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Pine Lake

Waukesha County, WisconsinOligotrophic

Pine Lake earns an A — water clarity, phosphorus, and chlorophyll-a all rate among the best monitored waters in Waukesha 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, Pine Lake reads as oligotrophic — nutrient-poor, clear, and ecologically more sensitive to disturbance than richer lakes. Pine Lake is unusually deep for Wisconsin at 85 ft, which buffers the lake against summer warming and helps the deep water stay oxygenated. The lake's 711 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. Pine Lake ranks 5 of 48 in Waukesha County, putting it in the upper tier of locally monitored lakes.

Zebra mussels have been documented at Pine Lake, which alters the filter-feeding balance and can paradoxically increase water clarity while disrupting the food web. Walleye are documented at Pine Lake, one of 5 fish species on record for the lake. Public access is available — the lake is on the Wisconsin DNR public-access list. 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, Wisconsin DNR Surface Water, last sampled 2025-08-26. 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 82 ft down. Phosphorus level: 11.9 µg/L. Trophic State Index: 27.

MetricValueGrade
Water Clarity (Secchi Depth)82 ftA
Phosphorus11.9 µg/LA
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)27Oligotrophic

Low nutrients, clear water, excellent for swimming

Lake Details

CharacteristicValue
Maximum Depth85 ft
Surface Area711 acres
Public AccessYes

Fish Species

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

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

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

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

Invasive Species

Curly-Leaf PondweedEurasian Water-MilfoilHybrid Eurasian / Northern Water-MilfoilZebra MusselStarry Stonewort

Water Quality Trend: Improving

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

MetricTrendChange/YearYears
Water Clarity Improving+1.839 m/yr7
Phosphorus Improving-1.19 µg/L/yr4
See year-by-year chart →

Recreation & Access

1
Boat Landings
Yes
Public Access

Location

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County Ranking

Ranked #5 of 48 lakes in Waukesha County

Nearby Lakes in Waukesha County

State Parks Near Pine Lake

WI DNR Lake Profile

Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 2008. 3 stations on file (most recent sample 2026).

DNR Assessment
Reported
Trophic State Index 33 (oligotrophic) · 5-year average

Fish Species (DNR-rated)

Largemouth Bass(Common)Smallmouth Bass(Common)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: 2025-08-26

Monitoring stations: 1