Lake Thonotosassa
Hillsborough County, FloridaView mapDirections
Florida DEP publishes the water-quality measurements for Lake Thonotosassa. Here is what has been measured.
- Hypereutrophic
- Impaired · Algal growth
- Public access
- Limited data
Lake Thonotosassa in Hillsborough County, Florida has water-quality measurements published by Florida DEP, shown here as reported. Water clarity: 1.3 ft visibility. Phosphorus: 380 µg/L.
Lake Thonotosassa is a highly nutrient-loaded hypereutrophic lake in Hillsborough County, Florida. Water clarity is improving over recent sampling years. Limited fish-species data available. Public access is available. Compared to the 123 other monitored lakes in Hillsborough County, Lake Thonotosassa ranks #104 for water quality.
Source: EPA Water Quality Portal sampling records, FDEP, last sampled 2025-07-14. Methodology: how these readings are compared.
Vrbo is where to look for cabins and lake homes around Lake Thonotosassa, and Booking.com and Expedia search hotels near the lake for your dates.
Swimming conditions
Readings onlyRecreation use not supported
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Lake Thonotosassa is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, impaired biota (cause unknown), nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Lake Thonotosassa is safe to swim in today is a call for the Florida Department of Environmental Protection and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Lake Thonotosassa
These are the measurements Florida DEP publishes for Lake Thonotosassa, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 1.3 ft of visibility. Phosphorus 380 µg/L. TSI 82.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 1.3ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 380µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 82 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Lake Thonotosassa
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Lake Thonotosassa typically sits around 81°F at the surface in October. Summer average is about 86°F. Usually warmest in Jul (about 87°F) and coldest in Dec (about 64°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (64°F) to its warmest (87°F).
Typical surface water temperature by month, from 43 field readings (2017–2025) via the EPA Water Quality Portal. See the full Lake Thonotosassa water temperature breakdown →
Stays via Stay22
Stays near Lake Thonotosassa
Compare lakeside cabins, hotels, and vacation rentals near Lake Thonotosassa 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. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around Lake Thonotosassa are listed below.
Top-rated places to stay near Lake Thonotosassa
Prices for Oct 16–18, 4 adults. Change dates on the map below.
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Fishing Lake Thonotosassa
Water Quality Trend: Stable
Based on 6 years of monitoring (2020–2025).
Water clarity
Improving6 years
Phosphorus
Worsening+8.56 µg/L/yr6 years
EPA Impairment Status
Lake Thonotosassa is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Aquatic life, Recreation.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit FL1522B · Official waterbody report
Nearby Lakes in Hillsborough County
Frequently asked questions about Lake Thonotosassa
Where is Lake Thonotosassa?
- Lake Thonotosassa is a lake in Hillsborough County, Florida. Its water-quality measurements are published by Florida DEP and shown on this page as reported.
What is the water quality of Lake Thonotosassa?
- Lake Thonotosassa in Hillsborough County, Florida has water-quality measurements published by Florida DEP, shown here as reported. Water clarity: 1.3 ft visibility. Phosphorus: 380 µg/L.
Is Lake Thonotosassa safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Lake Thonotosassa is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, impaired biota (cause unknown), nutrients (phosphorus, nitrogen). Check local advisories before you swim.
What is the water temperature of Lake Thonotosassa?
- Lake Thonotosassa typically sits around 81°F at the surface in October, from 43 EPA Water Quality Portal field readings (2017–2025). That is a typical value for the month, not a live reading.
Can I fish at Lake Thonotosassa?
- Public access to Lake Thonotosassa is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by Florida's fish and wildlife agency, so check its current regulations before you go.
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Where this data comes from
30 measurements from 1 monitoring station, 2022–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Submitting organization not recorded for these samples30 samples · 2022–2025
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database