What causes polluted stormwater runoff?

Polluted stormwater runoff can occur anywhere people are using or altering the land. People going about their daily lives are the number one source of stormwater pollutants, and they are unaware of it. Common examples of people contributing to stormwater pollution include: over fertilizing, excessive pesticide usage, not picking up pet waste, using salt or sand to de-ice driveways, allowing oil to drip out of their vehicles and, of course, littering. If these pollutants are not properly used or picked up, then rainfall or snow melt will wash these pollutants into the storm inlets where they discharge into nearby waterways.