The river gets contaminated mostly the urban runoff, trash blown away by the wind, or plastic that people just leave everywhere. Runoff can also include chemical contaminants from fertilizers, pesticides, motor oil, and other things that get washed into storm drains when it rains. Many places get most of their pollution during the rainy season. Though on most days the beaches and coastlines are in excellent condition, it is not quite perfect. While it is not as bad as Los Angeles or Orange County, where 1.5 million people get sick each year, there are a lot of places that are not the healthiest for people. 11th grade students on the Davidson-Scherer team from High Tech High Media Arts tested the waters of many areas, including the San Diego Rivermouth and a site at Fashion Valley, which is along the river. They found on October 12, the San Diego Rivermouth nearly exceeded the Environmental Protection Agency (EPA) standards for E. coli levels but on November 2 it actually did. And on October 27 the total coliforms level at Fashion valley exceeded the EPA standards.