Unnamed Lake
Unnamed Lake in Polk County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 2 ft visibility. Phosphorus: 72 µg/L. Chlorophyll-a (algae): 51.4 µg/L.
- Clarity
- 2 ft
- Type
- Eutrophic
- Trend
- ↑ Improving
- Public access
- No
Grade F measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Unnamed Lake →
Next lake in Polk County
Unnamed Lake is a productive, nutrient-rich eutrophic lake in Polk County, Minnesota. Water quality is graded F based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. Limited fish-species data available. No public access — the lake is private or restricted. Compared to the 18 other monitored lakes in Polk County, Unnamed Lake ranks #16 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-24. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyAlgae risk
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.
Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom
Water Quality Grade: F (Algae-prone)
Very murky, less than 2 ft of visibility. Phosphorus level: 72 µg/L. Chlorophyll-a: 51.4 µg/L. Trophic State Index: 67.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2 ft | Not graded |
| Phosphorus | 72 µg/L | Poor |
| Chlorophyll-a (Algae) | 51.4 µg/L | Poor |
| Trophic State Index (TSI) | 67 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Unnamed Lake
Compare lakeside cabins, hotels, and vacation rentals near Unnamed Lake in Polk 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. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around Unnamed Lake are listed below.
Top-rated places to stay near Unnamed Lake
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
Fishing Unnamed Lake
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.407 m/yr | 6 |
| Phosphorus | ↓ Declining | +0.53 µg/L/yr | 6 |
| Chlorophyll-a | ↑ Improving | -0.09 µg/L/yr | 6 |
EPA Impairment Status
Unnamed Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN60-0236-00 · Official waterbody report
County Ranking
Ranked #16 of 19 lakes in Polk County
Nearby Lakes With Higher Grades
Unnamed Lake holds Grade F. 3 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Polk County
Frequently asked questions about Unnamed Lake
What is the water quality grade for Unnamed Lake?
- Unnamed Lake in Polk County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 2 ft visibility. Phosphorus: 72 µg/L. Chlorophyll-a (algae): 51.4 µg/L.
Is Unnamed Lake safe to swim in?
- Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom. Unnamed Lake has a water quality grade of F (Algae-prone). Algae concentration (chlorophyll-a) is 51.4 µg/L. Always check local health department advisories before swimming.
Explore Unnamed Lake across LakeGrade
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Where this data comes from
51 measurements from 4 monitoring stations, 2022–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA50 samples · 2023–2025 - Minnesota Department of Agriculture - Pesticide Monitoring
MNDA_PESTICIDE1 sample · 2022
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Phosphorus by Colorimetry
- 2120 B ~ Color in Water by Visual Comparison
Monitoring station identifiers (4)
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