Drinking Water Quality
The Safe Drinking Water Act (SWA) is the federal law that ensures the quality of public drinking water. The Environmental Protection Agency (EPA) has established national health-based standards to protect against natural and man-made contaminants that may be found in drinking water. SCDHEC regulates public water systems to make sure that these standards are met. Public water systems are required to test their water frequently, treat the water if any standards are not met, and notify their customers of the water quality. Public drinking water systems provide drinking water to 78% of South Carolina residents, the majority of which meet all health-based water quality standards.
It is important to note that drinking water comes from one of two sources in South Carolina - either treated surface water or groundwater. Public water systems are required to provide their customers with a water quality report, known as the Consumer Confidence Report (CCR). If your drinking water provider is not listed you can get a copy of the report by contacting them directly.
Private Wells are considered private property and are not regulated by federal standards. In most cases, if the well is properly drilled and developed, private wells have few water quality issues. People with private wells are responsible for testing and treating their own drinking water, and it is recommended that the well water be tested annually to see if it meets federal and state standards.
The federal Centers for Disease Control and Prevention (CDC) tracks information about the environment and human health, and the Bureau of Water at SC DHEC is tracking arsenic, nitrate, and disinfection byproducts in public drinking water as part of the CDC’s National Environmental Public Health Tracking Program.
What is arsenic?
Arsenic is an odorless and tasteless element that may enter drinking water supplies from natural deposits in the earth or from agricultural and industrial practices.
Where does arsenic come from?
Arsenic enters drinking water supplies from natural deposits in the earth or from agricultural and industrial practices. It is also a byproduct of copper smelting, mining, and coal burning. It can enter your drinking water through the ground or as runoff into surface water sources.
How can arsenic affect me?
The EPA has set a maximum contaminant level (MCL) for arsenic at 10 micrograms per liter.
Exposure to arsenic can cause nausea and vomiting, decreased production of red and white blood cells, abnormal heart rhythm, damage to blood vessels, and a sensation of “pins and needles” in hands and feet. Long-term exposure to arsenic in children may result in lower IQ scores. Some people who drink water that contains arsenic in excess of the MCL over many years could experience skin damage or problems with their circulatory system, and may have an increased risk of getting certain cancers. Ingesting very high levels of arsenic can result in death.
What is nitrate?
Nitrates are a chemical unit of nitrogen and oxygen. Nitrates are converted to nitrites once taken into the body.
Where does nitrate come from?
Nitrates are mostly used as fertilizer. They may enter drinking water from runoff, septic tanks, sewage, and erosion of natural deposits.
How can nitrate affect me?
EPA has set a maximum contaminant level (MCL) for nitrate at 10 mg/L. Drinking water with levels of nitrate higher than 10 mg/L is especially dangerous for infants under six months. Nitrates reduce the ability of the blood to carry oxygen. In severe cases this can cause babies to turn blue and is sometimes called “Blue Baby Syndrome”. Immediate medical attention is necessary as this condition can become fatal. A lifetime of exposure to nitrates above the MCL can cause an increased discharge of urine, increased starchy deposits, and hemorrhaging of the spleen.
What are disinfection byproducts?
Disinfection byproducts are compounds that are produced when the disinfectant (usually chlorine) breaks down, or reacts with naturally-occurring organic and inorganic materials in the water.
Where do disinfection byproducts come from?
Disinfectants, such as chlorine or chloramines, are added to water to rid it of bacteria and disease causing microorganisms. Disinfection byproducts include several chemicals: trihalomethanes, haloacetic acids, and bromate. Trihalomethanes occur when organic and inorganic materials react with chlorine and chloramine. Haloacetic acids occur when organic and inorganic materials react with chlorine and chloramine. Bromate occurs when bromide reacts with ozone. Chlorite occurs when chlorine dioxide breaks down.
How can disinfection byproducts affect me?
The EPA has set a maximum contaminant level (MCL) of 80 micrograms per liter for THM’s and 60 micrograms per liter for HAA’s. Some people, such as pregnant women, young children, or immunocompromised persons are more at risk. These people could experience liver, kidney, or nervous system problems. Drinking water containing disinfection byproducts in excess of the MCL for many years increases the risk of certain cancers.
Drinking Water Quality Resouces and Materials
How can I protect myself from possible drinking water issues?
South Carolina regulates public drinking water systems. The water is tested, treated if necessary, and the customers are notified. The contaminants that the SC EPHT is tracking are arsenic, nitrates, and disinfection byproducts.
South Carolina does not regulate private drinking water such as wells on private property. If you do have concerns about your drinking water, contact your SC DHEC Regional Office and discuss your concern and you will be advised for the next step to take to get the concern resolved.
Other contaminants that could get into your drinking water include uranium, radium, polychloroethene (PCE), gasoline, and other chemicals from man-made sources. Drinking Water Compliance Monitoring describes how public drinking water systems are monitored for potential contaminants.
Unused and expired medicine (pharmaceuticals) is another contaminant that could get into your drinking water if it is not disposed of properly. Unused medication that is flushed down the toilet or poured down the drain could potentially make its way into our drinking water sources. Wastewater treatment plants do not currently treat for pharmaceuticals. SC DHEC does not currently monitor public drinking water systems for pharmaceuticals.
How can I protect myself from contaminants in my drinking water?
