If you were hoping to cool off at some of King County’s favorite lakes, you might want to pump the brakes. Five busy swim beaches are under advisory after water tests showed bacteria levels well above what the county considers safe.
Health officials are urging people to stay out of the water at Gene Coulon Memorial, Juanita, Lake Meridian, Matthews, and Waverly beaches while they run follow-up tests.
High Readings at Five Popular Swim Areas
Routine samples collected on June 15 turned up multiple high readings at each of the five sites, triggering the warnings. As reported by MyNorthwest, Waverly had a sample measuring 750 CFU per 100 mL, Gene Coulon 670 CFU, Lake Meridian 630 CFU, Matthews Beach 590 CFU, and Juanita 400 CFU.
According to Public Health – Seattle & King County, the county generally recommends that swimmers stay out of the water when two or three samples on the same day top 320 CFU per 100 mL.
What the County Warns Swimmers
"We test the water for bacteria, which tells us whether there is poop in the water from people, pets, or wildlife," Public Health – Seattle & King County wrote, noting that germs from poop can cause rashes, stomach illness, and other infections.
The agency collects three samples from different parts of each beach to pinpoint possible contamination and decide whether to recommend closures. Park crews have posted signs at the affected swim areas and will wait for follow-up test results before lifting any advisories.
Heat, Crowds and Runoff
Warm, sunny weather has packed shorelines with swimmers and pets, raising the odds that people and animals track waste into the water. MyNorthwest reported daytime highs in the 80s and 90s across parts of the region during the testing period, which keeps beaches busy and increases the chance that several polluted samples will show up at once.
Public health officials add that bacteria often come from people, pets, or wildlife and can linger in shallow, warm water until currents, time, and dilution help disperse recent contamination.
Where to Swim Instead
Not every public swim area is affected. Many lifeguarded beaches remain open and are still being monitored. City pages and prior coverage, including bacteria scare shuts down three, list Madrona, Magnuson, Meydenbauer, and Luther Burbank among the swim areas that have not been flagged while investigators test other sites.
Before you head out, check park webpages for posted closure signs and lifeguard updates.
A few simple moves can lower your risk: do not swallow lake water, keep children and pets away from scummy shorelines, and shower after a day at the lake. If you end up with stomach trouble, ear infections, or skin problems after swimming, contact your doctor and let them know exactly where you were in the water.
