The contents of the gravity main flow to a lift station which pumps the wastewater into a force main. Under pressure, the sewage is conveyed to the treatment plant. The system is constructed to protect the public health by preventing untreated sewage from leaking out into the environment. Unlike the sanitary sewer system, the stormwater sewer system is an open system designed to collect water and prevent flooding. Grates, gutters and outfalls in the roads convey rainfall to large gravity pipes which eventually lead to a wet retention area, canal, lake or other surface water body.
Some municipalities do use pumps in low lying areas to move standing water and prevent flooding.
Both of these systems are designed for a specific purpose, are meant to be kept separate, and will not to function properly if foreign objects are introduced. Occasionally, homeowners sewage pipes are illegally connected to the stormwater system. This leads to pollution of our waterways. Never dispose of debris or chemicals down your home drains. Likewise never dump or dispose of anything down a storm drain as it is against the County Code to discharge into waters of the County.