The dates of the Great Swim events have been chosen to avoid any peak periods in blue-green algae and we will be monitoring the water quality in the lead up to the event.


Blue-green algae is naturally occurring in lakes, ponds, reservoirs, rivers and the sea. These commonly occur during periods of prolonged hot weather in calm waters - such as near to the water’s edge or shoreline.


At most levels this algae poses no threat to swimmers. It is only on the rare occasions when the algae reaches extremely high levels that it can form a scum and produce toxic substances. Great Swim monitors the water quality and we would carry out our contingency plans if there are any scums on the water.