Lake Marion
Lake Marion in Clarendon County, South Carolina has a water quality grade of B (Good). Water clarity: 4.3 ft visibility. Phosphorus: 22 µg/L. Chlorophyll-a (algae): 9.8 µg/L.
- Clarity
- 4.3 ft
- Type
- Eutrophic
Lake Marion is a productive, nutrient-rich eutrophic lake in Clarendon County, South Carolina. Water quality is graded B based on 1 sampling years through 2019. 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. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLimited data
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Good for swimming, clear water with low algae levels
Water Quality Grade: B (Good)
Murky, only visible to about 4.3 ft. Phosphorus level: 22 µg/L. Chlorophyll-a: 9.8 µg/L. Trophic State Index: 53.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.3 ft | Not graded |
| Phosphorus | 22 µg/L | Not graded |
| Chlorophyll-a (Algae) | 9.8 µg/L | Good |
| Trophic State Index (TSI) | 53 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Lake Marion
Compare lakeside cabins, hotels, and vacation rentals near Lake Marion in Clarendon County, South Carolina — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Lake Marion
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Fishing Lake Marion
County Ranking
Ranked #14 of 33 lakes in Clarendon County
Nearby Lakes in Clarendon County
Frequently asked questions about Lake Marion
What is the water quality grade for Lake Marion?
- Lake Marion in Clarendon County, South Carolina has a water quality grade of B (Good). Water clarity: 4.3 ft visibility. Phosphorus: 22 µg/L. Chlorophyll-a (algae): 9.8 µg/L.
Is Lake Marion safe to swim in?
- Good for swimming, clear water with low algae levels. Lake Marion has a water quality grade of B (Good). Algae concentration (chlorophyll-a) is 9.8 µg/L. Always check local health department advisories before swimming.
Explore Lake Marion across LakeGrade
More South Carolina Lake Rankings
Top 25 by overall water quality score
Top 25 by Secchi water clarity
Grade A/B + low algae filter
Panfish-rich, public access
Full state directory
Other Grade B Lakes in South Carolina
Eutrophic Lakes in South Carolina
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)
Grade thresholds come from the U.S. EPA National Lakes Assessment 2022 Technical Support Document (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Data Sources
Water quality data from the EPA Water Quality Portal
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion
Most recent sample: 2019-12-10
Monitoring stations: 1