Alligator Lake
Columbia County, Florida116 acresView mapDirections
Florida DEP publishes the water-quality measurements for Alligator Lake. Here is what has been measured.
- Eutrophic
- Impaired · Algal growth
- Public access
- Limited data
Alligator Lake in Columbia County, Florida has water-quality measurements published by Florida DEP, shown here as reported. Water clarity: 3 ft visibility. Phosphorus: 58 µg/L. Surface area: 116 acres.
Alligator Lake is a 116-acre productive, nutrient-rich eutrophic lake in Columbia County, Florida. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 2 other monitored lakes in Columbia County, Alligator Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, FDEP, last sampled 2023-08-02. Methodology: how these readings are compared.
What Alligator Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
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. Alligator Lake 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 Alligator 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 Alligator Lake
These are the measurements Florida DEP publishes for Alligator 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 3 ft of visibility. Phosphorus 58 µg/L. TSI 62.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 3ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 58µg/L | Fair 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. | 62 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Alligator Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
116 acres
Public access
Yes
Listed by Florida DEP
No bathymetric survey has been published for Alligator Lake, so its depth is not documented here.
Recreation & Access
- Alligator Lake SouthPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
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Fishing Alligator Lake
Water Quality Trend: Worsening
Based on 4 years of monitoring (2021–2024).
Water clarity
Worsening4 years
Phosphorus
Worsening+7.59 µg/L/yr4 years
Reservoir Info (USACE NID)
Alligator Lake is a man-made reservoir impounded by the Alligator Lake Dam, built primarily for recreation on the Alligator Lake; earth-type dam, 7 ft tall and 3,315 ft long.
- Surface area
- 116 ac
- Normal storage
- 1,932 ac-ft
- Max storage
- 1,932 ac-ft
- Hazard class
- Undetermined
- Owner
- COLUMBIA COUNTY
Source: USACE National Inventory of Dams, NID ID FL59001 · Operator website
EPA Impairment Status
Alligator Lake 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 FL3516A · Official waterbody report
Nearby Lakes in Columbia County
Frequently asked questions about Alligator Lake
Where is Alligator Lake?
- Alligator Lake is a lake in Columbia County, Florida. Its water-quality measurements are published by Florida DEP and shown on this page as reported.
What is the water quality of Alligator Lake?
- Alligator Lake in Columbia County, Florida has water-quality measurements published by Florida DEP, shown here as reported. Water clarity: 3 ft visibility. Phosphorus: 58 µg/L. Surface area: 116 acres.
Is Alligator Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Alligator Lake 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.
Are there boat ramps on Alligator Lake?
- Alligator Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Alligator Lake South. Public access is listed as yes.
Can I fish at Alligator Lake?
- Alligator Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. 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.
Explore Alligator Lake across LakeQuality
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Where this data comes from
10 measurements from 1 monitoring station, 2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Submitting organization not recorded for these samples10 samples · 2023
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
Named boat-access points from the USGS National Boat Ramps inventory