Lake Seminole
Pinellas County, FloridaEutrophic
Lake Seminole is a productive, nutrient-rich eutrophic lake in Pinellas County, Florida. Water quality is graded D based on 2 sampling years through 2025. Compared to the 54 other monitored lakes in Pinellas County, Lake Seminole ranks #29 for water quality.
Source: EPA Water Quality Portal sampling records, Florida DNR, last sampled 2025-03-04. Grade methodology: LakeGrade methodology.
Watch Lake Seminole water quality
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Swimming Safety
Swimming not recommended, poor water quality with high algae risk
Water Quality Grade: D, Poor
Very murky, less than 1.6 ft of visibility. Phosphorus level: 60 µg/L. Trophic State Index: 67.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.6 ft | F |
| Phosphorus | 60 µg/L | D |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 67 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Location
County Ranking
Ranked #29 of 55 lakes in Pinellas County
Cleaner Lakes Within 30 Miles
Lake Seminole holds Grade D. 2 nearby lakes hold higher grades.
- CPinellas-Bellevue LakePinellas County · 4.9 mi · Higher grade (D → C)
- DEagle LakePinellas County · 4 mi · Higher overall water quality score
Nearby Lakes in Pinellas County
More Florida Lake Rankings
Other Grade D Lakes in Florida
Eutrophic Lakes in Florida
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Lake Seminole under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger.
- Fdot District 7Tampa · 3 mi away · NPDES FLS648434Major
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Data Sources
Water quality data from the EPA Water Quality Portal
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grading methodology based on Metropolitan Council standards
Most recent sample: 2025-03-04
Monitoring stations: 77
Where to stay near Lake Seminole
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