The largest source of stormwater comes from every day human activities. Stormwater travels through structure gutters, along streets, and eventually washes into our waters, picking up everything along the way. The most common forms of pollutants are garbage and toxins. Some examples are:
Garbage - cigarette butts, styrofoam products, food wrappers, etc.
Toxins - motor oil, antifreeze, pesticides, pet waste, etc.
In summary, anything we place on the ground can eventually end up in our water ways, if not intervened or prevented all together.