Portage Lake
Livingston County, Michigan645 acresView mapDirections
Not Rated: one monitoring station are on record, but they measured water clarity only. LakeQuality’s A–F method grades total phosphorus, total nitrogen, chlorophyll-a, and turbidity; clarity is shown, not scored.
- Impaired · Mercury
- Public access
- Limited data
Portage Lake in Livingston County, Michigan is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 12.5 ft visibility. Surface area: 645.1 acres.
- Clarity
- 12.5 ft
- Area
- 645 acres
- Trend
- ↓ Declining
- Public access
- Yes
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Watch Portage Lake’s letter
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Why Portage Lake has no grade
Portage Lake has monitoring on record from one station, but only water clarity was measured. LakeQuality’s A–F letter uses total phosphorus, total nitrogen, chlorophyll-a, and turbidity against EPA National Lakes Assessment condition classes. With none of those grading measurements on record, Portage Lake is Not Rated — not an F. Its 12.5-foot median from 126 readings collected 2016–2023 is still shown as clarity, but clarity alone cannot earn a letter.
Not Rated is EPA Integrated Reporting Category 3 — insufficient information. Everything below that has been measured is still reported on this page.
Sampling is run by EGLE and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Portage Lake is a 645-acre lake in Livingston County, Michigan. 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.
Source: EPA Water Quality Portal sampling records, EGLE, last sampled 2023-06-01. Grade methodology: LakeQuality methodology.
What Portage Lake is good for
From access and monitoring records, not editorial picks.
- Clear water12.5 ft of visibility
- Boat launch1 documented ramp
Swimming Safety
Not ratedLimited data
The letter is not a swimming clearance. 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 measurements for Portage Lake
These readings exist but are not enough for an A–F grade — see why.
Good clarity, visible to about 12.5 ft. TSI 41.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 12.5 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 41 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 645 acres |
| Public Access | Yes |
No bathymetric survey has been published for Portage Lake, so its depth is not documented here.
Recreation & Access
- Portage LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Portage Lake
Water Quality Trend: ↓ Declining
Based on 9 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | -0.092 m/yr | 9 |
| Phosphorus | ↓ Declining | +0.99 µg/L/yr | 7 |
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)
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.
Graded lakes near Portage Lake
Portage Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Livingston County
Frequently asked questions about Portage Lake
Where is Portage Lake?
- Portage Lake is a lake in Livingston County, Michigan. LakeQuality has not rated this lake (UNRATED) — the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity.
What is the water quality grade for Portage Lake?
- Portage Lake in Livingston County, Michigan is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 12.5 ft visibility. Surface area: 645.1 acres.
Is Portage Lake safe to swim in?
- The letter is not a swimming clearance. 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 Portage Lake?
- Fish species found in Portage Lake include Lake herring. Portage Lake is located in Livingston County, Michigan.
Are there boat ramps on Portage Lake?
- Portage Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Portage Lake. Public access is listed as yes.
Explore Portage Lake across LakeQuality
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Where this data comes from
126 measurements from 1 monitoring station, 2016–2023. Retrieved from the EPA Water Quality Portal on 2026-08-26.
Collected and reported by
- North American Lake Management Society
NALMS126 samples · 2016–2023
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Named boat-access points from the USGS National Boat Ramps inventory