Seminole-Onora Lake
Seminole County, FloridaView mapDirections
Florida DEP publishes the water-quality measurements for Seminole-Onora Lake. Here is what has been measured.
- Limited data
Seminole-Onora Lake in Seminole County, Florida has water-quality measurements published by Florida DEP, shown here as reported. Water clarity: 6.8 ft visibility. Phosphorus: 20.5 µg/L.
Seminole-Onora Lake is a lake in Seminole County, Florida. Overall water quality is declining over recent sampling years.
Source: EPA Water Quality Portal sampling records, FDEP, last sampled 2023-07-13. Methodology: how these readings are compared.
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Seminole-Onora 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 Seminole-Onora Lake
These are the measurements Florida DEP publishes for Seminole-Onora Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Moderate clarity, visible to about 6.8 ft. Phosphorus 20.5 µg/L. TSI 49.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 6.8ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 20.5µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| 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. | 49 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
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Stays near Seminole-Onora Lake
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Fishing Seminole-Onora Lake
Water Quality Trend: Worsening
Based on 5 years of monitoring (2020–2024).
Water clarity
Stable5 years
Phosphorus
Worsening+2.3 µg/L/yr5 years
Nearby Lakes in Seminole County
Frequently asked questions about Seminole-Onora Lake
Where is Seminole-Onora Lake?
- Seminole-Onora Lake is a lake in Seminole County, Florida. Its water-quality measurements are published by Florida DEP and shown on this page as reported.
What is the water quality of Seminole-Onora Lake?
- Seminole-Onora Lake in Seminole County, Florida has water-quality measurements published by Florida DEP, shown here as reported. Water clarity: 6.8 ft visibility. Phosphorus: 20.5 µg/L.
Is Seminole-Onora Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Explore Seminole-Onora Lake across LakeQuality
Planning a trip around Canaveral?
Seminole-Onora Lake is about 30 miles from Canaveral National Seashore. Crowds there swing hard by season, so the month you pick changes both how busy the park is and what lodging costs.
Best time to visit Canaveral →More lakes in Florida
Other Lakes in Florida
Mesotrophic Lakes in Florida
Where this data comes from
4 measurements from 2 monitoring stations, 2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- FLORIDA LAKEWATCH
21FLKWAT_WQX4 samples · 2023
Monitoring station identifiers (2)
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.