1. Fresno, California
2. Bakersfield, California
3. Philadelphia, Pennsylvania
4. Bridgeport, Conn.
5. Modesto, California
6. Riverside, California
7. New Haven, Connecticut
8. San Jose, California
9. Stockton, California
10. Milwaukee, Wisconsin
See the rest of the top 20 dirtiest cities on Forbes.com
Photo by Flodigrip’s world