Wassermann Main Lake
Wassermann Main Lake in Carver County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 3 ft visibility. Phosphorus: 65.5 µg/L. Chlorophyll-a (algae): 39 µg/L. Maximum depth: 41 ft. Surface area: 169.68 acres.
- Clarity
- 3 ft
- Max depth
- 41 ft
- Area
- 170 acres
- Type
- Eutrophic
- Trend
- ↓ Declining
- Public access
- Yes
- Ice-out
- Mar 31
- Open water
- 246 days
Grade F measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Wassermann Main Lake →
Next lake in Carver County
Wassermann Main Lake is a 170-acre productive, nutrient-rich eutrophic lake in Carver County, Minnesota with a maximum depth of 41 feet (10-foot average). Water quality is graded F based on 2 sampling years through 2025. Overall water quality is declining over recent sampling years. The lake supports 13 documented fish species including black bullhead, black crappie, and bluegill. Public access is available. Compared to the 37 other monitored lakes in Carver County, Wassermann Main Lake ranks #37 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-13. 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 3 ft of visibility. Phosphorus level: 65.5 µg/L. Chlorophyll-a: 39 µg/L. Trophic State Index: 64.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3 ft | Not graded |
| Phosphorus | 65.5 µg/L | Poor |
| Chlorophyll-a (Algae) | 39 µg/L | Poor |
| Trophic State Index (TSI) | 64 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Wassermann Main Lake
Compare lakeside cabins, hotels, and vacation rentals near Wassermann Main Lake in Carver 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 Wassermann Main Lake are listed below.
Top-rated places to stay near Wassermann Main Lake
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 41 ft |
| Average Depth | 10 ft |
| Surface Area | 170 acres |
| Shoreline Length | 2.6 mi |
| Littoral Zone | 66% |
| Public Access | Yes |
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Wassermann Main 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.
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | -0.003 m/yr | 6 |
| Phosphorus | → Stable | -0.37 µg/L/yr | 6 |
| Chlorophyll-a | ↓ Declining | +1.48 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (33 observations).
Estimated open water season: 246 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2024-03-03 (2024) | 2001-04-15 (2001) |
| Ice-In | 2018-11-10 (2018) | 1999-12-21 (1999) |
Most recent ice-out: 2025-03-19
EPA Impairment Status
Wassermann Main 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 MN10-0048-00 · Official waterbody report · Matched by proximity (0.19 km)
County Ranking
Ranked #37 of 38 lakes in Carver County
Nearby Lakes With Higher Grades
Wassermann Main 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 Carver County
Frequently asked questions about Wassermann Main Lake
What is the water quality grade for Wassermann Main Lake?
- Wassermann Main Lake in Carver County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 3 ft visibility. Phosphorus: 65.5 µg/L. Chlorophyll-a (algae): 39 µg/L. Maximum depth: 41 ft. Surface area: 169.68 acres.
Is Wassermann Main 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. Wassermann Main Lake has a water quality grade of F (Algae-prone). Algae concentration (chlorophyll-a) is 39 µg/L. Always check local health department advisories before swimming.
How deep is Wassermann Main Lake?
- Wassermann Main Lake has a maximum depth of 41 feet and an average depth of 10 feet. The lake covers 169.68 acres.
What fish are in Wassermann Main Lake?
- Fish species found in Wassermann Main Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, yellow bullhead, yellow perch. Wassermann Main Lake is located in Carver County, Minnesota.
When does Wassermann Main Lake thaw?
- Wassermann Main Lake typically has ice-out around Mar 31. Ice typically forms around Dec 2. The open water season is approximately 246 days.
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Where this data comes from
267 measurements from 1 monitoring station, 2022–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA267 samples · 2022–2025
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Ice data from Minnesota DNR Climate