Highlands-Grassy Lake
Highlands County, FloridaView mapDirections
Florida DEP publishes the water-quality measurements for Highlands-Grassy Lake. Here is what has been measured.
- Mesotrophic
- Impaired · Mercury
Highlands-Grassy Lake in Highlands County, Florida has water-quality measurements published by Florida DEP, shown here as reported. Water clarity: 5 ft visibility. Phosphorus: 12.5 µg/L.
Highlands-Grassy Lake is a mesotrophic lake in Highlands County, Florida. Water clarity is declining over recent sampling years. Compared to the 72 other monitored lakes in Highlands County, Highlands-Grassy Lake ranks #55 for water quality.
Source: EPA Water Quality Portal sampling records, FDEP, last sampled 2024-11-21. Methodology: how these readings are compared.
Swimming conditions
Readings onlyLow algae
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. Highlands-Grassy Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
Whether Highlands-Grassy 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 Highlands-Grassy Lake
These are the measurements Florida DEP publishes for Highlands-Grassy Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 5 ft. Phosphorus 12.5 µg/L. TSI 47.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 12.5µg/L | Good 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. | 47 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
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Fishing Highlands-Grassy Lake
Water quality readings over time
2 seasons of samples on record (2023–2024). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Worsening2 years
Phosphorus
Improving-2 µg/L/yr2 years
EPA Impairment Status
Highlands-Grassy Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 4A).
Causes of impairment
Designated uses not supporting: Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit FL1932A · Official waterbody report
Nearby Lakes in Highlands County
Frequently asked questions about Highlands-Grassy Lake
Where is Highlands-Grassy Lake?
- Highlands-Grassy Lake is a lake in Highlands County, Florida. Its water-quality measurements are published by Florida DEP and shown on this page as reported.
What is the water quality of Highlands-Grassy Lake?
- Highlands-Grassy Lake in Highlands County, Florida has water-quality measurements published by Florida DEP, shown here as reported. Water clarity: 5 ft visibility. Phosphorus: 12.5 µg/L.
Is Highlands-Grassy Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Highlands-Grassy Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
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Where this data comes from
94 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_WQX94 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.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database