Portage Lake is a mesotrophic lake in Livingston County, Michigan. Water quality is graded B based on 1 sampling years through 2023. Overall water quality is declining over recent sampling years. The lake supports 1 documented fish species including Lake herring. Public access is available with 1 public boat landing. Compared to the 19 other monitored lakes in Livingston County, Portage Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Michigan DNR, last sampled 2023-06-01. Grade methodology: LakeGrade methodology.
Watch Portage Lake water quality
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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
Where to stay near Portage Lake
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Fish Species
Click a species to see every graded lake where it is documented.
Fishing Portage Lake
Water Quality Trend: ↓ Declining
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.457 m/yr | 5 |
Recreation & Access
Location
County Ranking
Ranked #3 of 20 lakes in Livingston County
Nearby Lakes in Livingston County
Explore Portage Lake across LakeGrade
Fish species and top-graded lakes across Michigan
Fish species and best lakes in Livingston 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
Michigan's cleanest and most-polluted lakes, ranked
More Michigan Lake Rankings
Other Grade B Lakes in Michigan
Washtenaw County · Clarity: 13 ft
Washtenaw County · Clarity: 11 ft
Washtenaw County · Clarity: 12 ft
Washtenaw County · Clarity: 11 ft
Washtenaw County · Clarity: 11.5 ft
Washtenaw County · Clarity: 12 ft
Mesotrophic Lakes in Michigan
More records, surveys & data sources
EPA Impairment Status
Portage 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 MI040900050307-14 · Official waterbody report · Matched by proximity (0.4 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 Portage Lake under Clean Water Act (NPDES) discharge permits.
- Mcpherson Oil CoPinckney · 2.7 mi away · NPDES MIG080973
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
Public boat-access points from the USGS National Boat Ramps inventory
Most recent sample: 2023-06-01
Monitoring stations: 1