Sewer - Sewer Contractors
Sonoma County, San Francisco North Bay, Ca. USA 

County Wide Listings

A sewer is an artificial conduit or system of

 conduits used to remove sewage (human liquid waste) and to provide drainage. In the 20th century developed world, sewers are usually pipelines that begin with connecting pipes from buildings to one or more levels of larger underground horizontal mains, which terminate at sewage treatment facilities. Vertical pipes, called manholes, connect the mains to the surface. Sewers are generally gravity powered, though pumps may be used if necessary.

Storm sewers (also storm drains) are large pipes that transport storm water runoff from streets to natural bodies of water, to avoid street flooding. When the two systems are operated separately, the sewer system that is not the set of storm drains is called a sanitary sewer.