https://www.invw.org/2022/05/10/how-climate-change-stresses-sewer-systems-in-king-county/

It was dark and stormy — in other words, an April morning in Seattle — and a mixture of untreated stormwater and raw sewage was threatening to flow directly into Salmon Bay, which links Lake Washington and the Puget Sound. 

Over the next 48 hours, rain would overwhelm a network of tunnels under the city designed to treat the wastewater, sending an unsanitary soup of stormwater, chemicals and sewage spewing from an underwater pipe.

The spill would light up King County’s sewer map, an online tool that tracks sewage overflows across the county, effectively marking areas where swimming, fishing and boating should be avoided.

Last year alone, the Puget Sound recorded 220 such spills. On average, these spills collectively dump about 93 million gallons of chemical discharge a year — straight into Puget Sound and its surrounding water bodies.

Utility officials are working to change that, says Marie Fiore, a spokesperson with King County’s Wastewater Treatment Division.