The feedback period has now closed.


During times of heavy rainfall, some areas in Thornton can experience localized flooding. As Thornton is currently unsewered, this can present issues with greywater (waste water from baths, sinks, washing machines and other kitchen appliances) finding its way into stormwater systems, and in some cases this means it ends up in the Goulburn River.

As a result of this issue, Council will be upgrading Thornton’s Stormwater Drainage Network to help treat the grey water discharge.

The key objectives of the upgrade:

  • increase irrigation opportunity such as irrigation for recreational grassed space
  • resolve flooding and drainage issues
  • improve amenity, keeping our streets and river clean for everyone to enjoy

We are seeking community feedback on the final design of the ways we plan to treat greywater and the related works. Feedback will be open until Friday 10 December 2021.


Leave your feedback on the detailed Drainage Upgrade plans.

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The Network Upgrade explained

The Network Upgrade has been designed by an effective means of bio-retention, using water sensitive urban design (WSUD) principles. The proposed upgrade includes creation of an artificial wetlands, which will be connected to the current drainage system. These wetlands as well as the proposed upgrades to the existing drainage infrastructure are designed to accommodate a minimum 1 in 10 year Average Recurrence Interval (ARI). Average Recurrence Interval is the average or expected value of the periods between exceedances of a given rainfall total accumulated over a given duration. Please refer to the detailed plans for further information.

The Treatment Process explained

The drainage system will function in low flow rate processes. Normal low flow events will run all water through either a treatment plant or the filtration gardens.

High flow events for larger rainfalls will bypass the filtration and discharge directly to the rivers and creeks but at such volumes there is substantially less risk of contaminant causing problems.

To read a full summary of how the system works including background, challenges, risks and some technical information please click

Frequently Asked Questions:

The works will not affect residents or businesses in the Thornton area as we are not required to access the properties to undertake the works. Works for the Drainage Network Upgrade will be done underground using WSUD principles.

The grey water will no longer have a bad smell. The grey water will go directly to the treatment plants that will be largely underground as well as a filtration bed at the end of the drainage network to filter flows prior to discharge into the waterways.

No, vegetation won’t be impacted.

Currently planned for 2022/23 financial year. This is dependent on securing the additional funding required to complete the project.

The treatment plant will not have any negative impact on the community, it will however improve amenity by reducing previously experienced odors resulting from greywater flows.