After the Rain, Stay Out of the Thea Foss Waterway

If a fall paddle on the Thea Foss Waterway is on your calendar, recent rainfall should be part of your planning. The Tacoma-Pierce County Health Department has issued a seasonal advisory recommending that people avoid contact with the water for 48 hours after it rains. The advisory, posted October 5 and still listed among the department’s current warnings, applies from the 11th Street bridge to the south end of the waterway.

The concern is what rain carries into the water. Runoff can wash bacteria into the Thea Foss, increasing the risk of illnesses that cause nausea, vomiting and diarrhea. The department specifically includes kayaking and paddleboarding among the activities to avoid during that window. Its recommendation extends beyond swimming, so staying aboard a small watercraft doesn’t put an outing outside the warning.

The timing matters even when the weather improves. A sunny afternoon following a wet morning still falls within the advised waiting period. For anyone choosing a day to launch, the relevant question is when it last rained—not simply whether the forecast looks pleasant when they leave home. While this seasonal advisory is in effect, the department recommends avoiding water contact for the full 48 hours after rainfall.

There is another reason to be cautious about treating that window as permission to jump back in. The Washington Department of Ecology also lists the Thea Foss Waterway among locations with long-term or permanent advisories against water-contact recreation. Its guidance is to avoid touching the water when possible. The local rainfall warning therefore deserves attention alongside that broader advice; waiting two days does not establish that the water is safe.

Before planning an outing, check the Health Department’s current surface water advisories and read its Thea Foss rainfall notice. Questions or concerns about possible illness after water exposure can be directed to [email protected] or 253-649-1420. The department advises seeking medical care if symptoms are severe or persist beyond a few days.