Perry County, Ohio · Water Quality Report Card
St Joseph Lake
St Joseph Lake in Perry County, Ohio has a water quality grade of F (Very Poor). Phosphorus: 58.9 µg/L. Chlorophyll-a (algae): 58.7 µg/L.
- Mean depth
- ~17 ft est.
- Type
- Hypereutrophic
St Joseph Lake is a highly nutrient-loaded hypereutrophic lake in Perry County, Ohio with an estimated average depth of about 17 feet. Water quality is graded F based on 2 sampling years through 2022. Compared to the 2 other monitored lakes in Perry County, St Joseph Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Ohio EPA, last sampled 2022-10-24. Grade methodology: LakeGrade methodology.
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Swimming Safety
Avoid swimming, very poor water quality, potential algae toxins
Water Quality Grade: F (Very Poor)
No clarity data. Phosphorus level: 58.9 µg/L. Chlorophyll-a: 58.7 µg/L. Trophic State Index: 67.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No data | |
| Phosphorus | 58.9 µg/L | Poor |
| Chlorophyll-a (Algae) | 58.7 µg/L | Poor |
| Trophic State Index (TSI) | 67 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Lake Details
| Characteristic | Value |
|---|---|
| Average Depth | ~17 ft est. |
Depth marked “est.” is a modeled estimate from HydroLAKES, not a measured survey. Ohio has not published bathymetry for St Joseph Lake.
Where to stay near St Joseph Lake
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Fishing St Joseph Lake
Location
County Ranking
Ranked #3 of 3 lakes in Perry County
Nearby Lakes in Perry County
Explore St Joseph Lake across LakeGrade
More Ohio Lake Rankings
Other Grade F Lakes in Ohio
Hypereutrophic Lakes in Ohio
More records, surveys & data sources
EPA Impairment Status
St Joseph Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit OH050302040101 · Official waterbody report · Matched by proximity (1.01 km)
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Where this data comes from
28 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_WQX28 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)
Grade thresholds come from the U.S. EPA National Lakes Assessment 2022 Technical Support Document (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated.
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion
Most recent sample: 2022-10-24
Monitoring stations: 1