Portage Lake South Basin; Dexter Township
Washtenaw County, WisconsinLimited DataMesotrophic
Portage Lake South Basin; Dexter Township is a mesotrophic lake in Washtenaw County, MI. Water quality is graded B based on 1 sampling years through 2023. The lake supports 26 documented fish species including Blackstripe topminnow, Bluegill, and Bluntnose minnow. Compared to the 16 other monitored lakes in Washtenaw County, Portage Lake South Basin; Dexter Township ranks #4 for water quality.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2023-09-15. Grade methodology: LakeGrade methodology.
Swimming Safety
Good for swimming, clear water with low algae levels
Water Quality Grade: B, Good
Good clarity, visible to about 13 ft. Trophic State Index: 40.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 13 ft | B |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 40 | Mesotrophic |
Moderate nutrients, good water quality
Fish Species
Click a species to see all Wisconsin and Minnesota lakes where it is found.
→ Best fishing times for Portage Lake South Basin; Dexter Township (14-day solunar calendar)
→ Is it safe to eat fish from Portage Lake South Basin; Dexter Township? (mercury & PFAS guide)
→ Portage Lake South Basin; Dexter Township fishing regulations (limits, seasons, special rules)
Location
County Ranking
Ranked #4 of 17 lakes in Washtenaw County
Cleaner Lakes Within 30 Miles
Portage Lake South Basin; Dexter Township holds Grade B. One nearby lake has a higher grade.
See full comparison →Nearby Lakes in Washtenaw County
More Wisconsin Lake Rankings
Other Grade B Lakes in Wisconsin
Lapeer County · Clarity: 9.5 ft
Livingston County · Clarity: 13 ft
Manistee County · Clarity: 11 ft
Lake County · Clarity: 14 ft
Cass County · Clarity: 10.5 ft
Genesee County · Clarity: 10 ft
Mesotrophic Lakes in Wisconsin
EPA Impairment Status
Portage Lake South Basin; Dexter Township 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 MI040900050307-14 · Official waterbody report · Matched by proximity (1.05 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: 2023-09-15
Monitoring stations: 1