Lake Marion
Clarendon County, South CarolinaView mapDirections
SCDHEC publishes the water-quality measurements for Lake Marion. Here is what has been measured.
- Eutrophic
- Limited data
Lake Marion in Clarendon County, South Carolina has water-quality measurements published by SCDHEC, shown here as reported. Water clarity: 4.3 ft visibility. Phosphorus: 22 µg/L. Chlorophyll-a (algae): 9.8 µg/L.
Lake Marion is a productive, nutrient-rich eutrophic lake in Clarendon County, South Carolina. Compared to the 32 other monitored lakes in Clarendon County, Lake Marion ranks #14 for water quality.
Source: EPA Water Quality Portal sampling records, SCDES, last sampled 2019-12-10. Methodology: how these readings are compared.
Swimming conditions
Readings onlyLimited data
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Lake Marion is safe to swim in today is a call for the South Carolina Department of Health and Environmental Control and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Lake Marion
These are the measurements SCDHEC publishes for Lake Marion, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 4.3 ft. Phosphorus 22 µg/L. Chlorophyll-a 9.8 µg/L. TSI 53.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 4.3ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 22µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | 9.8µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 53 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
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Nearby Lakes in Clarendon County
Frequently asked questions about Lake Marion
Where is Lake Marion?
- Lake Marion is a lake in Clarendon County, South Carolina. Its water-quality measurements are published by SCDHEC and shown on this page as reported.
What is the water quality of Lake Marion?
- Lake Marion in Clarendon County, South Carolina has water-quality measurements published by SCDHEC, shown here as reported. Water clarity: 4.3 ft visibility. Phosphorus: 22 µg/L. Chlorophyll-a (algae): 9.8 µg/L.
Is Lake Marion safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
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Where this data comes from
23 measurements from 1 monitoring station, 2019. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Submitting organization not recorded for these samples23 samples · 2019
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.