Stormwater Pollution...The Importance of Infiltration

Clean Water Starts in Your Backyard 
When it Rains, Where Does the Water Go?
What is Stormwater Runoff? 
What is Stormwater Pollution? 


As development occurs, permeable ground such as lawns, farmland, woods, forest or meadow gets covered by impermeable surfaces such as rooftops and pavement. As a result, less water soaks into the ground and more water becomes stormwater runoff. This increased flow of stormwater runoff can carry more pollutants into local waterways and can also cause flooding. Increased imperviousness also reduces the amount of water that seeps into underground water supplies called aquifers. Most Washington County residents get their drinking water from these aquifers. Infiltration is also important because water that soaks into the ground flows underground to discharge from springs into lakes and streams. Water that flows underground to lakes and streams is cooled and filtered in the process. By contrast, stormwater runoff is typically warm and contains pollutants. Thus, more infiltration means cleaner and cooler water in our waterways, and a greater supply of safe and affordable drinking water.

To review, the two factors most important to clean waterways:

   1. Keep pollutants out of the path of stormwater runoff, and
   2. Infiltrate as much water as possible directly into the ground

For More Information:
Regional Natural Resources Program
Basin Education Staff
Department of Natural Resources
University of WI - Extension


What is Stormwater Pollution?  What Can I Do?  Where Does it Go?  Kids Corner