If your drinking water is contaminated, there are several methods such as reverse osmosis, ultra-filtration, distillation, or ion exchange to help treat your water. To learn more about treatment options, you may want to visit the National Sanitation Foundation (NSF) International’s web site. NSF International focuses on public health and safety through standards development, product certification, education, and risk management.
Remember to have your well water tested regularly, at least once a year, to make sure your water is safe.
How can I reduce contaminants from getting into the drinking water?
Reduce the pollutants you are putting into the environment such as washing your car near a storm drain or using harsh weed killers on the grass. These and other man-made pollutants are picked up by rainfall or snowmelts and carried into lakes, rivers, wetlands, and ground waters. You may hear this referred to as nonpoint source pollution runoff . Unlike pollution from industrial and sewage treatment plants, nonpoint source (NPS) pollution comes from many different sources instead of one source or location.
Lawn & Garden
- Use native plants; they often require less water and fertilizer.
- Landscape with plants that filter pollutants and reduce runoff.
- Test soil to determine fertilization needs.
- Use environmentally safe fertilizers and pesticides when possible.
- Compost leaves, grass and yard waste.
- NEVER drain any automotive fluids into storm drains.
- Service your car regularly.
- Wash your car on the grass or at a car wash to reduce runoff into storm drains.
- Clean up leaks.
- Drive less.
WaterSense is a partnership program sponsored by EPA. The program’s mission is to protect our future water supply through water efficient products and services. It’s a lot like Energy Star.
This toolbox is designed for stormwater professionals, stormwater stakeholder groups and anyone else interested in developing outreach programs to encourage the public to reduce their contribution to polluted runoff.
Champions of the Environment rewards K-12th grade students and teachers for environmental projects.
The All-Health Team rewards youths and their leaders for promoting healthy eating and being active.
Drinking Water Quality Maps
See our new Dynamic Portal to view Drinking Water Quality Maps
Drinking Water Quality Data
Directions: In order to view data tables, you must click on the year of interest. Once the table is open for viewing, you can close the table by clicking on the year again.
Number of Community Water Systems and Total Population Served (1999-2010)
Number of CWS1
Total Population Served
1 Community Water System (CWS) A Community Water System or CWS is defined by the EPA as a public water system that supplies water to the same population year-round. A public water system is defined as one that provides water for human consumption through a pipe or other constructed conduit to at least fifteen (15) service connectors or serves an average of at least twenty-five (25) people for at least sixty (60) days a year.
Number of Community Water Systems (CWS) and Population Served by Mean Arsenic Concentrations (micrograms per liter), by Quarter (1999) (2000) (2001) (2002) (2003) (2004) (2005) (2006) (2007) (2008) (2009) (2010)
Disinfection Byproduct (DBP) Data
Number of Community Water Systems (CWS) and Population Served by Mean THM Concentrations (micrograms per liter), by Quarter (1999) (2000) (2001) (2002) (2003) (2004) (2005) (2006) (2007) (2008) (2009) (2010)
Number of Community Water Systems (CWS) and Population Served by Mean HAA5 Concentrations (micrograms per liter), by Quarter (1999) (2000) (2001) (2002) (2003) (2004) (2005) (2006) (2007) (2008) (2009) (2010)
Number of Community Water Systems (CWS) and Population Served by Mean Nitrate Concentrations (milligrams per liter), by Quarter (1999) (2000) (2001) (2002) (2003) (2004) (2005) (2006) (2007) (2008) (2009) (2010)
|Explore the SC EPHT dynamic portal to view drinking water data by specific community water system.|
- Arsenic - An odorless and tasteless element that may enter drinking water supplies from natural deposits in the earth or from agricultural and industrial practices. Arsenic enters drinking water supplies from natural deposits in the earth or from agricultural and industrial practices and through the ground or as runoff into surface water sources.
- Nitrates- A chemical unit of nitrogen and oxygen. Nitrates are converted to nitrites once taken into the body. Nitrates are mostly used as fertilizer. They may enter drinking water from runoff, septic tanks, sewage, and erosion of natural deposits.
- Disinfection byproducts- Compounds that are produced when the disinfectant (usually chlorine) breaks down, or reacts with naturally-occurring organic and inorganic materials in the water. Disinfectants are added to water to rid it of bacteria and disease causing microorganisms.
- Safe Drinking Water Act (SWA) – Originally passed by Congress in 1974 to protect public health drinking water. It was amended in 1986 and 1996 to protect drinking water and its sources.
- Nonpoint Source Runoff Pollution (or stormwater runoff) – Occurs when rainfall or melting snow moves over and through the ground and it picks up and carries natural and human-made pollutants into lakes, rivers, wetlands, coastal waters and ground waters.
- Bureau of Water
- Understanding Your Drinking Water
- Drinking Water Compliance Report 2008
- Radium brochure
- Residential Well Program
- CDC Drinking Water –Drinking water topics and fast facts
- EPA Drinking Water –Drinking water topics and fast facts
- National Library of Medicine Drinking Water - The National Library of Medicine page containing additional information about Drinking Water.
- Pesticides in Drinking Water -The National Pesticide Telecommunications Network (regulated by the EPA) most commonly asked questions about pesticides and drinking water.
- Tox Town Drinking Water- An interactive web site that contains information on sources of Drinking Water and runoff pollution.