Baldwin Lake Northwest Basin is a mesotrophic lake in Cass County, Michigan. Water quality is graded C based on 1 sampling years through 2023. Overall water quality is improving over recent sampling years. The lake supports 25 documented fish species including Blacknose shiner, Blackside darter, and Blackstripe topminnow. Compared to the 22 other monitored lakes in Cass County, Baldwin Lake Northwest Basin ranks #16 for water quality.
Source: EPA Water Quality Portal sampling records, Michigan DNR, last sampled 2023-09-13. Grade methodology: LakeGrade methodology.
Watch Baldwin Lake Northwest Basin water quality
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Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Moderate clarity, visible to about 8 ft. Trophic State Index: 47.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 8 ft | C |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 47 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Baldwin Lake Northwest Basin
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Fish Species
Click a species to see every graded lake where it is documented.
Fishing Baldwin Lake Northwest Basin
Water Quality Trend: ↑ Improving
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +1.57 m/yr | 4 |
| Chlorophyll-a | ↑ Improving | -0.35 µg/L/yr | 3 |
Water Temperature
Baldwin Lake Northwest Basin averages about 60°F at the surface in summer, usually warmest in Aug (about 62°F) and coldest in May (about 54°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 358 field readings (2022–2023) via the EPA Water Quality Portal. See the full Baldwin Lake Northwest Basin water temperature breakdown →
Location
County Ranking
Ranked #16 of 23 lakes in Cass County
Cleaner Lakes Within 30 Miles
Baldwin Lake Northwest Basin holds Grade C. One nearby lake has a higher grade.
Nearby Lakes in Cass County
Explore Baldwin Lake Northwest Basin across LakeGrade
Fish species and top-graded lakes across Michigan
Fish species and best lakes in Cass County
Species activity outlook by water temperature and season
Where to stay at Michigan's top lakes, each with its grade
Moderate nutrients, good water quality
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Other Grade C Lakes in Michigan
St. Joseph County · Clarity: 9.5 ft
St. Joseph County · Clarity: 6 ft
Kalamazoo County · Clarity: 9 ft
Kalamazoo County · Clarity: 8 ft
Van Buren County · Clarity: 8 ft
Kalamazoo County · Clarity: 9.5 ft
Mesotrophic Lakes in Michigan
More records, surveys & data sources
EPA Impairment Status
Baldwin Lake Northwest Basin is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit MI040500011303-05 · Official waterbody report · Matched by proximity (0.92 km)
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Baldwin Lake Northwest Basin under Clean Water Act (NPDES) discharge permits.
- Service Oil CompanyUnion · 1.9 mi away · NPDES MIG080853
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grading methodology based on Metropolitan Council standards
Most recent sample: 2023-09-13
Monitoring stations: 1