Stormwater pollution is caused by the daily activities of people everywhere. Rainwater and snowmelt run off into streets, lawns, farms, and construction and industrial sites. While on its way it can pick up fertilizers, dirt, pesticides, oil and grease, and many other pollutants on the way to our rivers, lakes, and coastal waters. Stormwater runoff is our most common cause of water pollution. Because stormwater pollution is caused by so many different activities, traditional regulatory controls will only go so far. Education and outreach are key components to any successful stormwater program.


Because stormwater runoff is generated from dispersed land surfaces-pavements, yards, driveways, and roofs-efforts to control stormwater pollution must consider individual, household, and public behaviors and activities that can generate pollution from these surfaces.

These common individual behaviors have the potential to generate stormwater pollution:

  • Applying lawn-chemicals
  • Changing motor-oil on impervious driveways
  • Disposing of pet-waste
  • Disposing of trash and recyclables
  • Household behaviors like disposing of leftover paint and household chemicals
  • Littering
  • Washing cars

Phase II MS4s

Phase II MS4s are required to educate their community on the pollution potential of common activities, and increase awareness of the direct links between land activities, rainfall-runoff, storm drains, and their local water resources. Most importantly the requirement is to give the public clear guidance on steps and specific actions that they can take to reduce their stormwater pollution-potential.