Pinellas-Harbor-Isle Lake
Pinellas-Harbor-Isle Lake in Pinellas County, Florida has a water quality grade of D (Nutrient-rich). Water clarity: 3.5 ft visibility. Phosphorus: 115.5 µg/L.
- Clarity
- 3.5 ft
- Typical in August
- 88°F
- Type
- Eutrophic
- Trend
- ↑ Improving
- Public access
- Yes
Grade D measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Pinellas-Harbor-Isle Lake →
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Pinellas-Harbor-Isle Lake is a productive, nutrient-rich eutrophic lake in Pinellas County, Florida. Water quality is graded D based on 1 sampling years through 2021. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 33 other monitored lakes in Pinellas County, Pinellas-Harbor-Isle Lake ranks #22 for water quality.
Source: EPA Water Quality Portal sampling records, FDEP, last sampled 2021-07-30. Grade methodology: LakeQuality methodology.
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Swimming Safety
Grade onlyLimited data
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum
Water Quality Grade: D (Nutrient-rich)
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 | Not graded |
| Phosphorus | 115.5 µg/L | Poor |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 66 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Pinellas-Harbor-Isle Lake
Compare lakeside cabins, hotels, and vacation rentals near Pinellas-Harbor-Isle Lake in Pinellas County, Florida — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around Pinellas-Harbor-Isle Lake are listed below.
Top-rated places to stay near Pinellas-Harbor-Isle Lake
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Planning a whole trip? See where to stay at Florida’s top lakes →
Water Temperature
Pinellas-Harbor-Isle Lake typically sits around 88°F at the surface in August. Summer average is about 89°F. Usually warmest in Jul (about 90°F) and coldest in Feb (about 65°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 29 field readings (2020–2022) via the EPA Water Quality Portal. See the full Pinellas-Harbor-Isle Lake water temperature breakdown →
Recreation & Access
- Gandy Wayside ParkPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Pinellas-Harbor-Isle Lake
Water Quality Trend: ↑ Improving
Based on 3 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.15 m/yr | 3 |
| Phosphorus | ↑ Improving | -8.5 µg/L/yr | 3 |
EPA Impairment Status
Pinellas-Harbor-Isle Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit FL1661G · Official waterbody report · Matched by proximity (0.62 km)
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.
County Ranking
Ranked #22 of 34 lakes in Pinellas County
Nearby Lakes With Higher Grades
Pinellas-Harbor-Isle Lake holds Grade D. 2 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
Nearby Lakes in Pinellas County
Frequently asked questions about Pinellas-Harbor-Isle Lake
Where is Pinellas-Harbor-Isle Lake?
- Pinellas-Harbor-Isle Lake is a lake in Pinellas County, Florida. LakeQuality grades it D for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Pinellas-Harbor-Isle Lake?
- Pinellas-Harbor-Isle Lake in Pinellas County, Florida has a water quality grade of D (Nutrient-rich). Water clarity: 3.5 ft visibility. Phosphorus: 115.5 µg/L.
Is Pinellas-Harbor-Isle Lake safe to swim in?
- Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum. Pinellas-Harbor-Isle Lake has a water quality grade of D (Nutrient-rich). Always check local health department advisories before swimming.
What is the water temperature of Pinellas-Harbor-Isle Lake?
- Pinellas-Harbor-Isle Lake typically sits around 88°F at the surface in August, from 29 EPA Water Quality Portal field readings (2020–2022). That is a typical value for the month, not a live reading.
Are there boat ramps on Pinellas-Harbor-Isle Lake?
- Pinellas-Harbor-Isle Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Gandy Wayside Park. Public access is listed as yes.
Explore Pinellas-Harbor-Isle Lake across LakeQuality
More Florida Lake Rankings
Other Grade D Lakes in Florida
Hillsborough County · 2 ft
Hillsborough County · 3.3 ft
Hillsborough County · Nutrient-rich
Hillsborough County · Nutrient-rich
Hillsborough County · Nutrient-rich
Hillsborough County · Nutrient-rich
Eutrophic Lakes in Florida
Where this data comes from
42 measurements from 3 monitoring stations, 2020–2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- FLORIDA LAKEWATCH
21FLKWAT_WQX42 samples · 2020–2021
Monitoring station identifiers (3)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Named boat-access points from the USGS National Boat Ramps inventory