The MS4 is the stormwater drainage system. The MS4 Permit requires the county to prevent polluted stormwater runoff from reaching state waterways through the stormwater system, and to educate the public in ways they can help. Stormwater runoff contains lots of litter. The county recently started a litter cleanup program with homeless shelters whose residents are paid to clean up litter from streets and streams. Shelter residents gain skills and money and the county gains a cleaner environment.