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Blue-green algae status and swimming water quality
The quality of swimming water is monitored throughout the swimming season.
See the blue-green algae status on the Outdoor Exercise Map service (summer season)(Link leads to external service)(Link leads to external service)
Check from the sampling plan 2023 (pdf) when the water will be sampled and at which beaches.
Why are beaches subject to swimming restrictions?
In 2023, the Helsinki Environmental Services recommended that people do not swim at the Iso Kallahti, Marjaniemi and Rastila beaches, because their water quality has been determined to be poor based on the sample results. Water samples taken at the beaches have from time to time contained elevated amounts of intestinal bacteria.
Based on the swimming water sample results, the swimming water quality at Iso Kallahti, Marjaniemi, Rastila and Pikkukoski beaches has been classified as poor in 2023. The classification is based on the logarithmic average of the sample results from the previous four swimming seasons. If the swimming water is classified as poor, the municipal health protection authority must give instructions to avoid swimming, or swimming must be prohibited at the beach in question, either temporarily or permanently, for at least one bathing season.
The municipal health protection authority assesses and classifies the swimming water quality at each beach on the basis of the results of controls after the end of the swimming season. The classification is made only for public beaches (so-called EU beaches) where beach users are estimated to be at least 100 per day during the swimming season. The classification is not made for small public beaches.