First Sister Lake
Washtenaw County, WisconsinLimited DataEutrophic
First Sister Lake is a productive, nutrient-rich eutrophic lake in Washtenaw County, MI. Water quality is graded F based on 1 sampling years through 2022. The lake supports 3 documented fish species including Bluegill, Green sunfish, and Yellow bullhead. Compared to the 16 other monitored lakes in Washtenaw County, First Sister Lake ranks #15 for water quality.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2022-03-20. Grade methodology: LakeGrade methodology.
Swimming Safety
Avoid swimming, very poor water quality, potential algae toxins
Water Quality Grade: F, Very Poor
Very murky, less than 3 ft of visibility. Trophic State Index: 61.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 61 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Fish Species
Click a species to see all Wisconsin and Minnesota lakes where it is found.
→ Best fishing times for First Sister Lake (14-day solunar calendar)
→ Is it safe to eat fish from First Sister Lake? (mercury & PFAS guide)
→ First Sister Lake fishing regulations (limits, seasons, special rules)
Location
County Ranking
Ranked #15 of 17 lakes in Washtenaw County
Cleaner Lakes Within 30 Miles
First Sister Lake holds Grade F. One nearby lake has a higher grade.
See full comparison →Nearby Lakes in Washtenaw County
More Wisconsin Lake Rankings
Other Grade F Lakes in Wisconsin
Ottawa County · Clarity: 3 ft
Berrien County · Clarity: 3 ft
Berrien County · Clarity: 3 ft
Genesee County · Clarity: 1.8 ft
Hillsdale County · Clarity: 3.3 ft
Hillsdale County · Clarity: 3.3 ft
Eutrophic Lakes in Wisconsin
EPA Impairment Status
First Sister Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MI040900050308-02 · Official waterbody report · Matched by proximity (0.52 km)
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Grading methodology based on Metropolitan Council standards
Most recent sample: 2022-03-20
Monitoring stations: 1