Seattle beach bacteria spike closes 5 King County parks

RENTON, Wash. - As temperatures climb into the mid-80s and 90s across western Washington, crowds are flocking to lakes and beaches for relief. However, five King County swim beaches are currently closed due to high bacteria levels.

One of the closures is Gene Coulon Memorial Beach Park in Renton. Despite warning signs, some beachgoers are ignoring the orders and entering the water.

What is Causing the Closures?

Testing shows the elevated bacteria levels are directly linked to goose poop. King County tests the water weekly during the summer. While they test for a general indicator bacteria found in all warm-blooded animals, historical winter testing points squarely at local wildlife.

Ecologist Daniel Nitskorski explained the results saying, "What we found is that it’s very rare that we can detect poop from people or from dogs, and it’s very, very common to find moderate to high levels of poop from geese when a beach is closed... we're really confident that goose poop is by far the main cause of closures when a swimming beach gets closed due to poop in the water."

Health Risks: What Happens If You Swim?

Public health officials recommend closing a beach when the data suggests roughly 3% to 5% of swimmers could get sick. While the risks are rarely severe or life-threatening, ignoring the signs can ruin your summer week.

"It’s not going to be a rampant everyone end up in the hospital kind of a thing," Nitskorski said. "What we’re mostly talking about are tummy bugs, nausea, vomiting, diarrhea. Sometimes rashes or skin problems can come from these germs, and so people do have to make some of those decisions, you know?"

How the Data Triggers a Closure

The county takes three separate water samples across each beach to ensure accuracy.

"It's basically if two or three of those samples are high above 320 bacteria per 100 milliliters of water, that's when they'll say it's too high. Bacteria can be really variable from one sample to the next. That's why we take three samples across the swimming beach, so we're not just basing that on one little dip of water that was at a random fleck of goose poop in the bottle."

Where to Cool Off Safely

While five beaches are out of commission, 25 other monitored beaches remain open with excellent water quality.

Check Before You Go:

Residents are urged to check live, up-to-date maps and green dots at kingcounty.gov/swimbeach. The site updates every Tuesday and Wednesday afternoon as new weekly data rolls in.

Beware of Cold Water Shock:

Even on 90-degree days, local waters can still be below 70°F (21°C). Officials advise entering the water slowly rather than diving straight in to avoid cold water shock.

How You Can Help

Experts say the public plays a direct role in keeping these community spaces open. Do not feed the ducks or geese. Feeding them keeps them gathered at the shorelines, leading to heavy accumulation of bacteria-laden poop, which ultimately forces the city to close the beaches to protect public health.

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