Algae Alerts NSW map

The below algal alerts map displays all current alerts collated by the RACCs across NSW. Algal blooms may be present and not reported to the RACCs. This map does not contain data from water storages managed by water supply authorities where there is no public access. Water users should use caution and be aware of signage placed around waterbodies, particularly during the warmer months.

Please click on a site to view additional algal alert details across New South Wales.

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Alerts are declared where algal cell numbers exceed the triggers identified in the Guidelines for Managing Risk in Recreational Waters (1.2MB PDF).

NSW Health advises that any domestic use (including drinking) of surface water without appropriate treatment should be avoided at all times.

NSW Food Authority provides information regarding the impacts of blue-green algae on consumption of food, including all seafood, and within primary production industries.

Additional advisory

There is no additional advisory at the moment.


Alert level definitions


Red alert levels represent 'bloom' conditions. The water may appear green and may have strong, musty or organically polluted 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 drinking (without prior treatment), stock watering, or for recreation.

People should not eat mussels or crayfish from Red Alert warning areas. A precautionary approach should be applied to fishing during bloom events. Any fish caught should be cleaned and washed thoroughly in uncontaminated water and any internal organs disposed of before consumption. Fish fillet meals from algal bloom affected areas should be limited to 1-2 servings per week. Avoiding fishing in a bloom location is the best way to minimise risk, particularly catching and eating fish from locations with severe blooms that last extended periods of time.


At amber alert levels blue-green algae may be multiplying in numbers. The water may have a green tinge and musty or organic 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. The water remains suitable for recreational use, however algal concentrations can change rapidly. Water users should use caution and avoid water where signs of blue-green algae present.


At green alert levels blue-green algae are present in the water at low densities, possibly signalling the early stages of the development of a bloom, or a period where a bloom is declining. At these densities, the blue-green algae do not pose a threat to recreational, stock or domestic use.

For marine and estuarine blooms

The algae guidelines for coastal waters for recreational uses are only based on a few species due to limited knowledge on toxic algae.

A caution alert may also be issued where highly visible blooms elicit public and media inquiries and samples have not been identified or have been identified as non-toxic species.

Algal Information Line

The algal information line on 1800 999 457 provides recorded information on algal alerts. If you have spotted an algae bloom please notify us.

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