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LakeQuality

Clear Lake

F
Grade F — Algae-prone
Algae-prone · #4 of 6 lakes in the county · 1.5 ft clear · Eutrophic · 434 acres · from D
Eutrophic

Clear Lake in Jackson County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 1.5 ft visibility. Phosphorus: 90.5 µg/L. Chlorophyll-a (algae): 44 µg/L. Maximum depth: 9 ft. Surface area: 434.16 acres.

Clarity
1.5 ft
Typical in August
77°F
Max depth
9 ft
Area
434 acres
Type
Eutrophic
Trend
Declining
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

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FLoon Lake0.9 ft clear · Jackson CountyView →
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Clear Lake is a 434-acre productive, nutrient-rich eutrophic lake in Jackson County, Minnesota with a maximum depth of 9 feet. Water quality is graded F based on 2 sampling years through 2023. Overall water quality is declining over recent sampling years. The lake supports 15 documented fish species including bigmouth buffalo, black bullhead, and black crappie. Public access is available with 2 public boat landings. Compared to the 5 other monitored lakes in Jackson County, Clear Lake ranks #4 for water quality.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2023-09-11. Grade methodology: LakeGrade methodology.

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Swimming Safety

Grade only

Algae 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

Compare the safest swimming lakes near Mankato

Get alerts for Clear Lake

Water Quality Grade: F (Algae-prone)

Very murky, less than 1.5 ft of visibility. Phosphorus level: 90.5 µg/L. Chlorophyll-a: 44 µg/L. Trophic State Index: 69.

MetricValueGrade
Water Clarity (Secchi Depth)1.5 ftNot graded
Phosphorus90.5 µg/LPoor
Chlorophyll-a (Algae)44 µg/LPoor
Trophic State Index (TSI)69Eutrophic

High nutrients, frequent algae, reduced clarity

Where to stay near Clear Lake

Compare lakeside cabins, hotels, and vacation rentals near Clear Lake in Jackson 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 77°F at the surface in August. Summer average is about 75°F. Usually warmest in Jul (about 78°F) and coldest in May (about 56°F). These are typical values by month — not a live reading.

Jan
Feb
Mar
Apr
May
56°
Jun
71°
Jul
78°
Aug
77°
Sep
71°
Oct
Nov
Dec

Typical surface water temperature by month, from 35 field readings (20102023) via the EPA Water Quality Portal. See the full Clear Lake water temperature breakdown →

Blue-Green Algae (Cyanobacteria)

No current satellite reading

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 high (990,832 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

CharacteristicValue
Maximum Depth9 ft
Surface Area434 acres
Shoreline Length3.8 mi
Littoral Zone100%
Public AccessYes

Lake Size & Watershed

Watershed (drainage) area
3 sq mi
Elevation
1,490 ft

Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).

Recreation & Access

2
Boat Landings
Yes
Public Access
  • Clear Lake (South)Public
  • Clear Lake (North)Public

Fish Species

Click a species to see every graded lake where it is documented.

Fishing Clear 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.

bighead carpsilver carp

DNR Fisheries Survey Summary

22 surveys on file from MN DNR Fisheries. Most recent: 2023-09-21 (Targeted Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
Black Bullhead62.130.65 lb
Walleye25.111.91 lb
Yellow Perch23.230.34 lb
Green Sunfish10.540.05 lb
YLB7.500.49 lb
Freshwater Drum4.701.53 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.

Black Bullhead

1 fish · 1111 in · 2023-06-05
1011

Walleye

35 fish · 69 in · 2023-09-21
281406789

Yellow Perch

31 fish · 712 in · 2019-06-03
1050trophy 12789101112

Green Sunfish

2 fish · 34 in · 1999-07-12
1034

From the 2023-09-21 survey

Clear Lake is a 415-acre, class 43 lake, located four miles west of the City of Jackson in Jackson County. The lake has a maximum depth of 9.0 feet and a shoreline length of 3.8 miles. Clear Lake has historically been a good Walleye fishery and therefore is managed primarily for Walleye. Secondary management species…

Source: MN DNR LakeFinder Fisheries Lake Survey

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).

Based on 2 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Improving+0.04 m/yr2
Phosphorus Declining+4 µg/L/yr2
Chlorophyll-a Declining+16.1 µg/L/yr2

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

Nutrients (phosphorus, nitrogen)

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit MN32-0022-00 · Official waterbody report

County Ranking

Ranked #4 of 6 lakes in Jackson 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.

See full comparison →

Nearby Lakes in Jackson County

Frequently asked questions about Clear Lake

What is the water quality grade for Clear Lake?

Clear Lake in Jackson County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 1.5 ft visibility. Phosphorus: 90.5 µg/L. Chlorophyll-a (algae): 44 µg/L. Maximum depth: 9 ft. Surface area: 434.16 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 44 µg/L. Always check local health department advisories before swimming.

What is the water temperature of Clear Lake?

Clear Lake typically sits around 77°F at the surface in August, from 35 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 9 feet. The lake covers 434.16 acres.

What fish are in Clear Lake?

Fish species found in Clear Lake include bigmouth buffalo, black bullhead, black crappie, bluegill, channel catfish, common carp, freshwater drum, green sunfish, largemouth bass, northern pike, smallmouth bass, walleye, yellow bass, yellow bullhead, yellow perch. Clear Lake is located in Jackson 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 high (990,832 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 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Clear Lake (South), Clear Lake (North). Public access is listed as yes.

State Parks Near Clear Lake

Where this data comes from

30 measurements from 1 monitoring station, 2022–2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • Minnesota Pollution Control Agency - Ambient Surface WaterMNPCA30 samples · 2022–2023

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