Blue-green algae caution for channels

Thursday 11 March, 2021
Goulburn-Murray Water (GMW) is advising water users to exercise caution with channel water due to the potential for harmful levels of blue green algae to be present.
GMW Water Quality Manager Greg Smith said investigation of reports of possible blue green algae in some channels this year had confirmed that some algae levels exceeded human health guidelines for contact.
While blue-green algae is nearly always present in waterbodies, slow flowing and stagnant waters are more favourable for growth as the algae can more readily access sunlight. As a result, channels that do not flow regularly are more susceptible to algae growth.
GMW has thousands of kilometres of irrigation channels and it is not possible to test every channel. This year GMW has observed high levels of blue-green algae in multiple channel locations across the region, prompting the water authority to issue a caution for all channels.
Customers are reminded that water supplied by GMW is untreated and is not suitable for drinking or food preparation. Untreated water should also not be used for purposes where skin contact occurs, such as showering and washing.
The open nature of the water storage and supply system means that GMW cannot guarantee any particular quality of water.
“Blue-green algae occur naturally in waterbodies and cannot be removed,” Mr Smith said.
“They may contain toxins that are harmful to humans and animals. Characteristic signs of algae contact are skin rashes or itchiness; sore eyes, ears and nose; or if swallowed, nausea or vomiting.”
Keep up to date with current blue-green algae warnings at
GMW recommends:
  • Do not use channel water for cooking, drinking, washing or showering. Boiling BGA affected water will not make it safe for these purposes.
  • People who come into contact with BGA affected water should wash affected skin immediately in clean cold water.
  • Reading GMW’s fact sheet and other information on blue green algae at GMW’s blue-green algae webpage ( to be informed of the risks.
For more information about blue-green algae and your health, visit or phone NURSE-ON-CALL on 1300 60 60 24.