Red flags have gone up over two favorite places to swim for city dwellers, Harku Lake in Tallinn and Anne Kanal in Tartu, which boast among the country's warmest natural water temperatures in any given summer.
The problem at the Anne Kanal was test results from July 29 that exceeded the allowable levels for coliform bacteria.
In the case of Harku, the problem was a type of blue-green algae that can cause contact dermatitis. It was found on July 8.
A follow-up sample was taken from the Anne Kanal on Thursday and the results will be available early next week.
All other beaches and swimming holes around the country currently have a clean bill of health going into what should be a seasonable, summer-like weekend.