Flynn Lake
Flynn Lake in Hillsborough County, Florida is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 6 ft visibility.
- Clarity
- 6 ft
- Typical in August
- 86°F
- Trend
- ↓ Declining
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Why Flynn Lake has no grade
We grade a lake only when the monitoring record supports a letter: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Flynn Lake, the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity. Sampling here has recorded water clarity, but not phosphorus and algae (chlorophyll-a).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by FDEP and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Flynn Lake is a lake in Hillsborough County, Florida. Overall water quality is declining over recent sampling years.
Source: EPA Water Quality Portal sampling records, FDEP, last sampled 2024-07-30. Grade methodology: LakeQuality methodology.
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Flynn Lake
These readings exist but are not enough for an A–F grade — see why.
Murky, only visible to about 6 ft. Trophic State Index: 51.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 6 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 51 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Flynn Lake
Compare lakeside cabins, hotels, and vacation rentals near Flynn Lake in Hillsborough 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.
Top-rated places to stay near Flynn Lake
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Planning a whole trip? See where to stay at Florida’s top lakes →
Water Temperature
Flynn Lake typically sits around 86°F at the surface in August. Summer average is about 86°F. Usually warmest in Jun (about 87°F) and coldest in Jan (about 63°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 67 field readings (2017–2024) via the EPA Water Quality Portal. See the full Flynn Lake water temperature breakdown →
Fishing Flynn Lake
Water Quality Trend: ↓ Declining
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.53 m/yr | 5 |
| Phosphorus | ↓ Declining | +2.8 µg/L/yr | 5 |
EPA Impairment Status
Flynn 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 FL1402C · Official waterbody report · Matched by proximity (0.93 km)
Graded lakes near Flynn Lake
Flynn Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Hillsborough County
Frequently asked questions about Flynn Lake
Where is Flynn Lake?
- Flynn Lake is a lake in Hillsborough County, Florida. LakeQuality has not rated this lake (UNRATED) — the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity.
What is the water quality grade for Flynn Lake?
- Flynn Lake in Hillsborough County, Florida is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 6 ft visibility.
Is Flynn Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Flynn Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
What is the water temperature of Flynn Lake?
- Flynn Lake typically sits around 86°F at the surface in August, from 67 EPA Water Quality Portal field readings (2017–2024). That is a typical value for the month, not a live reading.
Explore Flynn Lake across LakeQuality
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Where this data comes from
45 measurements from 1 monitoring station, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- North American Lake Management Society
NALMS45 samples · 2020–2024
Monitoring station identifiers (1)
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