Water Quality Reports
Understanding Water Quality Reports:
MRL -- Minimum Reporting Level
Smallest amount that can be measured by the test instrument. Any "Result" below the MRL is considered Non-Detect, or not present.
MCL -- Minimum Concentration Level
Regulatory limit defining the safe/acceptable amount of a substance.
Amounts shown as <X equal Non-Detect, or not present. Example: <2.0
Bold numbers illustrate a substance found in concentrations above the MRL (substances actually detected.)
mg/L milligrams per liter, which equals parts per million (ppm)
ng/L nanograms per liter, which equals parts per trillion (ppt)
umhos/cm micromhos per centimeter
This report provides monthly averages for water quality parameters.
Ad-Hoc Water Quality Reports
We tested our water in response to community concerns about these substances:
(8/02/17) - GenX & PFCs No GenX found. PFCs present far below EPA Health Advisory.
Annual Water Quality Report/ Consumer Confidence Report (CCR)
This report tells you where our water comes from and how it’s treated. It also provides a summary of our water quality test results and tells you whether we met all regulatory requirements. Water utilities are required to produce this report each year by July 1. Our report is typically available in May for the prior year's data.
2017 / most recent report (page view)
2017 / most recent report (poster view)Archived reports
Questions/Request hard copies
(843) 727-6800 or email
Drinking Water Fluoridation (
Adopted by the Board of Commissioners October 24, 2017
The Charleston Water System (CWS) supports the recommendations of the World Health Organization, American Medical Association, Canadian Medical Association, Centers for Disease Control and Prevention (CDC), American Dental Association, Canadian Dental Association, South Carolina Dental Association and other professional organizations in the medical community, for the proper fluoridation of public water supplies as a public health benefit. We also support regular scrutiny of the most current peer reviewed research on fluoride and the positions of the medical and dental community.
We adjust the naturally occurring level of fluoride in our drinking water in a responsible, effective, and reliable manner that includes monitoring and controlling fluoride levels as mandated by state and/or federal laws, regulations and recommendations. We carefully monitor and adjust potable water to achieve the scientifically recommended concentration of fluoride for protection against dental caries, which is 0.7 parts per million. Our annual cost for this program is about $110,000, which equates to $0.25 per person across the approximately 450,000 people in our water service area.
The CWS participates in the fluoridation of water under the guidance of the South Carolina Department of Health and Environmental Control (SCDHEC), Oral Health Division. SCDHEC coordinates their program in conjunction with the CDC and the U.S. Department of Health and Human Services.
If there are questions regarding these programs, please contact:
Division of Oral Health
2100 Bull Street, Columbia, S.C. 29201
P: (803) 898-9577
F: (803) 898-2065