Blue-green algae

A photo of Lake Weeroona at night illuminated by street and footpath lighting

We monitor our urban lakes for blue green algae regularly. Blue-green algae occur naturally and can be dangerous to humans and animals. Characteristic signs of algae contact are skin rashes or itchiness; sore eyes, ears and nose or, if swallowed, nausea and vomiting.

Blue-green algae can be present in water where there are no obvious signs of a problem. Visual inspections of the water cannot be relied upon to determine the presence of algae levels. 

Current blue-green algae alerts

To view alerts in the area, go to Goulburn Murray Water website: Blue-green algae warnings and public alerts.

During alerts

If there are active alerts, boating, fishing, sightseeing and other activities that do not involve direct water contact can still be enjoyed at the lakes. If you go near or come into contact with the affected water, wash the affected skin immediately in clean water.

Alert levels explained


This alert level represents 'bloom' conditions. The water may appear green and may have strong, musty odours. Blue-green algae may be visible as clumps or as scums. The 'blooms' should be considered to be toxic to humans and animals, and the water should not be used for potable water supply (without prior treatment), stock watering, or for recreation.


Blue-green algae may be multiplying in numbers. The water may have a green tinge and musty or organic taste and odour. The water should be considered as unsuitable for potable use and alternative supplies or prior treatment of raw water for domestic purposes should be considered. The water may also be unsuitable for stock watering. Caution should be exhibited to avoid skin contact and ingestion if using the water body for recreation.


Blue-green algae are first detected in the water at low amounts, possibly signalling the early stages of the development of a bloom. At these concentrations, the blue-green algae do not pose a threat to recreational, stock or domestic use.

Contact us

For more information about environmental health please contact our office on 1300 002 642 or [email protected]

More information

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