When it rains or water flows out of yards or over pavements, the water (along with all the surface dirt, grime and oil) flows directly into storm drains. There is a great misconception that this water gets “cleaned” before reaching waterways. Sewer systems and storm water conveyance systems (drains, inlets and catch basins) are in fact separate. While the sewer water gets treated, everything else that washes into the storm water conveyance system is left untreated, and flows directly into our rivers, creeks, bays and ocean.