Gem Mary Lake
Orange County, FloridaOligotrophic
Gem Mary Lake is a cold, clear oligotrophic lake in Orange County, Florida. Water quality is graded A based on 2 sampling years through 2025. Compared to the 531 other monitored lakes in Orange County, Gem Mary Lake ranks #67 for water quality.
Source: EPA Water Quality Portal sampling records, Florida DNR, last sampled 2025-03-18. Grade methodology: LakeGrade methodology.
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Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
Good clarity, visible to about 10.3 ft. Phosphorus level: 7 µg/L. Trophic State Index: 38.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10.3 ft | B |
| Phosphorus | 7 µg/L | A |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 38 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Location
County Ranking
Ranked #67 of 532 lakes in Orange County
Nearby Lakes in Orange County
More Florida Lake Rankings
Other Grade A Lakes in Florida
Highlands County · Clarity: 16 ft
Walton County · Clarity: 9 ft
Highlands County · Clarity: 13.2 ft
Seminole County · Clarity: 11 ft
Seminole County · Clarity: 13 ft
Volusia County · Clarity: 14 ft
Oligotrophic Lakes in Florida
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Most recent sample: 2025-03-18
Monitoring stations: 1
Where to stay near Gem Mary Lake
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