What We Do

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

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

Our Hanahan Water Treatment Plant produces high quality drinking water delivered to our customers through 1,800 miles of water mains. Our 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 800 miles of collection mains, 209+ pump stations, and 12 miles of deep tunnels that carry wastewater to our Plum Island Wastewater Treatment Plant. The plant treats an average of 25 million gallons a day and releases clean water into Charleston harbor.

We're committed to preventing pollution and improving the environment. We've implemented an environmental management system (EMS) and have been certified under ISO 14001:2015, the international standard for environmental management.

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

Water Service

  • One surface water treatment facility:
    Hanahan Water Treatment Plant
  • SCDHEC permitted capacity: 115.4 million gallons per day (mgd)
  • Daily flow
    • Average: 58 mgd
    • Winter Storm Grayson (1/2018) 96 mgd
    • Record Volume (12/1999) 105.5 mgd
  • Serves approximately 450,000 people
  • Retail accounts: 120,000
  • 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
    • Town of Lincolnville (8/2018)
    • See map >> 
  • 1,800 miles of water mains
  • 9,800 fire hydrants

Sewer Service
  • Two treatment facilities:
    • Plum Island Wastewater Treatment Plant (main facility)
    • Daniel Island Plant (pre-treatment only)
  • Plum Island stats:
    • Permitted capacity: 36 mgd
    • Average daily flow: 25 mgd
  • 180,000 people served
  • Retail and wholesale services
  • Retail accounts: 65,000
  • 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
  • 209 wastewater pump stations