What We Do

Charleston Water System is a public water and wastewater utility. We provide clean water services to the Greater Charleston Community.

Formally known as the Commissioners of Public Works of the City of Charleston, SC, we are an independent utility governed by an elected Board of Commissioners. Our 430 associates protect public health and the environment of our community by providing high quality, reliable water and sewer services.

Our Hanahan Water Treatment Plant produces high quality drinking water that's delivered to our customers through 1,800 miles of water mains. The Hanahan Plant meets or exceeds all regulatory requirements and is a member of the Partnership for Safe Water.

We also provide sewer service—not stormwater—through 700 miles of collection mains, 187 pump stations, and eight miles of deep tunnels that carry wastewater to our treatment plant. The Plum Island Wastewater Treatment Plant treats an average of 19 million gallons a day and releases clean water into the Charleston Harbor.

CWS is committed to preventing pollution and improving the environment. We have implemented an environmental management system (EMS) and are certified under ISO 14001, the international standard for environmental management.

Have a question, need information, or want to provide feedback? Contact us.

View of the Charleston Harbor from our Plum Island Wastewater Treatment Plant

View of the Charleston Harbor from the Plum Island Wastewater Treatment Plant

Sedimentation basins at the Hanahan Water Treatment Plant

Sedimentation basins at the Hanahan Water Treatment Plant
Looking for another agency?
Charleston Water System provides public water and sanitary sewer service only. For information about stormwater service or other public works services, please contact one of the following agencies:

Water Service
  • One surface water treatment facility, the Hanahan Water Treatment Plant
  • Permitted capacity: 118 million gallons per day (mgd)
  • Daily flow
    • Average: 58 mgd
    • Max: 78 mgd
  • Serves approximately 400,000 people
  • Retail accounts: 113,000
  • Retail service area includes:
    • Charleston
    • North Charleston
    • Hanahan
    • Ladson
    • James Island
    • Daniel Island
    • Cainhoy
    • Thomas Island
    • West Ashley
    • Hollywood
    • Ravenel
    • Meggett
    • See map >>
  • Wholesale service area includes:
    • St. Johns Water Company (serves Kiawah and Seabrook Islands)
    • Mt. Pleasant Waterworks
    • Dorchester County Public Works
    • Town of Folly Beach
    • Town of Sullivan's Island
    • Isle of Palms Water and Sewer Commission
    • Joint Base Charleston
    • See map >> 
  • 1,800 miles of water mains
  • 9,300 fire hydrants

Sewer Service
  • Two treatment facilities:
    • Plum Island Wastewater Treatment Plant (main facility)
    • Daniel Island Plant (pre-treatment only)
  • Plum Island Plant Stats:
    • Permitted capacity: 36 mgd
    • Average daily flow: 19 mgd
  • Approximately 180,000 people served
  • Retail and wholesale services provided
  • Retail accounts: 52,000
  • View map of our retail service area
  • Wholesale service area includes:
    • Folly Beach
    • Hollywood
    • Meggett
    • Ravenel
    • James Island Public Service District
    • See map
  • Miles of sewer mains
    • 540 miles of gravity sewer
    • 115 miles of force main
    • 138 miles of service laterals
    • 12 miles of deep sewer tunnels
  • 187 wastewater pump stations