Clear Lake
Clear Lake in Le Sueur County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 1.2 ft visibility. Phosphorus: 309.5 µg/L. Chlorophyll-a (algae): 71.6 µg/L. Maximum depth: 18 ft. Surface area: 279.43 acres.
- Clarity
- 1.2 ft
- Max depth
- 18 ft
- Area
- 279 acres
- Type
- Hypereutrophic
- Public access
- Yes
Grade F measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Clear Lake →
Next lake in Le Sueur County
Clear Lake is a 279-acre highly nutrient-loaded hypereutrophic lake in Le Sueur County, Minnesota with a maximum depth of 18 feet. Water quality is graded F based on 2 sampling years through 2025. The lake supports 11 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 12 other monitored lakes in Le Sueur County, Clear Lake ranks #7 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-25. 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)
Very murky, less than 1.2 ft of visibility. Phosphorus level: 309.5 µg/L. Chlorophyll-a: 71.6 µg/L. Trophic State Index: 78.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.2 ft | Not graded |
| Phosphorus | 309.5 µg/L | Poor |
| Chlorophyll-a (Algae) | 71.6 µg/L | Poor |
| Trophic State Index (TSI) | 78 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Where to stay near Clear Lake
Compare lakeside cabins, hotels, and vacation rentals near Clear Lake in Le Sueur 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 Clear Lake are listed below.
Top-rated places to stay near Clear 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 →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Clear Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was very high (1,870,682 cells/mL) on July 19, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 18 ft |
| Surface Area | 279 acres |
| Shoreline Length | 2.9 mi |
| Littoral Zone | 71% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Clear LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Clear Lake
EPA Impairment Status
Clear 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 MN40-0079-00 · Official waterbody report
County Ranking
Ranked #7 of 13 lakes in Le Sueur County
Nearby Lakes With Higher Grades
Clear 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 Le Sueur County
Frequently asked questions about Clear Lake
What is the water quality grade for Clear Lake?
- Clear Lake in Le Sueur County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 1.2 ft visibility. Phosphorus: 309.5 µg/L. Chlorophyll-a (algae): 71.6 µg/L. Maximum depth: 18 ft. Surface area: 279.43 acres.
Is Clear 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. Clear Lake has a water quality grade of F (Algae-prone). Algae concentration (chlorophyll-a) is 71.6 µg/L. Always check local health department advisories before swimming.
How deep is Clear Lake?
- Clear Lake has a maximum depth of 18 feet. The lake covers 279.43 acres.
What fish are in Clear Lake?
- Fish species found in Clear Lake include black bullhead, black crappie, bluegill, freshwater drum, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, walleye, white sucker, yellow perch. Clear Lake is located in Le Sueur County, Minnesota.
Does Clear Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Clear Lake (clouds, ice, or an off-season gap). The most recent reading was very high (1,870,682 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Clear Lake?
- Clear Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Clear Lake. Public access is listed as yes.
Explore Clear Lake across LakeGrade
Fish species and top-graded lakes across Minnesota
Fish species and best lakes in Le Sueur County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its grade
Lakes in the Minnesota River Watershed, ranked by water quality
Very high nutrients, dense algae, poor clarity
Minnesota's cleanest and most-polluted lakes, ranked
More Minnesota Lake Rankings
State Parks Near Clear Lake
Other Grade F Lakes in Minnesota
Hypereutrophic Lakes in Minnesota
Where this data comes from
15 measurements from 1 monitoring station, 2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA15 samples · 2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by 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
Named boat-access points from the USGS National Boat Ramps inventory