Never dispose of your paints or stains down the storm drain. Either take it to a county collection site or mix it into a solid and dispose of it in the trash.
When painting your house - or anything outside - make sure to pick up any paint chips that may get carried into a nearby storm drain. Rinse all your brushes and tools inside so that the paint doesn't get washed down into the storm drains.
Avoid collecting household hazardous waste by purchasing non-hazardous or the least hazardous products. When using products that contain hazardous materials is unavoidable, make sure to take your leftover hazardous waste to the proper drop-off locations near you.