When did water pollution start in California?

Water pollution started in California when the first "settlers" started their conquest of the "tribal" or "wandering" peoples.

This "settling" or the way of stagnantly living in one location put undue amounts of human waste in one place near a water source.

Before those settlers, people moved about, giving each environment a chance to heal from the human presence and human by-products of waste and other toxins to the environment.

The end of the wandering way of living in many places- (similar to flowing like water), was the beginning of water pollution in California.