Little Portage Lake
Washtenaw County, MichiganView mapDirections
Clarity, phosphorus, and algae sit in the clean band for this region.
- Mesotrophic
- Impaired · Mercury
- #8 of 8 in the county
- Limited data
Little Portage Lake in Washtenaw County, Michigan has a water quality grade of B (Good). Water clarity: 11 ft visibility. Phosphorus: 14.5 µg/L.
- Clarity
- 11 ft
- Type
- Mesotrophic
- Phosphorus
- 14.5 µg/L
- Trend
- → Stable
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Watch Little Portage Lake’s letter
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Little Portage Lake is a mesotrophic lake in Washtenaw County, Michigan. Water quality is graded B based on 1 sampling years through 2023. Water clarity is improving over recent sampling years. The lake supports 1 documented fish species including Grass pickerel. Compared to the 7 other monitored lakes in Washtenaw County, Little Portage Lake ranks #8 for water quality.
Source: EPA Water Quality Portal sampling records, EGLE, last sampled 2023-09-16. Grade methodology: LakeQuality methodology.
What Little Portage Lake is good for
From access and monitoring records, not editorial picks.
- Clear water11 ft of visibility
Swimming Safety
Grade onlyLimited data
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 B is nutrients and algae, not a swimming clearance. Little Portage Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, pesticides, pFAS, pCBs. Check local advisories before you swim.
Water Quality Grade: B (Good)
Good clarity, visible to about 11 ft. Phosphorus 14.5 µg/L. TSI 43. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 11 ft | Not graded |
| Phosphorus | 14.5 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 43 | Mesotrophic |
Moderate nutrients, good water quality
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Little Portage Lake
Water Quality Trend: → Stable
Based on 8 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.345 m/yr | 8 |
| Phosphorus | ↓ Declining | +1.37 µg/L/yr | 7 |
EPA Impairment Status
Little 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 MI040900050307-23 · Official waterbody report · Matched by proximity (0.2 km)
County Ranking
Ranked #8 of 8 lakes in Washtenaw County
Nearby Lakes in Washtenaw County
Frequently asked questions about Little Portage Lake
Where is Little Portage Lake?
- Little Portage Lake is a lake in Washtenaw County, Michigan. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Little Portage Lake?
- Little Portage Lake in Washtenaw County, Michigan has a water quality grade of B (Good). Water clarity: 11 ft visibility. Phosphorus: 14.5 µg/L.
Is Little Portage Lake safe to swim in?
- The B is nutrients and algae, not a swimming clearance. Little Portage Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, pesticides, pFAS, pCBs. Check local advisories before you swim.
What fish are in Little Portage Lake?
- Fish species found in Little Portage Lake include Grass pickerel. Little Portage Lake is located in Washtenaw County, Michigan.
Explore Little Portage Lake across LakeQuality
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Where this data comes from
65 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_MICORPS65 samples · 2016–2023
Analytical methods
- Phosphorus by Colorimetry
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