Perch Lake
Perch Lake in St. Louis County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 6.6 ft visibility. Phosphorus: 21 µg/L. Chlorophyll-a (algae): 11.5 µg/L. Maximum depth: 13 ft. Surface area: 100.14 acres.
- Clarity
- 6.6 ft
- Max depth
- 13 ft
- Area
- 100 acres
- Public access
- Yes
Next lake in St. Louis County
Why Perch Lake has no grade
We grade a lake only when its monitoring record clears the evidence bar: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Perch Lake, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). Sampling here has recorded water clarity, phosphorus and algae (chlorophyll-a).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by MPCA and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Perch Lake is a 100-acre lake in St. Louis County, Minnesota with a maximum depth of 13 feet. The lake supports 6 documented fish species including bluegill, hybrid sunfish, and northern pike. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-08-16. Grade methodology: LakeGrade methodology.
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Perch Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Murky, only visible to about 6.6 ft. Phosphorus level: 21 µg/L. Chlorophyll-a: 11.5 µg/L. Trophic State Index: 51.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 6.6 ft | Not graded |
| Phosphorus | 21 µg/L | Not graded |
| Chlorophyll-a (Algae) | 11.5 µg/L | Not graded |
| Trophic State Index (TSI) | 51 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Perch Lake
Compare lakeside cabins, hotels, and vacation rentals near Perch Lake in St. Louis County, Minnesota — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Perch Lake
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Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 13 ft |
| Surface Area | 100 acres |
| Shoreline Length | 3.3 mi |
| Littoral Zone | 100% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Birch Lake (West)Public
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Perch Lake
EPA Impairment Status
Perch 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 MN69-0058-00 · Official waterbody report
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Perch Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Babbitt WwtpBabbitt · 4.3 mi away · NPDES MN0020656Recent violation
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 Perch Lake
Perch Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in St. Louis County
Frequently asked questions about Perch Lake
What is the water quality grade for Perch Lake?
- Perch Lake in St. Louis County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 6.6 ft visibility. Phosphorus: 21 µg/L. Chlorophyll-a (algae): 11.5 µg/L. Maximum depth: 13 ft. Surface area: 100.14 acres.
Is Perch Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Perch Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Algae concentration (chlorophyll-a) is 11.5 µg/L. Always check local health department advisories before swimming.
How deep is Perch Lake?
- Perch Lake has a maximum depth of 13 feet. The lake covers 100.14 acres.
What fish are in Perch Lake?
- Fish species found in Perch Lake include bluegill, hybrid sunfish, northern pike, walleye, white sucker, yellow perch. Perch Lake is located in St. Louis County, Minnesota.
Are there boat ramps on Perch Lake?
- Perch Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Birch Lake (West). Public access is listed as yes.
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Where this data comes from
9 measurements from 1 monitoring station, 2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA9 samples · 2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
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)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory