To stop water pollution it takes all of us working together to stop the water pollution from happening.
Things you can do is to never pour cooking fat or other grease down your drains. Not only will the grease, oil and fat pollute the water it will also clog your drain lines.
Also avoid using chemicals or other harsh cleaning agents that can go down the drain and never pour something not biodegradable down the drain and dispose of all waste properly into a trash can.
If you see trash near a storm drain pick it up and throw it into a trash can and avoid tossing trash onto the street and put it in the trash can.
Never flush medication down the drain and conserve water and avoid using plastic whenever possible