There's no problem with washing your car. It's just how and where you do it. Most soap contains phosphates and other chemicals that harm fish and water quality. The soap, together with the dirt, metal, oil and other automotive fluids washed from you car, flows into nearby storm drains. These storm drains flow directly into our stormwater ponds, ditches and the Straight River.
The phosphates from the soap can cause excess algae to grow. Algae look bad, smell bad, and harm water quality. As algae die, the blooms sink to the bottom and decompose. During this processes oxygen is removed from the water. Fish and other aquatic life can not exist in water with low dissolved oxygen levels.