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Cottage Lake

Becker County, MinnesotaMesotrophic

Cottage Lake earns an A — every scored parameter (clarity and phosphorus) rates among the best monitored waters in Becker County. clarity and phosphorus rate similarly, so there is no obvious single lever to pull on watershed management.

The lake sits in the mesotrophic zone — the band where most well-managed Minnesota lakes fall. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. The lake's surface area is not consistently recorded across state datasets — physical context remains partial. Cottage Lake ranks 27 of 93 in Becker County — solidly in the upper half of the local distribution.

Cottage Lake has no invasive species recorded in Minnesota state databases as of 2021, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Cottage Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. No formal public access is documented at Cottage Lake — most use is by shoreline residents and their guests. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2021-09-06. Grade methodology: LakeGrade methodology.

Reviewed by LakeQuality Editorial Team · Updated

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Swimming Safety

Excellent for swimming, crystal clear water with minimal algae

Water Quality Grade: A, Excellent

Good clarity, visible to about 12 ft. Phosphorus level: 11 µg/L. Trophic State Index: 40.

MetricValueGrade
Water Clarity (Secchi Depth)12 ftB
Phosphorus11 µg/LA
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)40Mesotrophic

Moderate nutrients, good water quality

Water Quality Trend: Stable

Based on 5 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Improving+0.098 m/yr5
Phosphorus Declining+1.1 µg/L/yr5
See year-by-year chart →

Location

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County Ranking

Ranked #27 of 93 lakes in Becker County

Nearby Lakes in Becker County

State Parks Near Cottage Lake

EPA Impairment Status

Cottage Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).

Causes of impairment

Mercury

Source: EPA ATTAINS assessment unit MN03-0475-00 · Official waterbody report · Matched by proximity (2 km)

Data Sources

Water quality data from the EPA Water Quality Portal

Impairment status from EPA ATTAINS 303(d) database

Grading methodology based on Metropolitan Council standards

Most recent sample: 2021-09-06

Monitoring stations: 1