SCDES, Charleston Waterkeepers begin monitoring swim water quality

Summer is near, and soon residents and tourists alike will be getting their swim on along South Carolina’s coastlines.

To help keep South Carolina beaches a favorite destination, the South Carolina Department of Environmental Services monitors water quality along the coast. Every state with ocean-facing beaches performs beach water monitoring to help detect instances of elevated bacteria levels that have the potential to impact people’s health.

From May 1 to October 30, SCDES collects either weekly or biweekly water samples at 122 locations along South Carolina's beaches, from Cherry Grove Beach near the South Carolina-North Carolina border to the southern end of Hilton Head Island. SCDES staff test these water samples for Enterococci bacteria. If elevated levels of the bacteria are detected, the agency issues public notices at that beach location and on SCDES’s Beach Monitoring webpage and the South Carolina Beach Access Guide web app because high levels of Enterococci bacteria could negatively impact some people’s health.

“If levels of Enterococci bacteria exceed the standard limit, we quickly issue a short-term swimming advisory for that portion of the beach to help alert beachgoers,” said Courtney Kemmer, manager of SCDES’s Aquatic Resource Monitoring, in a statement. “A swimming advisory doesn’t mean a beach is closed, it just means that a particular area of ocean water should be avoided until the bacteria levels return to normal. Most short-term swimming advisories last just a single day.” 

SCDES tests ocean water for Enterococci bacteria, which are naturally found in warm-blooded animals, including humans. However, high levels of Enterococci in water indicate the potential risk for other organisms that may cause disease in humans, such as gastrointestinal illness or skin infections.

The current advisory status for all 122 sampling sites is available on the online S.C. Beach Access Guide.

SCDES issues two types of swimming advisories, short-term, or temporary, and long-term: 

• Short-term swimming advisories typically last one to two days and are issued when two consecutive water samples exceed the state water quality standard of 104 colony-forming units per 100 milliliters (104 CFU/100mL). Often, short-term swim advisories due to elevated bacteria levels are issued after heavy rains, when rainwater washes pollutants into the ocean.

• Long-term swimming advisories are issued year-round for areas that have an increased possibility of high bacteria levels, typically where stormwater from pipes or small creeks flows across the beach and into the ocean. Signs posted at these locations provide information about the potential of high bacteria levels. Locations with long-term advisories are reevaluated at the beginning of each year.

“We don’t always know the cause of the increase in bacteria in a certain area because there could be various contributing factors, however, it’s our job as South Carolina’s environmental agency to keep the public informed of current bacterial counts within ocean water,” Kemmer said. “It’s important to remember that ocean water isn’t chemically controlled like swimming pool water, and swimming in any natural water body presents the risk of coming into contact with potentially harmful bacteria and viruses.” 

Visit des.sc.gov/beachmonitoring to learn more.

In Charleston, water quality is also monitored by Charleston Waterkeepers with its Swim Alert project.

The Swim Alert project tests bacteria levels at 20 popular sites around the Charleston area so you know when and where it’s safe to swim. Samples are collected and analyzed every Wednesday, May through the end of October, to determine the amount of Enterococcus bacteria present. Testing results are published as soon as they are available so you can make informed choices about how to keep yourself and your family safe on the water.

All data is collected and generated under a DHEC-approved Quality Assurance Project Plan. Samples are analyzed by Charleston Waterkeeper staff at the College of Charleston’s Department of Geology and Environmental Geosciences’s Hydro Chemistry Research Laboratory. Results that exceed South Carolina’s water quality standard of 104 CFU/100 mL are noted in red and indicate swimming may expose you to pathogens. 

Charleston Waterkeeper uses the Swim Alert data to identify polluted waterways and advocate for clean-up projects and funding. Since 2013, Swim Alert has helped secure more than $1 million in state and local funding for clean-up work in local creeks and rivers like James Island and Ellis Creeks.

Swim Alert Data from past seasons is available online.