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The first stage of research for the Anti-Ingestant Project was completed in August 2016 and the working group have recommended that a second research package is developed. The team are currently determining the appropriate regulatory approval pathway and are scoping the second package of work. This is expected to be completed in mid 2017.


The Anti-Ingestant Project commenced in May 2016. Luke Dickson from Yarra Valley Water is project manager.

In April 2016 the IWN Executive approved the business case for the Anti-Ingestant Project which will investigate the concept of adding a bittering agent (denatonium benzoate) into the Class A recycled water supply to identify cross-connections. A cross-connection is when the recycled water supply is incorrectly connected to drinking water taps.

Cross-connections - or non-compliant customer plumbing - can result in recycled water being plumbed to drinking water taps, leading to the consumption of recycled water and creating potential health impacts. This project presents an opportunity for utilities to improve the way they manage this risk. If proven, it is expected to both lower the health risk and provide financial savings.

The Anti-Ingestant Project aims to provide utilities with enough information to determine whether adding an anti-ingestant to the supply is a viable method for identifying cross-connections within their operating environment. Anti-ingestants create a noticeable change in a substance, making it less likely to be consumed. For this project, the proposed anti-ingestant will create a bitter taste in the water.

The first stage of the project will be to review and evaluate prior research completed by Sydney Water and Yarra Valley Water. A working group has been formed to complete this review and to set the direction of the project.

If the group find that the anti-ingestant additive provides a positive cost-benefit relationship, then the project will move to the second stage - implementation in a recycled water system at one of the participating water corporations.

The Anti-Ingestant Project working group currently comprises:

  • Nick Crosbie (Melbourne Water)
  • Trevor Hayes (Western Water)
  • Dale Husted (Coliban Water)
  • Li Gao (South East Water)
  • Brad Pett (Barwon Water)
  • George Ruta (City West Water)
  • James Cleaver (VicWater)
  • Rowan Keeble (IWN) and
  • Luke Dickson (Yarra Valley Water).