Kingborough Council has issued a water quality alert for Blackmans Bay Beach after testing detected elevated pollution levels in the mid section.
The alert, issued on Friday, advises people not to swim at the mid and southern ends of the beach.
“This is likely from contaminated stormwater entering the beach from the catchment above,” the council said.
The northern end of the beach remains “good for swimming”.
Council officers are continuing to monitor water quality, with advisory signage to remain in place until results confirm it meets public health standards.
The warning comes as the southern end of the beach continues to carry a long-term “poor” water quality rating, assigned following the 2023–24 sampling program run by the Derwent Estuary Program.
Three of the beach’s four stormwater outfalls are located at the southern end, carrying runoff from roads and roofs in the surrounding hills.
The mid section, which has a long-term “fair” rating, failed its most recent water quality test on March 20, according to monitoring data.
The council last year engaged Marine Solutions to investigate the impact of stormwater on water quality at the beach, with findings not expected until mid-2026.
As part of the investigation, fluorescein dye has been used to track stormwater movement through the bay, supported by drone monitoring.
Swimmers are advised to check beach signage for the latest updates.
