River and Slough Flooding in Marysville, WA

Most Marysville homes sit on ground higher than the delta and the river valleys, but the low land along Ebey Slough and the Snohomish River delta is a different story. Downtown sits at about 5 feet above sea level on the banks of the slough, and the farmland and sloughs south of town are low and silty. In December 2025 an atmospheric river pushed the Snohomish River to a record crest of about 34.15 feet at the Snohomish gauge on December 12, topping the 1990 record. Snohomish County had issued an emergency flood proclamation on December 9, dikes around Ebey Island were expected to overtop, and in Marysville the city closed 152nd Street NE and the Ebey Waterfront Trail and Park.

River water brings mud and contaminants, and the clock starts as soon as it touches the home. In the first hour, it soaks carpet, pad, drywall and insulation and leaves silt in every corner. By 24 hours, drywall has wicked water well above the flood line and wood flooring begins to swell. By 48 hours, mold can start on wet drywall paper and framing, and the odor grows. After a week, cabinets, flooring and walls that sat wet usually need full replacement, and cleanup becomes slower and more expensive.

River and slough water is category 3 water, so far less can be dried in place than after a clean pipe leak. The parts that usually stay are the structure itself: wall studs, floor joists, concrete slabs, foundation walls and solid wood subfloor. Those are cleaned, scrubbed and disinfected first, then dried with dehumidifiers and air movers until readings reach dry targets. Solid wood doors and some trim can be cleaned and dried if they did not swell. Metal, glass and hard plastic items can usually be cleaned and kept.

Most porous materials that touched river water are removed. Carpet and pad are almost always replaced, because the pad soaks up contaminated water and cannot be cleaned. Drywall is flood cut a foot or more above the highest wicking point, and the insulation behind it comes out. Laminate, engineered wood and vinyl plank with a fiberboard core usually swell and are replaced. Particleboard cabinet bases, upholstered furniture, mattresses and soaked boxes are generally discarded, because silt and sewage soak deep into them and odors stay even after drying.

In Marysville, river and slough flooding is a concern mostly on the lowest ground. Older homes and businesses around downtown sit near Ebey Slough, and the area along the slough near Sunnyside and the Qwuloolt Estuary, where a levee was breached in 2015 to return tidal water to former wetland, is low and wet. During the December 2025 flood the city closed 152nd Street NE between Strawberry Fields Athletic Center and 67th Avenue and warned drivers about ponding, which shows how water collects on the flats. Homes on higher ground in Getchell and Whiskey Ridge rarely see river water.

The bigger river risk is north along the Stillaguamish. The river set a record crest of 21.34 feet at the Arlington gauge on December 5, 2023, and at 19 feet the county expects major flooding in Silvana, Norman, Florence and Stanwood. Much of downtown Stanwood sits behind dikes in a 100-year flood zone, and in Arlington the 2023 crest submerged Twin Rivers Park. One call connects you with a local crew that can start cleanup once the area is open.