Fremont Reservoir
Sandusky County, OhioView mapDirections
Ohio EPA publishes the water-quality measurements for Fremont Reservoir. Here is what has been measured.
- Eutrophic
- Limited data
Fremont Reservoir in Sandusky County, Ohio has water-quality measurements published by Ohio EPA, shown here as reported. Phosphorus: 50.1 µg/L. Chlorophyll-a (algae): 9.5 µg/L.
Fremont Reservoir is a productive, nutrient-rich eutrophic lake in Sandusky County, Ohio.
Source: EPA Water Quality Portal sampling records, Ohio EPA, last sampled 2022-09-26. Methodology: how these readings are compared.
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 Fremont Reservoir is safe to swim in today is a call for the Ohio Environmental Protection Agency and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Fremont Reservoir
These are the measurements Ohio EPA publishes for Fremont Reservoir, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. Phosphorus 50.1 µg/L. Chlorophyll-a 9.5 µg/L. TSI 57.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer. | |
| Total phosphorus | 50.1µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 9.5µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 57 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
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Frequently asked questions about Fremont Reservoir
Where is Fremont Reservoir?
- Fremont Reservoir is a lake in Sandusky County, Ohio. Its water-quality measurements are published by Ohio EPA and shown on this page as reported.
What is the water quality of Fremont Reservoir?
- Fremont Reservoir in Sandusky County, Ohio has water-quality measurements published by Ohio EPA, shown here as reported. Phosphorus: 50.1 µg/L. Chlorophyll-a (algae): 9.5 µg/L.
Is Fremont Reservoir safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
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Where this data comes from
58 measurements from 1 monitoring station, 2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Division of Surface water (Ohio)
21OHIO_WQX58 samples · 2022
Analytical methods
- Total Phosphorus After Block Digestion
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- 2130 B ~ Nephelometric Method
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.