Lake Marion
Seminole County, FloridaEutrophic
Lake Marion is a productive, nutrient-rich eutrophic lake in Seminole County, Florida. Water quality is graded D based on 2 sampling years through 2025. Compared to the 167 other monitored lakes in Seminole County, Lake Marion ranks #132 for water quality.
Source: EPA Water Quality Portal sampling records, Florida DNR, last sampled 2025-07-01. Grade methodology: LakeGrade methodology.
Watch Lake Marion water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Swimming Safety
Swimming not recommended, poor water quality with high algae risk
Water Quality Grade: D, Poor
Very murky, less than 2 ft of visibility. Phosphorus level: 38 µg/L. Trophic State Index: 62.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2 ft | F |
| Phosphorus | 38 µg/L | C |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 62 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Location
County Ranking
Ranked #132 of 168 lakes in Seminole County
Cleaner Lakes Within 30 Miles
Lake Marion holds Grade D. 5 nearby lakes hold higher grades.
- BTrout LakeSeminole County · 1.3 mi · Two grade letters higher (D → B)
- BLake LotusSeminole County · 1.4 mi · Two grade letters higher (D → B)
- CLake MobileSeminole County · 1 mi · Higher grade (D → C)
- CSeminole-Orienta North LakeSeminole County · 1.3 mi · Higher grade (D → C)
- CLkflorida LakeSeminole County · 0.5 mi · Higher grade (D → C)
Nearby Lakes in Seminole County
More Florida Lake Rankings
Other Grade D Lakes in Florida
Eutrophic Lakes in Florida
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Most recent sample: 2025-07-01
Monitoring stations: 1
Where to stay near Lake Marion
Compare lakeside cabins, hotels, and vacation rentals near Lake Marion in Seminole County, Florida — live availability and prices for your trip.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.