For the second time this summer, Gene Coulon Beach in Renton is closed due to high bacteria levels in the water.

According to the King County website, water testing at Gene Coulon Beach — the most southern swimming beach in Lake Washington — shows that bacteria levels are high at 360 bacteria per 100 milliliters of sample water as of Wednesday, Aug. 21. Due to these high bacteria levels, the county says that people — and their dogs — should stay out of the water.

When bacteria results are above 320 bacteria per 100 milliliters of sample water, that is when bacteria levels are considered high. If two of the three bacteria samples (labeled “Sample A”, “Sample B”and “Sample C”) are over the 320 bacteria/100 mL threshold, then the county will recommend the public to not swim in that water.

The water at more than two dozen lake beaches that are popular swimming spots are regularly tested for bacteria every year from mid-May to mid-September. If water tests find high bacteria, it means that there are high levels of poop from people, pets, or wildlife in the water, which can carry germs that make people ill.

Newcastle Beach is also currently closed due to high bacteria levels but for those wishing to swim in south Lake Washington, Kennydale Beach is still open to the public.

What the county does once a beach is closed

The county first tries to find the source of the high bacteria, which means finding the source of poop getting into the water. Additional testing may be utilized along with contacting local sewage utilities about possible sewage leaks and spills.

When the source of the high bacteria levels are determined, the county will work with beach managers to keep poop out of the water, allowing swimmers to eventually return.

According to the county website, beach managers will be advised to do the following:

• Remind people that dogs are not allowed at the swimming beach, and geese and ducks should not be fed near the beach.
• Clean up goose poop from docks to keep it out of the water at the swimming area.
• Reduce the number of geese near the beach, by using shiny mylar strips (“scare tape”) or specially trained dogs.
• Renovate docks to allow more water circulation through the beach area.
• Improve drainage in the park area near the beach, to reduce bacteria washing into the lake near the beach.
• Reduce poop getting into streams near beaches.