Grossman Slough Lake
Grossman Slough Lake in Stevens County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 2.3 ft visibility. Phosphorus: 708 µg/L. Chlorophyll-a (algae): 3.8 µg/L.
- Clarity
- 2.3 ft
Next lake in Stevens County
Why Grossman Slough 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 Grossman Slough 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.
Grossman Slough Lake is a lake in Stevens County, Minnesota.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2023-08-09. Grade methodology: LakeGrade methodology.
Watch Grossman Slough Lake water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Grossman Slough Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Very murky, less than 2.3 ft of visibility. Phosphorus level: 708 µg/L. Chlorophyll-a: 3.8 µg/L. Trophic State Index: 69.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.3 ft | Not graded |
| Phosphorus | 708 µg/L | Not graded |
| Chlorophyll-a (Algae) | 3.8 µg/L | Not graded |
| Trophic State Index (TSI) | 69 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Grossman Slough Lake
Compare lakeside cabins, hotels, and vacation rentals near Grossman Slough Lake in Stevens 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 Grossman Slough Lake
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Minnesota’s top lakes →
Fishing Grossman Slough Lake
Graded lakes near Grossman Slough Lake
Grossman Slough Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Stevens County
Frequently asked questions about Grossman Slough Lake
What is the water quality grade for Grossman Slough Lake?
- Grossman Slough Lake in Stevens County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 2.3 ft visibility. Phosphorus: 708 µg/L. Chlorophyll-a (algae): 3.8 µg/L.
Is Grossman Slough Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Grossman Slough Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Algae concentration (chlorophyll-a) is 3.8 µg/L. Always check local health department advisories before swimming.
Explore Grossman Slough Lake across LakeGrade
Fish species and top-graded lakes across Minnesota
Fish species and best lakes in Stevens County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its grade
Minnesota's cleanest and most-polluted lakes, ranked
More Minnesota Lake Rankings
State Parks Near Grossman Slough Lake
Other Lakes in Minnesota
Eutrophic Lakes in Minnesota
Where this data comes from
4 measurements from 1 monitoring station, 2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA4 samples · 2023
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- 2120 B ~ Color in Water by Visual Comparison
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.