The first sanitary sewer system construction began in the early 1900's in the Flat Branch headwater area, a tributary of Hinkson Creek. Prior to 1950, the sewer system included areas in County House Branch of Hinkson Creek. Around 1960, sewers were extended north along Hinkson creek and sewer systems were constructed in the drainage areas of Bear Creek and tributaries of Perche Creek. During the 1970's and 80's numerous trunk sewers were constructed, including major lines that parallel the Hinkson, Bear and Perche Creeks which serve as influent sewers to the Columbia Regional Wastewater Treatment Plant, constructed from 1980 to 1982. Sewer extension and trunk sewer construction has continued into the 2000's and the City's collection system, which extends beyond the city limits, consists of approximately 635 miles of sewer main lines and 16,000 manholes.
The Sanitary Sewer Maintenance Section is responsible for the maintenance and repair of all public sewer mains and manholes. The service lines from houses and businesses to the main, including the connection at the main, are the responsibility of the property owners. The purpose of the Sanitary Sewer Maintenance Section is to ensure the efficient and sanitary movement of wastewater to the Wastewater Treatment Facility.