Wilmes Lake
Wilmes Lake in Washington County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 3.5 ft visibility. Phosphorus: 66.5 µg/L. Chlorophyll-a (algae): 31 µg/L.
- Clarity
- 3.5 ft
- Typical in August
- 64°F
- Type
- Eutrophic
- Public access
- No
- Ice-out
- Mar 27
Grade F measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Wilmes Lake →
Next lake in Washington County
Wilmes Lake is a productive, nutrient-rich eutrophic lake in Washington County, Minnesota. Water quality is graded F based on 2 sampling years through 2024. Limited fish-species data available. No public access — the lake is private or restricted. Compared to the 74 other monitored lakes in Washington County, Wilmes Lake ranks #74 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-10-22. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLimited data
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)
Murky, only visible to about 3.5 ft. Phosphorus level: 66.5 µg/L. Chlorophyll-a: 31 µg/L. Trophic State Index: 63.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.5 ft | Not graded |
| Phosphorus | 66.5 µg/L | Poor |
| Chlorophyll-a (Algae) | 31 µg/L | Poor |
| Trophic State Index (TSI) | 63 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Wilmes Lake
Compare lakeside cabins, hotels, and vacation rentals near Wilmes 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. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around Wilmes Lake are listed below.
Top-rated places to stay near Wilmes Lake
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
Water Temperature
Wilmes Lake typically sits around 64°F at the surface in August. Summer average is about 64°F. Usually warmest in Jul (about 66°F) and coldest in Apr (about 44°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 158 field readings (2010–2024) via the EPA Water Quality Portal. See the full Wilmes Lake water temperature breakdown →
Fishing Wilmes 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.
Ice Season
Historical ice data from Minnesota DNR (4 observations).
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2016-03-15 (2016) | 2008-04-20 (2008) |
| Ice-In | 2006-11-30 (2006) | 2006-11-30 (2006) |
Most recent ice-out: 2016-03-15
EPA Impairment Status
Wilmes Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit MN82-0090-00 · Official waterbody report
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Wilmes Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 1 facility has a reported Clean Water Act violation in the past three years.
- Wilmes Lake Alum Treatment FacilityWoodbury · 0.6 mi away · NPDES MN0071749MajorRecent 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.
County Ranking
Ranked #74 of 75 lakes in Washington County
Nearby Lakes With Higher Grades
Wilmes Lake holds Grade F. One nearby lake has a higher nutrient-and-algae grade — useful for a swim day, not a reason to skip lodging here.
Nearby Lakes in Washington County
Frequently asked questions about Wilmes Lake
What is the water quality grade for Wilmes Lake?
- Wilmes Lake in Washington County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 3.5 ft visibility. Phosphorus: 66.5 µg/L. Chlorophyll-a (algae): 31 µg/L.
Is Wilmes 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. Wilmes Lake has a water quality grade of F (Algae-prone). Algae concentration (chlorophyll-a) is 31 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Wilmes Lake?
- Wilmes Lake typically sits around 64°F at the surface in August, from 158 EPA Water Quality Portal field readings (2010–2024). That is a typical value for the month, not a live reading.
When does Wilmes Lake thaw?
- Wilmes Lake typically has ice-out around Mar 27.
Explore Wilmes Lake across LakeGrade
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High nutrients, frequent algae, reduced clarity
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Where this data comes from
56 measurements from 1 monitoring station, 2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA56 samples · 2024
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- Analysis of Chlorophyll in Periphyton and Plankton
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)
Ice data from Minnesota DNR Climate