Grey Cloud Slough Lake
Grey Cloud Slough Lake in Washington County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 3.3 ft visibility.
- Clarity
- 3.3 ft
- Public access
- Yes
Next lake in Washington County
Why Grey Cloud 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 Grey Cloud Slough Lake, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). Sampling here has recorded water clarity, but not 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.
Grey Cloud Slough Lake is a lake in Washington County, Minnesota. Limited fish-species data available. Public access is available.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2023-10-05. 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 Grey Cloud Slough Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Very murky, less than 3.3 ft of visibility. Trophic State Index: 60.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.3 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 60 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Grey Cloud Slough Lake
Compare lakeside cabins, hotels, and vacation rentals near Grey Cloud Slough Lake in Washington 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.
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Fishing Grey Cloud Slough Lake
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Grey Cloud Slough Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Public Water Access Sites — Grey Cloud SloughPublic Water Access Sites · MN DNR LakeFinder
Regulated Pollution Sources Nearby
10 EPA-permitted facilities operate within about 5 miles of Grey Cloud Slough Lake under Clean Water Act (NPDES) discharge permits, including 2 classified by the EPA as major dischargers. 1 facility has a reported Clean Water Act violation in the past three years.
- Flint Hills Resources Pine Bend LlcRosemount · 3.4 mi away · NPDES MN0000418MajorRecent violation
- Mcws-RosemountRosemount · 3.8 mi away · NPDES MN0025488Major
- Aggregate Industries Inc - Nelson PlantGrey Cloud Island, Township Of · 0.9 mi away · NPDES MN0001309
- Larson QuarrySaint Paul Park · 1.3 mi away · NPDES MN0030473
- Minnesota Pipeline Co-HydroCottage Grove · 2.2 mi away · NPDES MN0056472
- Cf Industries Distribution Facilities Llc - Pine Bend TerminalRosemount · 2.7 mi away · NPDES MN0069418
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 Grey Cloud Slough Lake
Grey Cloud Slough Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Washington County
Frequently asked questions about Grey Cloud Slough Lake
What is the water quality grade for Grey Cloud Slough Lake?
- Grey Cloud Slough Lake in Washington County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 3.3 ft visibility.
Is Grey Cloud Slough Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Grey Cloud Slough Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
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Where this data comes from
3 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
MNPCA3 samples · 2023
Analytical methods
- Field measurement/observation, generic method
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)