Charleston Water System's Engineering and Construction Department manages our Capital Improvement Program.

Staff engineers are responsible for designing new projects such as water and sewer main extensions and replacement of plant infrastructure. The engineering and construction staff also manages water and sewer requests for new construction, and requires developers to meet specifications for water and sewer main construction.

The Engineering Department also maintains Charleston Water's Geographical Information System (GIS) and administers the Cross Connection Control Program.

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Specifications for Developers and Contractors

Sewer Tunnel Replacement Project

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The administration building at Charleston Water System's Hanahan Water Treatment Plant.

The Hanahan Water Treatment Plant is the largest treatment plant in the state, providing the Greater Charleston area with clean, safe drinking water.

The plant is located on a 60-acre site on the banks of the Goose Creek Reservoir in Hanahan, which served as Charleston Water System's primary source of raw drinking water for most of the 1900s.

The plant now treats water from the Bushy Park Reservoir and the Edisto River. Built in 1902, the plant has been upgraded with new technology and equipment, but the original pump buildings still house plant operations.

The Hanahan Water Treatment Plant has earned numerous awards for excellence, and is a member of the Partnership for Safe Water.

The plant has a permitted capacity to produce 118 million gallons per
day (mgd), but averages 58 mgd.

The laboratory staff at the treatment plant tests more than 4,000 samples
each month, including samples from raw water sources, treated
water at the plant, and water in the distribution system to ensure
water quality.

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Water treatment process schematic

Water Quality

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The sedimentation basins allow the heaving particles of impurities settle out of the water.

Charleston Water System's DHEC-certified laboratory runs thousands of samples each year to ensure our water is safe to drink.

A crew opens a fire hydrant to flush a water main.

Once treated, drinking water enters the Water Distribution System,
which consists of 1,750 miles of water mains.

The mains, storage tanks, and pump stations in the distribution system deliver clean water to thousands of homes and businesses in the greater Charleston area. Charleston Water System also owns and maintains more than 8,875 fire hydrants, which not only provide fire protection, but are also used to flush water mains.

Water distribution crews are responsible for maintaining water lines
and completing minor extensions. Crews constantly flush water lines
to clear pipes of mineral deposits and test valves to ensure lines can
be isolated in the event of a main break or loss of system pressure.
After the installation of a new line or repair of an existing line, the pipe
is disinfected and flushed clean.

Related links

Water treatment process schematic

Water Quality

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Water rates

FAQ

History

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An crews prepares to inspect a sewer line using video camera technology.

When wastewater leaves your home, it enters Charleston Water System's Wastewater Collection System, a network of pipes, pump stations, and tunnels that carry sewage to the Plum Island Wastewater Treatment Plant.

The collection system consists of 540 miles of gravity sewer mains, 115 miles of force main, 187 lift (pump) stations, 15 vortexes, and more than 8,800 manholes. Although the system dates back to the late 1880's, Charleston Water System has been operating and maintaining the system since the late 1960's.

The Wastewater Collection Department inspects and maintains sewer lines and pump stations using vactor trucks (large vacuum trucks) and TV trucks (equipped with robotic cameras) to inspect and clean sewer manholes and mains. The department's construction crews perform repairs and replacements of mains, force mains, service laterals, and manholes.

The department also inspects grease traps for commercial food establishments, which prevents grease clogs in sewer lines.

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Wastewater treatment schematic

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Inspecting a sewer line in the "TV truck."

The vactor truck, used to clean out sewer manholes.

Wastewater arrives at the Plum Island treatment plant, where multiple processes remove debris, pollutants, and harmful microorganisms from the water before releasing it into the Charleston Harbor. Wastewater treatment plays a critical role in protecting public health and the environment.

Built in 1971, Plum Island is located off of Harborview Road on James Island. It has a permitted treatment capacity of 36 million gallons per day (mgd), but treats an average of 19 mgd.

Despite an increase in customer accounts, wastewater flow into the plant has actually decreased over time as a result of systematic efforts to remove sources of storm water inflow into the wastewater collection system. Regular inspection of sewer lines with robotic cameras and smoke testing identifies pipe deficiencies and cross connections with storm water lines. Eliminating this extraneous flow helps prevent sewer system overflows during heavy rain events, when storm water can overwhelm pipe capacity. It also prevents storm water from taking up valuable capacity at the treatment plant.

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Wastewater treatment

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The Daniel Island Wastewater Treatment plant provides pre-treatment for wastewater collected on Daniel Island, Thomas Island, and the Cainhoy Peninsula. After pre-treatment, wastewater flows through a deep tunnel to the Plum Island plant.

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