What can I put in the storm drain?

No chemicals of any kind should ever be put into the storm drain system, including gutters, catch basins, ditches, creeks, etc.! When someone does dispose of harmful items (gasoline, oil, antifreeze, paint products, pesticides, herbicides, etc.), they open themselves up to criminal prosecution, as well as a civil action obligating them for the cost of the cleanup. This will include all areas that it may affect downstream.