In order to protect public health and safety, the City of Prior Lake monitors both of our public beaches (Sand Point Beach and Watzl’s Beach at Lakefront Park) for E. coli levels in accordance with Minnesota Rule 7050.0222. The City’s beach testing policy includes:
- Weekly water samples collected at both sites
- A beach will be closed if E. coli levels exceed 126 MPN/100 ml as a geometric mean of the last 5 samples
- A beach will be closed if E. coli levels exceed 235 MPN/100 ml for a single sample
- A beach may only be reopened when E. coli levels fall below 100 MPN/100 ml as a result of further testing
Sand Point Beach is currently CLOSED for swimming. Sand Point Beach was immediately closed on August 12 after the City received test results from two August 11 samples averaging over 400 MPN/100 ml. The City will retest the water and should receive results by Friday, August 14. If the test results indicate a low level of E. coli in the water, Sand Point Beach may be reopened on Friday, August 14. If test results indicate that high levels of E. coli are still present, the beach will remain closed until subsequent tests show acceptable levels.
Watzl’s Beach was previously closed from July 29 to July 30 based on water samples that exceeded the single sample E. coli limit. The City retested the water at Watzl’s Beach on July 30 and received the results on July 31. The test results indicated a low level of E. coli in the water and Watzl’s Beach was reopened on July 31. Subsequent tests have indicated low levels of E. coli in the water. Watzl’s Beach is currently OPEN for swimming.
It is not known what caused the temporarily elevated E. coli levels at Watzl’s Beach and Sand Point Beach. Testing for specific disease-producing or pathogenic organisms is difficult, expensive, and time-consuming. Therefore, E. coli is used as an “indicator organism”, providing an indication of the possible presence of other pathogens. E. coli in lakes originates from animal waste (including humans, pets, livestock, and wildlife). E. coli bacteria themselves are not usually harmful but can be associated with other disease-causing bacteria or parasites. Swimmer’s itch is not caused by E. coli but is often found in areas with elevated E. coli levels.
Beach patrons can reduce their impact on beach water quality by leaving their pets at home and by not feeding the ducks and geese that frequent the beach areas.
The City will continue to test public beaches in accordance with our policy. Please contact Pete Young, Water Resources Engineer, at 952-447-9831 for more information about the testing program or lake water quality. For more information about E. coli and general beach safety, please visit: