Any substance other than clean rainwater that enters an outside drain is a pollutant, for example detergent from car washing, paint and oil.
Water pollution occurs when these substances leak or spill from their containers, or are poured or washed onto the ground, then enter an outside stormwater drain.
The pollutants that enter outside drains do not get treated 
before they are discharged directly into our beaches, lake or streams.
Every day in North Shore City pollutants enter our waterways. Whether large or small, at home or at work, this results in the pollution of our environment.
Even a very small quantity of pollutant, or just one discharge, can drastically alter the quality of a stream. Fish, insects and plant life can be killed and habitats destroyed.
A polluted stream may never fully recover.
