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Evaluation of Freshwater Recreational Uses and Bacteria

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  • In 2010, DHEC conducted a study to determine which pathogen indicator will best protect public health during recreation in freshwater.
  • Weekly samples were taken and analyzed to compare freshwater recreational water quality indicators.
  • These web pages are designed to keep you informed as the study progresses.


The South Carolina Department of Health and Environmental Control (DHEC) has been evaluating our freshwater water quality standards for recreational uses. DHEC anticipates the evaluation will result in more meaningful and realistic protection for recreational uses of our State’s freshwaters. 

Recreational uses include activities with frequent full body immersion called primary contact (swimming, water skiing, other whole body water-contact sports) and those with a low chance of total body immersion called secondary contact (wading, boating, fishing).

Fishing Kayaking Beach
Secondary contact includes activities like fishing, where there is little chance of contact with the water above the waist. Kayaking or padding is generally secondary contact receation, unless the paddler enters or swallows the water. Swimming in a freshwater lake or river is considered primary contact recreation because of the likehood of being underwater.


Why Evaluate Freshwater Pathogen Indicators?

For more than twenty-five years DHEC has monitored the quality of our surface waters.  For freshwaters of the State, DHEC currently uses fecal coliform bacteria as the pathogen indicator of recreational water quality. Changes in science and technology now enable us to consider using other indicators to ensure that we are suitably protecting the citizens of South Carolina. 

In 1986, the U.S. Environmental Protection Agency (EPA) documented that other pathogen indicators (E. coli or Enterococcus) more closely predicted the occurrences of human gastroenteritis (upset stomach, nausea, diarrhea) based on data collected when swimmers were directly exposed in freshwater lakes with established public swimming areas. 

While it is true that neither of the indicator organisms may be directly responsible for causing the gastroenteritis, the EPA recommended that either E. coli or Enterococcus be used as the pathogen indicator for recreational use protection.  In almost all cases of water-borne illnesses, pathogens come from inadequately treated waste of humans or other warm-blooded animals.  Enterococcus and E. coli are more specific to sewage and fecal sources than the current fecal coliform bacteria methods. 

Data Collection

EPA is strongly encouraging states to replace fecal coliform bacteria in their standards with one of these alternatives.  DHEC collected weekly data for a comparison of all three indicators in freshwater locations across South Carolina.

The intent of this study was threefold:

  • To identify the most heavily used swimming areas in our state
  • To focus our limited resources on providing the greatest level of protection for these frequently used swimming areas and
  • To determine reasonable protection for areas infrequently used for swimming

Monitoring Information

DHEC State of South Carolina Monitoring Strategy
List of weekly sampling locations
General statewide map of weekly sampling locations
Pathogen Indicator Study Quality Assurance Project Plan
Addendum - Pathogen Indicator Study Quality Assurance Project Plan, June 4, 2009
Congaree National Park Research Permit
Raw Pathogen Indicator Study Data

Evaluation of Alternative Indicator Data

June 28, 2011 Updated Indicator Statistical Evaluation with Associated R Script

Indicator Changes

DHEC has amended R.61-68, Water Classifications and Standards, to change the bacterial indicator species for projection of recreational uses in freshwaters of the State. More information about this process can be found on our Water Quality Standards Page.

Additional Links

DHEC Regulation 61-68, Water Classifications and Standards
DHEC Regulation 61-69, Classified Waters
USEPA 1986 Bacteria Criteria document

USEPA Microbial (Pathogen) Web Page

Contact Us

Permitting Questions

Mike Montebello
(803) 898-4228

Monitoring Questions

David Chestnut
(803) 898-4066

Water Quality Standards

Jason Gillespie
(803) 898-4330