Hillsborough-Grady Lake
Hillsborough County, Florida120 acresView mapDirections
Florida DEP publishes the water-quality measurements for Hillsborough-Grady Lake. Here is what has been measured.
- Hypereutrophic
- Limited data
Hillsborough-Grady Lake in Hillsborough County, Florida has water-quality measurements published by Florida DEP, shown here as reported. Water clarity: 1.8 ft visibility. Phosphorus: 107 µg/L. Surface area: 120 acres.
Hillsborough-Grady Lake is a 120-acre highly nutrient-loaded hypereutrophic lake in Hillsborough County, Florida. Overall water quality is declining over recent sampling years. Compared to the 123 other monitored lakes in Hillsborough County, Hillsborough-Grady Lake ranks #106 for water quality.
Source: EPA Water Quality Portal sampling records, FDEP, last sampled 2024-03-07. Methodology: how these readings are compared.
Swimming conditions
Readings onlyLimited data
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. Check local advisories before you swim.
Whether Hillsborough-Grady Lake 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 Hillsborough-Grady Lake
These are the measurements Florida DEP publishes for Hillsborough-Grady Lake, 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 1.8 ft of visibility. Phosphorus 107 µg/L. TSI 70.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 1.8ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 107µg/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. | 70 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Hillsborough-Grady Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
120 acres
No bathymetric survey has been published for Hillsborough-Grady Lake, so its depth is not documented here.
Stays via Stay22
Stays near Hillsborough-Grady Lake
Compare lakeside cabins, hotels, and vacation rentals near Hillsborough-Grady 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. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around Hillsborough-Grady Lake are listed below.
Top-rated places to stay near Hillsborough-Grady Lake
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Fishing Hillsborough-Grady Lake
Water quality readings over time
3 seasons of samples on record (2022–2025). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Worsening3 years
Phosphorus
Worsening+27.93 µg/L/yr3 years
Reservoir Info (USACE NID)
Hillsborough-Grady Lake is a man-made reservoir impounded by the Shadow Run Dam (completed 1969), built primarily for recreation on the Bell Creek; earth-type dam, 30 ft tall and 1,015 ft long.
- Surface area
- 120 ac
- Normal storage
- 750 ac-ft
- Max storage
- 3,119 ac-ft
- Drainage area
- 17.43 sq mi
- Hazard class
- High
- Owner
- SHADOW RUN DAM CORP
All listed purposes: Recreation;Fish and Wildlife Pond.
Source: USACE National Inventory of Dams, NID ID FL00176 · Operator website · Matched by proximity (0.34 km)
Nearby Lakes in Hillsborough County
Frequently asked questions about Hillsborough-Grady Lake
Where is Hillsborough-Grady Lake?
- Hillsborough-Grady Lake 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 Hillsborough-Grady Lake?
- Hillsborough-Grady Lake in Hillsborough County, Florida has water-quality measurements published by Florida DEP, shown here as reported. Water clarity: 1.8 ft visibility. Phosphorus: 107 µg/L. Surface area: 120 acres.
Is Hillsborough-Grady Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Explore Hillsborough-Grady Lake across LakeQuality
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Where this data comes from
88 measurements from 3 monitoring stations, 2023–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- FLORIDA LAKEWATCH
21FLKWAT_WQX88 samples · 2023–2024
Monitoring station identifiers (3)
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.