Ottawa R Lake
Allen County, OhioView mapDirections
Ohio EPA publishes the water-quality measurements for Ottawa R Lake. Here is what has been measured.
- Mesotrophic
- Impaired · Cause unknown
- Limited data
Ask about Ottawa R Lake
Answers come straight from the public measurements and survey records on this page.
Ottawa R Lake in Allen County, Ohio has water-quality measurements published by Ohio EPA, shown here as reported. Phosphorus: 207 µg/L. Chlorophyll-a (algae): 2.1 µg/L.
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Ottawa R Lake is a mesotrophic lake in Allen County, Ohio. Compared to the 6 other monitored lakes in Allen County, Ottawa R Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Ohio EPA, last sampled 2024-09-12. Grade methodology: LakeQuality methodology.
Swimming conditions
Readings onlyBacteria advisory
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. Ottawa R Lake is listed impaired under Clean Water Act §303(d) (IR 5) for cause unknown, habitat alterations, nutrients (phosphorus, nitrogen), oxygen depletion (low DO), pathogens (E. coli, fecal). Check local advisories before you swim.
Whether Ottawa R Lake 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 Ottawa R Lake
These are the measurements Ohio EPA publishes for Ottawa R Lake, 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 207 µg/L. Chlorophyll-a 2.1 µg/L. TSI 60.
| Metric | Value | EPA condition class |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 207 µg/L | Poor |
| Chlorophyll-a (Algae) | 2.1 µg/L | Good |
| Trophic State Index (TSI) | 60 | Mesotrophic |
Moderate nutrients, good water quality
Fishing Ottawa R Lake
EPA Impairment Status
Ottawa R 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 OH041000070402 · Official waterbody report · Matched by proximity (2.14 km)
Nearby Lakes in Allen County
Frequently asked questions about Ottawa R Lake
Where is Ottawa R Lake?
- Ottawa R Lake 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 Ottawa R Lake?
- Ottawa R Lake in Allen County, Ohio has water-quality measurements published by Ohio EPA, shown here as reported. Phosphorus: 207 µg/L. Chlorophyll-a (algae): 2.1 µg/L.
Is Ottawa R Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Ottawa R Lake is listed impaired under Clean Water Act §303(d) (IR 5) for cause unknown, habitat alterations, nutrients (phosphorus, nitrogen), oxygen depletion (low DO), pathogens (E. coli, fecal). Check local advisories before you swim.
Explore Ottawa R Lake across LakeQuality
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Where this data comes from
14 measurements from 2 monitoring stations, 2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Division of Surface water (Ohio)
21OHIO_WQX14 samples · 2024
Analytical methods
- Total Phosphorus After Block Digestion
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
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.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database