Devils Lake
Lenawee County, MichiganView mapDirections
Clarity, phosphorus, and algae all sit in the cleanest band for this region.
- Mesotrophic
- Impaired · Mercury
- #3 of 5 in the county
Devils Lake in Lenawee County, Michigan has a water quality grade of A (Excellent). Water clarity: 11 ft visibility. Phosphorus: 9 µg/L. Chlorophyll-a (algae): 2.2 µg/L.
- Clarity
- 11 ft
- Typical in September
- 63°F
- Type
- Mesotrophic
- Phosphorus
- 9 µg/L
- Chlorophyll-a
- 2.2 µg/L
- Trend
- ↓ Declining
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Watch Devils Lake’s letter
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Devils Lake is a mesotrophic lake in Lenawee County, Michigan. Water quality is graded A based on 2 sampling years through 2023. Overall water quality is declining over recent sampling years. The lake supports 3 documented fish species including Bluegill, Smallmouth bass, and Yellow perch. Compared to the 4 other monitored lakes in Lenawee County, Devils Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, EGLE, last sampled 2023-09-21. Grade methodology: LakeQuality methodology.
What Devils Lake is good for
From access and monitoring records, not editorial picks.
- Clear water11 ft of visibility
- Fishing3 species recorded
Swimming Safety
Grade onlyLow algae
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
The A is nutrients and algae, not a swimming clearance. Devils Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
Water Quality Grade: A (Excellent)
Good clarity, visible to about 11 ft. Phosphorus 9 µg/L. Chlorophyll-a 2.2 µg/L. TSI 39. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 11 ft | Not graded |
| Phosphorus | 9 µg/L | Good |
| Chlorophyll-a (Algae) | 2.2 µg/L | Good |
| Trophic State Index (TSI) | 39 | Mesotrophic |
Moderate nutrients, good water quality
Water Temperature
Devils Lake typically sits around 63°F at the surface in September. Summer average is about 62°F. Usually warmest in Aug (about 64°F) and coldest in May (about 55°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 1,177 field readings (2010–2023) via the EPA Water Quality Portal. See the full Devils Lake water temperature breakdown →
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Devils Lake
Water Quality Trend: ↓ Declining
Based on 7 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.08 m/yr | 7 |
| Phosphorus | ↓ Declining | +1 µg/L/yr | 7 |
| Chlorophyll-a | ↓ Declining | +0.43 µg/L/yr | 7 |
EPA Impairment Status
Devils 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 MI041000060101-02 · Official waterbody report · Matched by proximity (0.44 km)
County Ranking
Ranked #3 of 5 lakes in Lenawee County
Nearby Lakes in Lenawee County
Frequently asked questions about Devils Lake
Where is Devils Lake?
- Devils Lake is a lake in Lenawee County, Michigan. LakeQuality grades it A for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Devils Lake?
- Devils Lake in Lenawee County, Michigan has a water quality grade of A (Excellent). Water clarity: 11 ft visibility. Phosphorus: 9 µg/L. Chlorophyll-a (algae): 2.2 µg/L.
Is Devils Lake safe to swim in?
- The A is nutrients and algae, not a swimming clearance. Devils Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
What is the water temperature of Devils Lake?
- Devils Lake typically sits around 63°F at the surface in September, from 1,177 EPA Water Quality Portal field readings (2010–2023). That is a typical value for the month, not a live reading.
What fish are in Devils Lake?
- Fish species found in Devils Lake include Bluegill, Smallmouth bass, Yellow perch. Devils Lake is located in Lenawee County, Michigan.
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Where this data comes from
73 measurements from 1 monitoring station, 2016–2023. Retrieved from the EPA Water Quality Portal on 2026-08-26.
Collected and reported by
- Michigan EGLE - MiCorps
21MICH_MICORPS73 samples · 2016–2023
Analytical methods
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database