Hillsborough-Charles Lake
Hillsborough-Charles Lake in Hillsborough County, Florida is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 4 ft visibility. Phosphorus: 18.5 µg/L.
- Clarity
- 4 ft
- Trend
- ↑ Improving
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Why Hillsborough-Charles 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 Hillsborough-Charles 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 and phosphorus, but not 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.
Hillsborough-Charles Lake is a lake in Hillsborough County, Florida. Overall water quality is improving over recent sampling years.
Source: EPA Water Quality Portal sampling records, FDEP, last sampled 2023-07-15. Grade methodology: LakeQuality methodology.
Watch Hillsborough-Charles Lake water quality
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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 Hillsborough-Charles Lake
These readings exist but are not enough for an A–F grade — see why.
Murky, only visible to about 4 ft. Phosphorus level: 18.5 µg/L. Trophic State Index: 52.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4 ft | Not graded |
| Phosphorus | 18.5 µg/L | Not graded |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 52 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Hillsborough-Charles Lake
Compare lakeside cabins, hotels, and vacation rentals near Hillsborough-Charles 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 Hillsborough-Charles Lake
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Fishing Hillsborough-Charles Lake
Water Quality Trend: ↑ Improving
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.07 m/yr | 5 |
| Phosphorus | ↑ Improving | -1.1 µg/L/yr | 5 |
EPA Impairment Status
Hillsborough-Charles Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit FL1502A · Official waterbody report · Matched by proximity (1.51 km)
Graded lakes near Hillsborough-Charles Lake
Hillsborough-Charles Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Hillsborough County
Frequently asked questions about Hillsborough-Charles Lake
Where is Hillsborough-Charles Lake?
- Hillsborough-Charles 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 Hillsborough-Charles Lake?
- Hillsborough-Charles Lake in Hillsborough County, Florida is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 4 ft visibility. Phosphorus: 18.5 µg/L.
Is Hillsborough-Charles Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Hillsborough-Charles Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
Explore Hillsborough-Charles Lake across LakeQuality
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Where this data comes from
20 measurements from 3 monitoring stations, 2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- FLORIDA LAKEWATCH
21FLKWAT_WQX20 samples · 2023
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