Marysville Upground Reservoir
Union County, OhioView mapDirections
Ohio EPA publishes the water-quality measurements for Marysville Upground Reservoir. Here is what has been measured.
- Mesotrophic
- Limited data
Marysville Upground Reservoir in Union County, Ohio has water-quality measurements published by Ohio EPA, shown here as reported. Phosphorus: 39.7 µg/L. Chlorophyll-a (algae): 6.2 µg/L.
Marysville Upground Reservoir is a mesotrophic lake in Union County, Ohio.
Source: EPA Water Quality Portal sampling records, Ohio EPA, last sampled 2024-08-13. 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 Marysville Upground 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 Marysville Upground Reservoir
These are the measurements Ohio EPA publishes for Marysville Upground 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 39.7 µg/L. Chlorophyll-a 6.2 µg/L. TSI 53.
| 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 | 39.7µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | 6.2µg/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. | 53 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
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Frequently asked questions about Marysville Upground Reservoir
Where is Marysville Upground Reservoir?
- Marysville Upground Reservoir is a lake in Union County, Ohio. Its water-quality measurements are published by Ohio EPA and shown on this page as reported.
What is the water quality of Marysville Upground Reservoir?
- Marysville Upground Reservoir in Union County, Ohio has water-quality measurements published by Ohio EPA, shown here as reported. Phosphorus: 39.7 µg/L. Chlorophyll-a (algae): 6.2 µg/L.
Is Marysville Upground Reservoir safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Explore Marysville Upground Reservoir across LakeQuality
More lakes in Ohio
Mesotrophic Lakes in Ohio
Where this data comes from
18 measurements from 1 monitoring station, 2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Division of Surface water (Ohio)
21OHIO_WQX18 samples · 2024
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.