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Clear Lake

Polk County, WisconsinOligotrophic

Clear Lake earns an A — water clarity, phosphorus, and chlorophyll-a all rate among the best monitored waters in Polk County. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

Trophically, Clear Lake reads as oligotrophic — nutrient-poor, clear, and ecologically more sensitive to disturbance than richer lakes. Clear Lake reaches 26 ft at its deepest point — typical for Wisconsin mid-sized lakes, with seasonal stratification but limited cold-water refuge. At 30 acres, Clear Lake sits below the Wisconsin median: a small water where shoreline activity has an outsized effect on water quality. Within Polk County's 74 graded waters, Clear Lake sits at rank 1, near the top of the local distribution.

An invasive species record — Chinese Mystery Snail — has been logged at Clear Lake; Wisconsin DNR maintains the official infested-waters list. The fishery includes walleye alongside the lake's other 4 documented species — a notable draw for Wisconsin anglers. A documented public access point at Clear 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 2020-09-09. Grade methodology: LakeGrade methodology.

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Swimming Safety

Excellent for swimming, crystal clear water with minimal algae

Water Quality Grade: A, Excellent

Crystal clear, you can see 15.5 ft down. Phosphorus level: 13.9 µg/L. Trophic State Index: 40.

MetricValueGrade
Water Clarity (Secchi Depth)15.5 ftA
Phosphorus13.9 µg/LA
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)40Oligotrophic

Low nutrients, clear water, excellent for swimming

Lake Details

CharacteristicValue
Maximum Depth26 ft
Surface Area30 acres
Public AccessYes

Fish Species

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

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

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

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

Invasive & Introduced Species

Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.

Chinese Mystery SnailCurly-Leaf Pondweed

Water Quality Trend: Declining

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

MetricTrendChange/YearYears
Water Clarity Declining-5.25 m/yr2
Phosphorus Declining+4.25 µg/L/yr2

Recreation & Access

1
Boat Landings
Yes
Public Access

Location

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County Ranking

Ranked #1 of 74 lakes in Polk County

Nearby Lakes in Polk County

WI DNR Lake Profile

Authoritative data from the Wisconsin DNR LakePages. 1 station on file (most recent sample 2020).

Fish Species (DNR-rated)

Panfish(Abundant)Largemouth Bass(Common)Northern Pike(Common)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

Public boat-access points from the USGS National Boat Ramps inventory

Most recent sample: 2020-09-09

Monitoring stations: 1

Where to stay near Clear Lake

Compare lakeside cabins, hotels, and vacation rentals near Clear Lake in Polk County, Wisconsin — live availability and prices for your trip.

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