Polluted stormwater runoff is one of the biggest water pollution threats in the Northwest. Stormwater sweeps across pavement, collecting contaminants: motor oil, pesticides, pet and livestock waste, and trash. Then it travels through pipes and storm drains, dumping this pollution soup straight into lakes, rivers, and Puget Sound.

This pollution impacts our environment, economy, and health. Despite a network of drainage systems, flooding in denser communities is still a problem. During heavy rains, flooding can close roads and damage property, or incapacitate public utilities. Pollution from stormwater, and sewage overflows in some areas, close swimming beaches and make it unsafe to catch and eat local fish and shellfish.

Pollution disproportionately impacts communities of color, low-income communities, and indigenous communities. It’s vital to include all community voices in planning decisions and to build solutions that protect everyone from the damage caused by pollution and urban floods.

Polluted stormwater also endangers the other creatures that call this place home. Stormwater runoff from a major arterial road can kill adult coho salmon in as little as three hours, and in many urban creeks more than half of returning salmon die before they can reproduce because of contamination from stormwater runoff. (Read more about salmon and stormwater.)

Channeling stormwater through pipes and outfalls also impacts our communities during the dry season. When stormwater filters into the ground, it recharges groundwater reserves that keep small streams running when there’s no rainfall. If we don’t allow the water to soak in, some streams could dry up in the summer when groundwater reserves don’t recharge, even depleting drinking water supplies.