The below advice applies to SA Water customers who receive non-drinking water from the Mannum to Adelaide and Murray Bridge to Onkaparinga pipelines, and customers who receive drinking water in lower Riverland towns.
Blackwater is a natural phenomenon. It can occur after heavy rainfall, when organic material such as leaves and wood from floodplains washes into waterways. This results in low dissolved oxygen levels. The water is blackish in appearance and has a strong unpleasant smell.
A blackwater event is moving through South Australia and is affecting areas of the River Murray. It's been generated by significant high flows onto the floodplain upstream of South Australia.
For more information, visit the Department of Environment, Water and Natural Resources (DEWNR) website.
Our water treatment plants are designed to treat a range of water qualities.
We are closely monitoring the current event from a drinking water quality perspective. As required, we are modifying processes at our water treatment plants which take water directly from the river.
Treatment processes at our plants have been adjusted to deal with any potential water quality issues.
We also have a comprehensive routine monitoring and testing program in place for all drinking water supply systems.
The water quality challenges presented by blackwater can be effectively treated via SA Water’s treatment processes. They therefore do not currently pose a drinking water quality issue.
We are in constant contact with SA Health on the issue. All our water supplies are tested regularly to ensure they comply with the Australian Drinking Water Guidelines.
While the blackwater event moved through the River Murray, water treatment processes were adjusted to deal with the increased organic matter in the raw water.
Water is disinfected with chlorine to destroy any microorganisms and ensure it is safe to drink.
Trihalomethane (THM) is a by-product of chlorine disinfection, which is created by the interaction of chlorine and organic matter. THM levels are monitored to ensure compliance with the Australian Drinking Water Guidelines and are reported to SA Health. Short-term increases don’t pose any risk to human health and maintaining appropriate disinfection to ensure the safety of drinking water takes priority.
As a result of the increased organic matter, levels of THM temporarily increased in water sourced from the River Murray. These decreased as the blackwater moved through the river and the raw water quality improved.
Some customers may have also noticed temporary changes in the taste and odour of their water .
In all instances associated with the blackwater event, SA Health confirmed the water remained safe to drink.