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C

Tanners Lake

Washington County, MinnesotaEutrophic

Tanners Lake sits at a C on the grading scale — not impaired, not pristine, with summer measurements that vary year to year. The two scored sub-grades — clarity and phosphorus — track close together, so neither one is dragging the average down.

At a TSI of 52, Tanners Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. The lake bottoms out at 46 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. Tanners Lake is small — 74 acres alongside 1.7 miles of shoreline — which makes it sensitive to even modest changes in watershed runoff or recreational pressure. Tanners Lake ranks 24 of 31 in Washington County — at the lower end of the locally monitored distribution.

No invasive species are currently listed at Tanners Lake — the lake remains off the Minnesota infested-waters roster. Walleye are documented at Tanners Lake, one of 10 fish species on record for the lake. A documented public access point at Tanners Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. 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 2024-09-26. Grade methodology: LakeGrade methodology.

Reviewed by LakeQuality Editorial Team · Updated

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Swimming Safety

Generally safe for swimming, moderate water quality

Water Quality Grade: C, Fair

Murky, only visible to about 6.6 ft. Phosphorus level: 31 µg/L. Trophic State Index: 52.

MetricValueGrade
Water Clarity (Secchi Depth)6.6 ftD
Phosphorus31 µg/LC
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)52Eutrophic

High nutrients, frequent algae, reduced clarity

Lake Details

CharacteristicValue
Maximum Depth46 ft
Surface Area74.39 acres
Shoreline Length1.7 mi
Littoral Zone38%
Public AccessYes

Fish Species

black crappie,bluegill,green sunfish,hybrid sunfish,largemouth bass,northern pike,pumpkinseed,walleye,yellow bullhead,yellow perch

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

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

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

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

Water Quality Trend: Declining

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

MetricTrendChange/YearYears
Water Clarity Declining-0.05 m/yr5
Phosphorus Declining+4 µg/L/yr4
See year-by-year chart →

Location

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County Ranking

Ranked #24 of 31 lakes in Washington County

Cleaner Lakes Within 30 Miles

Tanners Lake holds Grade C. 5 nearby lakes hold higher grades.

See full comparison →

Nearby Lakes in Washington County

DNR Fisheries Survey Summary

11 surveys on file from MN DNR Fisheries. Most recent: 2011-08-01 (Standard Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
Bluegill32.640.13 lb
Yellow Perch9.370.11 lb
Black Bullhead4.900.73 lb
Hybrid Sunfish4.700.1 lb
Pumpkinseed4.190.09 lb
Black Crappie3.740.15 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

114 fish · 27 in · 2011-08-01
42210234567

Yellow Perch

12 fish · 57 in · 2011-08-01
840567

Black Bullhead

10 fish · 812 in · 2005-08-08
32089101112

Hybrid Sunfish

14 fish · 26 in · 2011-08-01
42023456

From the 2011-08-01 survey

Bluegills are the most abundant species in Tanners Lake. The population is considered average when comparing similar lakes. The average size found was 5.26 inches. Only 27.8% of the bluegills sampled exceeded 6 inches in length. Black crappies were also sampled in average abundance. Their average size was 6.17 inches.…

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 Tanners Lake. 3 reports on file.

EPA Impairment Status

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

Causes of impairment

PFASSalinity / chlorides

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

Source: EPA ATTAINS assessment unit MN82-0115-00 · 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: 2024-09-26

Monitoring stations: 2