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LakeQuality
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Pleasant Lake

Walworth County, WisconsinOligotrophic

Pleasant Lake earns an A — water clarity, phosphorus, and chlorophyll-a all rate among the best monitored waters in Walworth County. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.

Trophically, Pleasant Lake reads as oligotrophic — nutrient-poor, clear, and ecologically more sensitive to disturbance than richer lakes. A maximum depth of 29 ft puts Pleasant Lake in the middle of Wisconsin's depth distribution. The lake's 145 acres and partial shoreline records put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Within Walworth County's 34 graded waters, Pleasant Lake sits at rank 2, near the top of the local distribution.

Zebra mussels have been documented at Pleasant Lake, which alters the filter-feeding balance and can paradoxically increase water clarity while disrupting the food web. The fishery includes walleye alongside the lake's other 4 documented species — a notable draw for Wisconsin anglers. A documented public access point at Pleasant 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, Wisconsin DNR Surface Water, last sampled 2025-08-05. Grade methodology: LakeGrade methodology.

Swimming Safety

Excellent for swimming, crystal clear water with minimal algae

Water Quality Grade: A, Excellent

Crystal clear, you can see 44.3 ft down. Phosphorus level: 15.1 µg/L. Trophic State Index: 33.

MetricValueGrade
Water Clarity (Secchi Depth)44.3 ftA
Phosphorus15.1 µg/LA
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)33Oligotrophic

Low nutrients, clear water, excellent for swimming

Lake Details

CharacteristicValue
Maximum Depth29 ft
Surface Area145 acres
Public AccessYes

Fish Species

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

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

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

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

Invasive Species

Banded Mystery SnailCurly-Leaf PondweedEurasian Water-MilfoilHybrid Eurasian / Northern Water-MilfoilZebra Mussel

Water Quality Trend: Declining

Based on 7 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-0.786 m/yr7
Phosphorus Stable+0.01 µg/L/yr6
See year-by-year chart →

Recreation & Access

1
Boat Landings
Yes
Public Access

Location

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County Ranking

Ranked #2 of 34 lakes in Walworth County

Nearby Lakes in Walworth County

WI DNR Lake Profile

Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 1986. 6 stations on file (most recent sample 2025).

Fish Species (DNR-rated)

Largemouth Bass(Abundant)Panfish(Present)Northern Pike(Present)Walleye(Present)

Data Sources

Water quality data from the EPA Water Quality Portal

Grading methodology based on Metropolitan Council standards

Fish and recreation data from Wisconsin DNR Lakes

Most recent sample: 2025-08-05

Monitoring stations: 1