Skip to main content
LakeQuality
B

Sweeney Lake

Hennepin County, MinnesotaMesotrophic

On the LakeGrade scale Sweeney Lake grades a B, with clarity at 6.9 ft and 23 µg/L of phosphorus placing it above the Minnesota median. With clarity and phosphorus scored, the sub-grades cluster within a letter of each other, pointing to stable conditions rather than one specific stressor.

A TSI near 49 places Sweeney Lake in the mesotrophic band — moderate productivity, with seasonal swings between clearer spring water and richer late-summer conditions. Sweeney Lake reaches 28 ft at its deepest point — typical for Minnesota mid-sized lakes, with seasonal stratification but limited cold-water refuge. At 68 acres, Sweeney Lake sits below the Minnesota median: a small water where shoreline activity has an outsized effect on water quality. Among the 95 graded lakes in Hennepin County, Sweeney Lake ranks 9 — in the top quartile locally.

No invasive species are currently listed at Sweeney Lake — the lake remains off the Minnesota infested-waters roster. Bass fishing is part of the appeal: the species list runs to 12, anchored by largemouth and/or smallmouth bass. The lake lacks a documented public access point, so visitor use is limited. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2023-09-06. Grade methodology: LakeGrade methodology.

Reviewed by LakeQuality Editorial Team · Updated

Track Sweeney Lake

Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.

Swimming Safety

Good for swimming, clear water with low algae levels

Water Quality Grade: B, Good

Moderate clarity, visible to about 6.9 ft. Phosphorus level: 23 µg/L. Trophic State Index: 49.

MetricValueGrade
Water Clarity (Secchi Depth)6.9 ftC
Phosphorus23 µg/LB
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)49Mesotrophic

Moderate nutrients, good water quality

Lake Details

CharacteristicValue
Maximum Depth28 ft
Surface Area67.64 acres
Shoreline Length2.1 mi
Littoral Zone50%
Public AccessNo

Fish Species

black bullhead,black crappie,bluegill,common carp,green sunfish,hybrid sunfish,largemouth bass,northern pike,pumpkinseed,white sucker,yellow bullhead,yellow perch

Click a species to see all Minnesota and Wisconsin lakes where it is found.

→ Best fishing times for Sweeney Lake (14-day solunar calendar)

→ Is it safe to eat fish from Sweeney Lake? (mercury & PFAS guide)

Sweeney Lake fishing regulations (limits, seasons, special rules)

Water Quality Trend: Improving

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

MetricTrendChange/YearYears
Water Clarity Improving+0.356 m/yr5
Phosphorus Improving-4.3 µg/L/yr4
See year-by-year chart →

Location

Loading map…

County Ranking

Ranked #9 of 95 lakes in Hennepin County

Nearby Lakes in Hennepin County

DNR Fisheries Survey Summary

2 surveys on file from MN DNR Fisheries. Most recent: 1991-07-01 (Standard Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
Bluegill60.350.11 lb
Black Crappie10.710.2 lb
Black Bullhead8.710.33 lb
GIS4.000.34 lb
Northern Pike3.283.17 lb
Common Carp2.485.07 lb

CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.

From the 1991-07-01 survey

THE PRESENT FISH POPULATION IS DOMINATED BY BLHS, SMALL CEN, CATOSTOMIDS AND CYPRINIDS. BLGS AND BLBS WERE SAMPLED WELL ABOVE MEDIAN LEVELS; BLG AVERAGED 12.06 FISH PER POUND AND HAVE A PSD=10.1. BLBS AVERAGED 8.5-8.9 INCHES TOTAL LENGTH AND 2.88 FISH PER POUND. CARP WERE SAMPLED SLIGHTLY ABOVE MEDIAN LEVELS FOR…

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 Sweeney Lake. 1 report on file.

EPA Impairment Status

Sweeney Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).

Causes of impairment

Salinity / chlorides

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

Source: EPA ATTAINS assessment unit MN27-0035-01 · Official waterbody report

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

Lake details from Minnesota DNR LakeFinder

Most recent sample: 2023-09-06

Monitoring stations: 1