Hancock Outflow Lake
Polk County, Florida4,541 acresView mapDirections
Florida DEP publishes the water-quality measurements for Hancock Outflow Lake. Here is what has been measured.
- Hypereutrophic
- Limited data
Hancock Outflow Lake in Polk County, Florida has water-quality measurements published by Florida DEP, shown here as reported. Water clarity: 0.7 ft visibility. Phosphorus: 478 µg/L. Surface area: 4541 acres.
Hancock Outflow Lake 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, Hancock Outflow Lake ranks #171 for water quality.
Source: EPA Water Quality Portal sampling records, FDEP, last sampled 2025-09-15. Methodology: how these readings are compared.
What Hancock Outflow Lake is good for
From access and monitoring records, not editorial picks.
- Big water4,541 acres
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 Hancock Outflow 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 Hancock Outflow Lake
These are the measurements Florida DEP publishes for Hancock Outflow 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 0.7 ft of visibility. Phosphorus 478 µg/L. TSI 88.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 0.7ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 478µg/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. | 88 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Hancock Outflow Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Hancock Outflow Lake typically sits around 83°F at the surface in September. Summer average is about 84°F. Usually warmest in Jun (about 84°F) and coldest in Dec (about 67°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (67°F) to its warmest (84°F).
Typical surface water temperature by month, from 9 field readings (2023–2025) via the EPA Water Quality Portal. See the full Hancock Outflow Lake water temperature breakdown →
Lake Details
Surface area
4,541 acres
No bathymetric survey has been published for Hancock Outflow Lake, so its depth is not documented here.
Stays via Stay22
Stays near Hancock Outflow Lake
Compare lakeside cabins, hotels, and vacation rentals near Hancock Outflow Lake 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 Hancock Outflow Lake are listed below.
Top-rated places to stay near Hancock Outflow Lake
Prices for Oct 16–18, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Florida’s top lakes →
Follow Hancock Outflow Lake’s readings
Email me when new measurements post for this lake. Updates stay free.
Or email
Fishing Hancock Outflow Lake
Water Quality Trend: Worsening
Based on 5 years of monitoring (2020–2025).
Water clarity
Stable5 years
Phosphorus
Worsening+65.33 µg/L/yr5 years
Reservoir Info (USACE NID)
Hancock Outflow Lake 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 · Matched by proximity (0.95 km)
Nearby Lakes in Polk County
Frequently asked questions about Hancock Outflow Lake
Where is Hancock Outflow Lake?
- Hancock Outflow Lake 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 Hancock Outflow Lake?
- Hancock Outflow Lake in Polk County, Florida has water-quality measurements published by Florida DEP, shown here as reported. Water clarity: 0.7 ft visibility. Phosphorus: 478 µg/L. Surface area: 4541 acres.
Is Hancock Outflow Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Hancock Outflow Lake?
- Hancock Outflow Lake typically sits around 83°F at the surface in September, from 9 EPA Water Quality Portal field readings (2023–2025). That is a typical value for the month, not a live reading.
Explore Hancock Outflow Lake across LakeQuality
More lakes in Florida
Other Lakes in Florida
Hypereutrophic Lakes in Florida
Where this data comes from
18 measurements from 1 monitoring station, 2023–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Submitting organization not recorded for these samples18 samples · 2023–2025
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.