Pinellas-Harbor-Isle Lake
Pinellas County, FloridaEutrophic
Pinellas-Harbor-Isle Lake is a productive, nutrient-rich eutrophic lake in Pinellas County, Florida. Water quality is graded D based on 2 sampling years through 2021. Compared to the 54 other monitored lakes in Pinellas County, Pinellas-Harbor-Isle Lake ranks #32 for water quality.
Source: EPA Water Quality Portal sampling records, Florida DNR, last sampled 2021-07-30. Grade methodology: LakeGrade methodology.
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Swimming Safety
Swimming not recommended, poor water quality with high algae risk
Water Quality Grade: D, Poor
Murky, only visible to about 3.5 ft. Phosphorus level: 115.5 µg/L. Trophic State Index: 66.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.5 ft | D |
| Phosphorus | 115.5 µg/L | F |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 66 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Location
County Ranking
Ranked #32 of 55 lakes in Pinellas County
Cleaner Lakes Within 30 Miles
Pinellas-Harbor-Isle Lake holds Grade D. 2 nearby lakes hold higher grades.
- BPinellas-Hewitt LakePinellas County · 6 mi · Two grade letters higher (D → B)
- DPinellas-Crescent LakePinellas County · 3.9 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 Pinellas-Harbor-Isle Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 1 facility has a reported Clean Water Act violation in the past three years.
- Duke Energy Florida - Bartow PlantSt Petersburg · 1.7 mi away · NPDES FL0000132MajorRecent violation
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: 2021-07-30
Monitoring stations: 3
Where to stay near Pinellas-Harbor-Isle Lake
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