Stormwater and wastewater (sewage) systems can be built as separate
or combined facilities. The more modern houses and businesses now have
separate piping systems for sewage and stormwater, while some cities are
upgrading their present combined systems due to the occurrences of
spillage of sewage into the environment following a rainstorm. This
spillage can be from overflow at the wastewater plant or from regulators
in the piping system, but both measures involve dumping raw sewage into
the local environment.
This happens because of a combined plant