Clear Lake
Clear Lake in Brown County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 0.8 ft visibility. Phosphorus: 196 µg/L. Chlorophyll-a (algae): 92.8 µg/L. Maximum depth: 8 ft. Surface area: 251.78 acres.
- Clarity
- 0.8 ft
- Typical in August
- 74°F
- Max depth
- 8 ft
- Area
- 252 acres
- Type
- Hypereutrophic
- Trend
- → Stable
- 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 Brown County
Clear Lake is a 252-acre highly nutrient-loaded hypereutrophic lake in Brown County, Minnesota with a maximum depth of 8 feet (5-foot average). Water quality is graded F based on 2 sampling years through 2023. Water clarity is improving over recent sampling years. The lake supports 12 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 3 other monitored lakes in Brown County, Clear Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2023-10-11. 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 0.8 ft of visibility. Phosphorus level: 196 µg/L. Chlorophyll-a: 92.8 µg/L. Trophic State Index: 78.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 0.8 ft | Not graded |
| Phosphorus | 196 µg/L | Poor |
| Chlorophyll-a (Algae) | 92.8 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 Brown 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 →
Water Temperature
Clear Lake typically sits around 74°F at the surface in August. Summer average is about 77°F. Usually warmest in Jun (about 78°F) and coldest in Oct (about 50°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 101 field readings (2010–2023) via the EPA Water Quality Portal. See the full Clear Lake water temperature breakdown →
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 (1,342,765 cells/mL) on July 18, 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 | 8 ft |
| Average Depth | 5 ft |
| Surface Area | 252 acres |
| Shoreline Length | 3 mi |
| Littoral Zone | 100% |
| 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
DNR Fisheries Survey Summary
13 surveys on file from MN DNR Fisheries. Most recent: 2025-03-17 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 111.75 | 0.18 lb |
| Black Bullhead | 94.63 | 0.33 lb |
| Black Crappie | 59.09 | 0.3 lb |
| Walleye | 24.63 | 1.02 lb |
| Common Carp | 16.75 | 2.64 lb |
| Yellow Perch | 12.66 | 0.17 lb |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
Length Distributions
Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.
Bluegill
Black Bullhead
Black Crappie
Walleye
From the 2025-03-17 survey
Clear is a small lake (251 acres) located south of New Ulm, in Brown County. A medium-sized county owned access, with a single cement boat ramp, is present on the southeast shore. A fishing pier is available at the Lost Dog and Fox Hunters County Park. Clear has three miles of shoreline and a maximum depth of eight…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Clear Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — ClearFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — ClearFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — ClearPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: → Stable
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.051 m/yr | 4 |
| Phosphorus | ↓ Declining | +12.2 µg/L/yr | 4 |
| Chlorophyll-a | → Stable | -1.25 µg/L/yr | 4 |
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 MN08-0011-00 · Official waterbody report
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Clear Lake under Clean Water Act (NPDES) discharge permits.
- August Schell Brewing CoNew Ulm · 4.5 mi away · NPDES MN0022284
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 #2 of 4 lakes in Brown County
Nearby Lakes With Higher Grades
Clear 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 Brown County
Frequently asked questions about Clear Lake
What is the water quality grade for Clear Lake?
- Clear Lake in Brown County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 0.8 ft visibility. Phosphorus: 196 µg/L. Chlorophyll-a (algae): 92.8 µg/L. Maximum depth: 8 ft. Surface area: 251.78 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 92.8 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Clear Lake?
- Clear Lake typically sits around 74°F at the surface in August, from 101 EPA Water Quality Portal field readings (2010–2023). That is a typical value for the month, not a live reading.
How deep is Clear Lake?
- Clear Lake has a maximum depth of 8 feet and an average depth of 5 feet. The lake covers 251.78 acres.
What fish are in Clear Lake?
- Fish species found in Clear Lake include black bullhead, black crappie, bluegill, common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, walleye, white sucker, yellow bullhead, yellow perch. Clear Lake is located in Brown 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 (1,342,765 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
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Species activity outlook by water temperature and season
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Very high nutrients, dense algae, poor clarity
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Where this data comes from
200 measurements from 1 monitoring station, 2020–2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA200 samples · 2020–2023
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Turbidity, Nephelometric 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
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory