Williams Reservoir
Allen County, OhioView mapDirections
Ohio EPA publishes the water-quality measurements for Williams Reservoir. Here is what has been measured.
- Eutrophic
- Limited data
Ask about Williams Reservoir
Answers come straight from the public measurements and survey records on this page.
Williams Reservoir in Allen County, Ohio has water-quality measurements published by Ohio EPA, shown here as reported. Phosphorus: 39.4 µg/L. Chlorophyll-a (algae): 19.8 µg/L.
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Williams Reservoir is a productive, nutrient-rich eutrophic lake in Allen County, Ohio. Compared to the 6 other monitored lakes in Allen County, Williams Reservoir ranks #4 for water quality.
Source: EPA Water Quality Portal sampling records, Ohio EPA, last sampled 2024-10-08. Grade methodology: LakeQuality methodology.
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 Williams 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 Williams Reservoir
These are the measurements Ohio EPA publishes for Williams 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 39.4 µg/L. Chlorophyll-a 19.8 µg/L. TSI 59.
| Metric | Value | EPA condition class |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 39.4 µg/L | Fair |
| Chlorophyll-a (Algae) | 19.8 µg/L | Fair |
| Trophic State Index (TSI) | 59 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Fishing Williams Reservoir
Nearby Lakes in Allen County
Frequently asked questions about Williams Reservoir
Where is Williams Reservoir?
- Williams Reservoir is a lake in Allen County, Ohio. Its water-quality measurements are published by Ohio EPA and shown on this page as reported.
What is the water quality of Williams Reservoir?
- Williams Reservoir in Allen County, Ohio has water-quality measurements published by Ohio EPA, shown here as reported. Phosphorus: 39.4 µg/L. Chlorophyll-a (algae): 19.8 µg/L.
Is Williams 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
74 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_WQX74 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.