cells/mL for three days in a row, based on a safety assessment specific to agricultural irrigation. 

Southern Rural Water notifies our customers when the cell count reaches 10 percent of the limit as a safety reminder.

More information about blue-green algae can be found on our blue-green algae warning page.

What is Melbourne Water doing to seek to tackle the BGA challenges?

What is the current peroxide treatment trial? 

A large-scale peroxide dosing trial started on 5 January 2026.

This is the third year of peroxide trials that Melbourne Water has progressively scaled up from laboratory testing and small-scale pilot plant studies, through to a series of 24-hour tests at full-scale operation. Tests are advancing to continuous full-scale dosing over the whole bloom season. 

So far, trials demonstrate scalability and efficacy, and it's likely to be the most feasible solution for blue-green algae control at waste stabilisation ponds.

When is the ultrasonic trial planned?

A trial using a commercially available ultrasound unit for controlling blue-green algae is planned to be implemented in mid-2026. 

What other trials have been investigated?

Copper based algaecides are commonly used to control blue green algae at small scales, particularly in water bodies that don't discharge to marine environments. Melbourne Water conducted a small-scale trial using coper-based algaecide in 2022 to determine its effectiveness and the rate at which copper was removed from the system.

Copper is toxic to shellfish and other marine species at relatively low concentrations. Unfortunately, the trial showed that copper remained persistent in the process and was ineffective at controlling the algal bloom, making it not a viable option.

No further trials using copper-based algaecides to control blue-green algae are planned.

Investigations found that a small-scale trial using ozone would not be safe for staff to implement without costly and complex control measures. 

What's being done by the water authorities to secure a longer-term solution?

New Systems

Southern Rural Water and Melbourne Water are both committed to securing a high-quality, reliable recycled water product for Werribee growers through the Werribee System Reconfiguration project.  

Growers and our project partners Department of Energy, Environment and Climate Action, Melbourne Water and Greater Western Water have pledged their support for the preliminary business case.  

We submitted a funding application for further developing the business case to the National Water Grid Authority and we’re awaiting a final decision.  

In addition, Melbourne Water committed to investing in improvements to recycled water infrastructure as part of its Price Submission 2026-31. The investments included the renewal and improvement of chlorine treatment infrastructure to be delivered by 2028/29, additional treatments for blue green algae to provide reliability in 2027 and carbon dioxide dosing upgrade to improve pH and reliability.

Re-thinking our contracts

1 July 2026 signals the start of a new contract period for recycled water supply to WID customers. We’re re-thinking how to approach the next contracts and will be working with customers in the coming months to seek to understand how the next year could work differently from a contractual perspective, acknowledging this is the 4^th year of BGA impacting recycled water supplies. 

Contact us         

If you wish to lodge a complaint, Southern Rural Water is committed to responding or passing on complaints or feedback as appropriate.

Please call 1300 139 510 or email srw@srw.com.au

Our Customer Charter can be found here.