Undeveloped or grassy (pervious) areas, such as parks and lawns, soak up most of the rain that falls there. Therefore, there is much more polluted stormwater runoff in areas with large amounts of impervious, or non-porous surfaces. Stormwater from urban areas is one type of 'nonpoint source' pollution - pollution that comes from many diffuse sources. The stormwater picks up all the pollutants along its pathway. It is often referred to as “Polluted Runoff.” Because polluted stormwater runoff is caused by so many of our everyday activities, we all need to work together to prevent it!