Clarks Hill Lake
Clarks Hill Lake in McCormick County, South Carolina has a water quality grade of C (Fair). Water clarity: 9.2 ft visibility. Chlorophyll-a (algae): 6.4 µg/L.
- Clarity
- 9.2 ft
- Type
- Mesotrophic
- Trend
- ↓ Declining
Clarks Hill Lake is a mesotrophic lake in McCormick County, South Carolina. Water quality is graded C based on 1 sampling years through 2025. Overall water quality is declining over recent sampling years. Compared to the 3 other monitored lakes in McCormick County, Clarks Hill Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, SCDES, last sampled 2025-10-01. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyModerate
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.
Generally safe for swimming, moderate water quality
Water Quality Grade: C (Fair)
Moderate clarity, visible to about 9.2 ft. Chlorophyll-a: 6.4 µg/L. Trophic State Index: 47.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 9.2 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | 6.4 µg/L | Fair |
| Trophic State Index (TSI) | 47 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Clarks Hill Lake
Compare lakeside cabins, hotels, and vacation rentals near Clarks Hill Lake in McCormick 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 Clarks Hill Lake
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Fishing Clarks Hill Lake
Water Quality Trend: ↓ Declining
Based on 14 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | -0.034 m/yr | 14 |
| Phosphorus | ↓ Declining | +4.89 µg/L/yr | 4 |
| Chlorophyll-a | ↓ Declining | +0.26 µg/L/yr | 14 |
County Ranking
Ranked #3 of 4 lakes in McCormick County
Nearby Lakes in McCormick County
Frequently asked questions about Clarks Hill Lake
What is the water quality grade for Clarks Hill Lake?
- Clarks Hill Lake in McCormick County, South Carolina has a water quality grade of C (Fair). Water clarity: 9.2 ft visibility. Chlorophyll-a (algae): 6.4 µg/L.
Is Clarks Hill Lake safe to swim in?
- Generally safe for swimming, moderate water quality. Clarks Hill Lake has a water quality grade of C (Fair). Algae concentration (chlorophyll-a) is 6.4 µg/L. Always check local health department advisories before swimming.
Explore Clarks Hill Lake 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 C Lakes in South Carolina
Mesotrophic Lakes in South Carolina
Where this data comes from
152 measurements from 1 monitoring station, 2013–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Georgia DNR Environmental Protection Division
21GAEPD_WQX152 samples · 2013–2025
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: 2025-10-01
Monitoring stations: 1