Question: About 8:30 a.m. on June 15, my husband and I witnessed something pouring off the Tacoma Narrows Bridge.
It was a steady column of gray fluid that, from our home on Salmon Beach, looked like it was about 20 feet across. It went on for about 15 minutes. We’ve lived here 39 years and have never seen anything like it. What was it?
Susan Maxwell, Salmon Beach
Answer: According to the state Department of Transportation, it was wash water.
Bridge maintenance crews use fresh water to rinse salt off the eastbound bridge once a year. Bridge engineers say removing accumulated salts helps fight corrosion, which will make the bridge last longer.
Spokeswoman Claudia Bingham Baker said the Transportation Department has a state permit for the discharge into the Narrows.
“The entire length of the 2007 bridge deck and steel substructure under the deck are rinsed annually with fresh water to remove salts that accumulate from the sea water below,” Bingham Baker said.
“Crews use a water line that was permanently installed on the bridge when it was built. The water line has numerous valves that allow crews to rinse segments of the bridge at a time.”