St. Johns County Lake Quality
Florida, 4 lakes, average grade D (Nutrient-rich)
Only 4 lakes in St. Johns County carry an active grade. The county-level summary is therefore representative of those specific lakes, not necessarily of every water body in the county. The county-wide average grade is D — water quality issues are persistent across most of the monitored basins. 0 lakes fall into the F bracket outright.
Most of the county's monitored lakes are shallow — under 50 feet — which means wind keeps the water column mixed all summer and sediment-bound phosphorus releases back into the surface layer whenever the bottom is disturbed. Lake South (D) is the cleanest in the county.
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Quick Answers for St. Johns County
Planning a trip? Check special fishing regulations for Lake South — or check the official Florida fishing regulations.
All Lakes in St. Johns County
4 lakes4 graded lakes
| # | Lake | Grade | Clarity | Phosphorus | Algae | Trophic | Access |
|---|---|---|---|---|---|---|---|
| 1 | DLake SouthSt. Johns | D | 1.6 ft | 78 µg/L | No recent samples | No recent samples | ✓ Public |
| 2 | DLake MidSt. Johns | D | 2.1 ft | 103.5 µg/L | No recent samples | No recent samples | Not recorded |
| 3 | DLake VedraSt. Johns | D | 2.3 ft | 360 µg/L | No recent samples | No recent samples | Not recorded |
| 4 | DMicklers LakeSt. Johns | D | 1.7 ft | 149 µg/L | No recent samples | No recent samples | Not recorded |
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Other Counties in Florida
See how St. Johns County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 49 states and 2 Canadian provinces.
Source: EPA National Aquatic Resource Surveys, 2026.