Lake Hancock
Polk County, Florida4,541 acresView mapDirections
Florida DEP publishes the water-quality measurements for Lake Hancock. Here is what has been measured.
- Hypereutrophic
- Impaired · Algal growth
Lake Hancock in Polk County, Florida has water-quality measurements published by Florida DEP, shown here as reported. Water clarity: 1 ft visibility. Phosphorus: 265 µg/L. Surface area: 4541 acres.
Lake Hancock is a 4,541-acre highly nutrient-loaded hypereutrophic lake in Polk County, Florida. Overall water quality is declining over recent sampling years. Compared to the 176 other monitored lakes in Polk County, Lake Hancock ranks #143 for water quality.
Source: EPA Water Quality Portal sampling records, FDEP, last sampled 2025-04-21. Methodology: how these readings are compared.
What Lake Hancock is good for
From access and monitoring records, not editorial picks.
- Big water4,541 acres
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 Hancock is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, impaired biota (cause unknown), nutrients (phosphorus, nitrogen), oxygen depletion (low DO). Check local advisories before you swim.
Whether Lake Hancock 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 Hancock
These are the measurements Florida DEP publishes for Lake Hancock, 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 ft of visibility. Phosphorus 265 µg/L. TSI 81.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 1ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 265µg/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. | 81 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Lake Hancock
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
4,541 acres
No bathymetric survey has been published for Lake Hancock, so its depth is not documented here.
Stays via Stay22
Stays near Lake Hancock
Compare lakeside cabins, hotels, and vacation rentals near Lake Hancock in Polk 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 Hancock are listed below.
Top-rated places to stay near Lake Hancock
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Fishing Lake Hancock
Water Quality Trend: Worsening
Based on 6 years of monitoring (2020–2025).
Water clarity
Worsening6 years
Phosphorus
Worsening+37.94 µg/L/yr6 years
Reservoir Info (USACE NID)
Lake Hancock is a man-made reservoir impounded by the P-11 (completed 1965), built primarily for flood risk reduction on the Saddle Creek; concrete-type dam, 10 ft tall and 110 ft long.
- Surface area
- 4,541 ac
- Normal storage
- 44,048 ac-ft
- Max storage
- 31,787 ac-ft
- Drainage area
- 131 sq mi
- Hazard class
- Significant
- Owner
- SWFWMD
Source: USACE National Inventory of Dams, NID ID FL13003 · Operator website
EPA Impairment Status
Lake Hancock 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 FL1623L · Official waterbody report
Nearby Lakes in Polk County
Frequently asked questions about Lake Hancock
Where is Lake Hancock?
- Lake Hancock is a lake in Polk 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 Hancock?
- Lake Hancock in Polk County, Florida has water-quality measurements published by Florida DEP, shown here as reported. Water clarity: 1 ft visibility. Phosphorus: 265 µg/L. Surface area: 4541 acres.
Is Lake Hancock safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Lake Hancock is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, impaired biota (cause unknown), nutrients (phosphorus, nitrogen), oxygen depletion (low DO). Check local advisories before you swim.
Explore Lake Hancock across LakeQuality
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Where this data comes from
55 measurements from 4 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Submitting organization not recorded for these samples55 samples · 2020–2025
Monitoring station identifiers (4)
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