Plumlov Reservoir water deemed safe for swimming despite downgraded quality rating

The Olomouc regional health authority conducted its scheduled water‑quality sampling at Plumlov Reservoir on 20 July. Laboratory analysis lowered the visual rating from the highest (blue smiley) to the second level (green smiley) because water transparency fell from 1.0 m to 0.6 m and chlorophyll‑a concentrations increased. Despite these changes, the water remains free of health hazards, with cyanobacterial counts still within safe limits. Officials advise bathers to shower after swimming.

Sampling will continue fortnightly at the U Vrbiček beach, with an extra check on 3 August that will also include the nearby Poděbrady sand‑gravel lakes. The increased monitoring frequency reflects recurring cyanobacteria occurrences and ongoing phosphorus‑laden runoff despite recent wastewater‑treatment upgrades. In the previous season a temporary swimming ban was imposed when water quality deteriorated early in summer, but this year the reservoir is still classified as suitable for recreational use.