Swimming, diving, fishing and other recreational activities can recommence at Lake Alexandrina including the Goolwa channel, following latest water tests.
Pets can also safely swim in the water, and fish caught in the lake are safe to eat.
The green light comes four months after toxic blue green algae blooms were first detected in the lake.
Water samples now show blue green algae is no longer present, following heavy winter rains.
SA Water does not source water from the lake and has confirmed that water it supplies from other sources to the area is safe to drink.
Routine weekly testing of the lake will continue.
Water quality alerts and information about the health effects of blue green algae can be found on the SA Health Water quality alerts page.
Quotes attributable to SA Health Principal Water Quality Adviser, Dr David Cunliffe.
Recent testing of water quality at Lake Alexandrina has shown there is no longer a presence of a bluegreen algae bloom.
This is positive news as the lake is a popular venue for recreational activities and, as temperatures riseas we head toward spring, the number of people using the lake for recreational purposes will increase.