Water quality alerts

SA Water routinely monitors the quality of several public water resources for microbiological (eg blue green algae, E. coli, protozoa) and chemical levels and provides results to SA Health. Health advice will be issued when there is a health risk to the public.

Blue green algae (cyanobacteria) can build up in fresh water, which can sometimes cause bright coloured surface scums or algae ‘blooms’ to form. Some blue green algae produce toxins which can be harmful to humans and animals.

Not all water sources in South Australia are tested for water quality.

Avoid contact with fresh water (eg rivers, lakes, creeks, dams) if it has scum or a coloured film on the surface.

Do not drink water unless you know it is safe. Untreated water can cause gastroenteritis including diarrhoea, vomiting and nausea.

Current water quality alerts

Lake Bonney advice – 2 February 2023

Lake Bonney blue green algae readings on 1 February 2023 were all below the recreational water guidelines.

People who wish to swim and dive can continue to do so but should avoid areas where there is visible blue-green water discolouration.

The levels of blue green algae at Lake Bonney can change from day to day and may increase with warmer weather. Algal blooms can move around the lake in response to changing weather conditions.

The connection of the Lake to the River Murray is expected to reduce the levels of blue green algae.

Regular testing of blue green algae levels is being carried out and these results are being published on this page, allowing people to determine where and when to swim.

Check this page regularly for updates. The situation is variable and subject to change.

Avoid swallowing large amounts of water. Fish caught in the lake should be cleaned and gutted thoroughly before being eaten.

Algal blooms are naturally occurring, and appear during low rainfall, low water flows, and warm weather conditions. 

Preventing illness

If you suspect contamination of water with blue green algae:

  • do not use the water for any purpose including drinking, cooking, washing or showering (boiling the water will NOT make it safe to drink)
  • do not consume shellfish sourced from the water
  • do not let pets and livestock bathe in or drink contaminated water (particular care should be taken with dogs as they can ingest very high concentrations of organisms from grooming their coat after contact)
  • if irrigation with water contaminated with blue green algae is unavoidable, do not use contaminated water directly on plants being grown for human consumption.

Health effects of blue green algae

Direct contact with the algae affected water may cause irritation to the skin, eyes, ears, nose and mouth. If you experience irritation, wash the area with clean water.

If you have swallowed large amounts of algae affected water, you may develop symptoms including:

  • nausea
  • diarrhoea
  • vomiting
  • abdominal cramps.

Contact your GP if symptoms develop and let them know you may have been exposed to blue green algae.

Monitoring water quality

SA Water routinely monitors water quality from sites along the River Murray as part of ensuring safe drinking water. Results are also used to inform the community about water quality safety for domestic use (laundry, irrigation, bathroom etc) and recreational activities.

See the SA Water – water quality testing locations (PDF 106KB) to see where testing is regularly done.

Testing frequency

  • E. Coli - weekly to monthly, depending on location.
  • Cyanobacteria - weekly.
  • Chemicals - weekly to monthly, depending on location.

Testing other sources

SA Health and SA Water may test other water sources not listed above, and testing frequency will increase if there is a public health concern.

During the 2022/23 River Murray flood event, testing is also being undertaken at:

  • Lake Bonney (Barmera Riverland)
  • Southern Fleurieu beaches (River Murray mouth).


Blackwater in the River Murray poses no direct public health risk. In a small number of people, blackwater may cause a skin irritation due to sensitivity to natural organic matter in the water.

It is recommended not to drink water from the River Murray at any time unless it is treated.

For more information, see Blackwater on the Department for Environment and Water website.

More information