What is stormwater, and how is it polluted?
Stormwater runoff is the rain that hits the ground and flows off rooftops, lawns, parking lots and streets. As it makes its way across these surfaces, it picks up contaminants such as oil and grease, pet waste, fertilizer and pesticides, dirt and anything else that is on the ground.
Stomwater is then collected by storm drains and roadside ditches where they flow into the nearest surface waterbody along with any pollutants. In Cowlitz County, this could be a flood protection waterway, stream, river, pond or lake.
What are the sources of these pollutants?
We are all part of the stormwater pollution problem. Many of the things that we do daily--such as taking care of our lawns, driving our cars, washing our vehicles and walking our pets--can all contribute to water pollution.
Click on the graphic to the right to see how rain turns into runoff and some of the common sources of stormwater pollution in our community.
Isn't stormwater treated?
A common misconception is that water running into a storm drain on the
street goes to a wastewater treatment plant. It does not, and in fact stormwater usually receives no treatment
before it flows into a river, lake or stream.
Sources of Stormwater Pollution
(click to enlarge)
What can I do?
Go to the Solutions page to find out how you can be a "solution to stormwater pollution" and keep Cowlitz County's waters clean and healthier for both people and the environment!