Sanitary sewer service in Port Costa was for a long time provided by Sanitation District #5 of Contra Costa County ("SD-5"), which was run by the County Public Works Dept. The Port Costa treatment plant was built in 1984 to serve the tiny community. Following the formation of Crockett Community Services District in 2006, a Port Costa Sanitary Commission was appointed by the District Board to oversee transfer of the sewage facilities to a new Port Costa Sanitary Department. That department assumed operational control of the Port Costa wastewater treatment plant and sewer system in June 2008.

Development in Port Costa is constrained by the Carquinez Strait to the north and the hilly topography and unstable soils of territory in the other directions, most of which is now owned by the Port Costa Conservation Society or the East Bay Regional Park District and thereby removed from consideration for development. The Port Costa Sanitary Dept. foresees very limited infill growth and anticipates no need for expansion of its facilities.