Frequently Asked Questions

No, we're fortunate to have an abundant water supply, even during drought conditions.

Yes, our source water includes naturally occurring fluoride (approximately 0.15 mg/L), and we adjust the level to approximately 0.7 mg/L during the treatment process. 

Drinking Water Fluoridation (Position Statement)
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:

SCDHEC
Division of Oral Health
2100 Bull Street, Columbia, S.C. 29201
P: (803) 898-9577
F: (803) 898-2065

We use chlorine dioxide and chloramines (a compound formed by combining ammonia and chlorine) to protect against harmful microorganisms.

Chloramines are more stable than chlorine in the water distribution system, and chloramine residuals help maintain consistent water quality. The amount of disinfectant is carefully measured to the lowest level needed to keep the water free of disease-causing organisms.

Charleston Water System prevents lead from corroding from lead pipes and plumbing into your drinking water water by adjusting the properties of our water. We add a food-grade corrosion inhibitor called orthophosphate during our water treatment process to form a barrier between the pipe and the water inside. As a direct result, our lead testing results have been far below the EPA’s limit of 10 parts per billion (ppb) since 1994.

Customers with lead pipes or plumbing can further minimize exposure by flushing out water that has been sitting in your plumbing for several hours or more. Just let your water run for up to two minutes before using it for cooking or drinking.

We offer free lead tests, which are available at our office locations:
- 103 St. Philip St., Downtown Charleston
- 6330 Murray Drive, Hanahan

Yes, Charleston Water System water is safe to drink, as it meets or exceeds all drinking water standards. Bottled or filtered water is also high quality, but it's much more expensive than tap water.

No. We use chloramines (a combination of chlorine and ammonia) to disinfect drinking water which are harmful to fish and other aquatic life. There are a number of products available at pet stores to remove chloramines from your fish tank.

Our tap water is safe for dog, cats, and other non-aquatic pets. And people too, of course...

Water spots on dishes are caused by minerals in the water left behind when water evaporates. To prevent this, use a rinsing agent in your dishwasher, which improves the sheeting action of water and helps to prevent spotting.

Also, be sure to use the proper amount of dish detergent. Too little may not get your dishes clean, and too much can cause etching, which is tiny scratches on the surface of the glass that cannot be removed. The optimal amount of detergent depends on the hardness of water (amount of minerals in the water). Our water's hardness level is about 58.4 ppm, or 3.4 gpg. Check your dishwasher's manual for the recommended amount of detergent to use.

There are a variety of factors that can impact the taste or smell of tap water but not change the quality or safety of the water. We're a surface water utility, so harmless algae in our water, when put through the treatment process, can give off harmless compounds that may cause the water to taste or smell “earthy” or “musty.” In most cases, taste and odor are purely aesthetic concerns, which are not reliable indicators of water safety.

No.

Our water has a very low sodium level (10mg/1 or less). This is substantially lower than most well water supplies and many bottled water brands.

This is caused by tiny air bubbles in the water.

Solution:  Let the water stand in a glass to allow air bubbles to rise to the top and disappear.

If there's a CHANCE that our water has become contaminated with bacteria, we will issue a precautionary Boil Water Advisory. The SC Department of Environmental Services (SCDES) requires a Boil Water Advisory under certain conditions, such as loss of system pressure following a water main break.

If an advisory is issued, we will notify customers in a variety of ways, depending on the area affected. During an advisory, customers should bring water to a vigorous boil for at least one minute and let it cool before using for cooking or drinking. This will kill any bacteria that may be in the water.

We treat water from the Bushy Park Reservoir and the Edisto River, both of which are surface water sources. We blend these sources and our water typically consists of 90% Bushy Park and 10% Edisto. All water is treated at our Hanahan Water Treatment Plant, which is permitted to treat up to 115.4 million gallons per day (mgd), making this plant the largest in South Carolina.

Discolored water can sometimes occur as a result of fire hydrant testing, valve testing, or work on a nearby water main. A change in the direction or velocity of water flow water can cause the iron compounds that accumulate in water mains to become suspended in the water, resulting in a discolored appearance.

Typically, our crews will open a nearby fire hydrant to flush out this discolored water before it reaches customer taps. If you experience discolored water, flush your plumbing by turning on a cold water faucet until the water runs clear. If it persists, call us at (843) 727-6800.