Three popular Lake Washington beaches have been closed to swimmers after water testing revealed dangerous levels of fecal bacteria, with one Renton beach recording contamination nearly 44 times higher than the county’s safety threshold.
Madison Park Beach, Seward Park Beach, and Gene Coulon Memorial Beach Park in Renton are all currently closed to swimming following water samples collected on 11 May. The tests revealed bacteria levels far exceeding the safety limit of 320 Colony Forming Units per 100 millilitres of water at all three locations.
The contamination is most severe at Gene Coulon Memorial Beach, where one sample returned a reading of 14,000 CFUs, nearly 44 times above the county’s baseline for a contaminated beach. Madison Park Beach also recorded significantly elevated levels, with samples ranging from 1,900 to 2,900 CFUs. Seward Park Beach was closed based on samples that similarly exceeded the safety threshold.
High bacteria levels in recreational water typically indicate fecal contamination and can cause a range of illnesses in swimmers, including gastrointestinal sickness, skin infections, and eye and ear irritation. The City of Renton urged residents to stay out of the water entirely. “Do not enter or touch the water, avoid swallowing it, and keep children away from the shoreline,” the city said in a social media statement.
No reopening date has been set for any of the three beaches. Health officials will continue monitoring water quality and will announce when conditions return to safe levels. Elevated bacteria counts at Lake Washington beaches are not uncommon following rainfall, which can wash runoff containing animal waste and other contaminants into the lake.
Residents looking for current test results or alternative swimming locations can visit the King County Public Health website for up-to-date information on beach conditions across the region.
