Waukesha County Lake Quality

Wisconsin, 39 lakes, average grade B (Good)

There are 39 graded lakes in Waukesha County. The mix is varied enough that the county-level average tells you the broad strokes, not the choose-this-cabin specifics. With an average grade of B, Waukesha County sits comfortably above the Wisconsin median.

Many of the county's lakes are deep glacial basins — over 50 feet at their deepest point — which gives them thermal stratification and a buffer against summer warming. Okauchee Lake (grade A) is the cleanest in the county.

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Quick Answers for Waukesha County

Cleanest lakes in Waukesha County →Cleanest lakes in Wisconsin →Safest swimming lakes in Wisconsin →

Planning a trip? Check special fishing regulations for Okauchee Lake, whether the fish are safe to eat, and the best times to fish — or browse the full Wisconsin regulations index.

Fishing in Waukesha County

Waukesha County Fishing Guide

Fish species and best-graded lakes in Waukesha County

DNR Reports (3)

Wisconsin DNR Fisheries Survey resources for lakes in Waukesha County. browse all reports →

These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).

2024
Upper Genesee Lake fall shocking survey, 2024
Fisheries Survey · WI DNR · 2024 (PDF)
2023
Lake Keesus spring shocking survey, 2023
Spring Shocking Survey · WI DNR · 2023 (PDF)
2023
Middle Genesee Lake spring shocking survey, 2023
Spring Shocking Survey · WI DNR · 2023 (PDF)

All Lakes in Waukesha County

39 lakes · 29 graded, 10 not rated29 graded lakes · 10 not rated, hidden

Include not-rated lakes (10)

#	Lake	Grade	Clarity	Phosphorus	Algae	Trophic	Max Depth	Access
1	AOkauchee LakeWaukesha	A	11.5 ft	18 µg/L	3.9 µg/L	No recent samples	90 ft	✓ Public
2	BSilver LakeWaukesha	B	10 ft	11.8 µg/L	No recent samples	No recent samples	40 ft	✓ Public
3	BAshippun LakeWaukesha	B	10 ft	13 µg/L	No recent samples	No recent samples	35 ft	✓ Public
4	BOttawa LakeWaukesha	B	13 ft	14.6 µg/L	No recent samples	No recent samples	16 ft	✓ Public
5	BCrooked LakeWaukesha	B	8 ft	16.5 µg/L	No recent samples	No recent samples	16 ft	✓ Public
6	BNorth LakeWaukesha	B	8 ft	17.9 µg/L	No recent samples	No recent samples	78.4 ft	Not recorded
7	BPretty LakeWaukesha	B	12.2 ft	12.2 µg/L	No recent samples	No recent samples	31 ft	✓ Public
8	BPewaukee LakeWaukesha	B	7.5 ft	19.9 µg/L	No recent samples	No recent samples	45 ft	✓ Public
9	BHunters LakeWaukesha	B	9.5 ft	15.9 µg/L	No recent samples	No recent samples	36 ft	✓ Public
10	BLac la Belle LakeWaukesha	B	4.8 ft	14.7 µg/L	No recent samples	No recent samples	45 ft	✓ Public
11	BLake KeesusWaukesha	B	9.2 ft	15.8 µg/L	No recent samples	No recent samples	42 ft	✓ Public
12	BEagle Spring LakeWaukesha	B	4.5 ft	17.9 µg/L	No recent samples	No recent samples	8 ft	✓ Public
13	BOconomowoc LakeWaukesha	B	12.5 ft	11.9 µg/L	No recent samples	No recent samples	60 ft	Not recorded
14	BOconomowoc Lake SiteWaukesha	B	13 ft	13.8 µg/L	No recent samples	No recent samples	60 ft	Not recorded
15	BSchool Section LakeWaukesha	B	6.2 ft	26.2 µg/L	No recent samples	No recent samples	8 ft	✓ Public
16	BLower Nashotah LakeWaukesha	B	9 ft	11.3 µg/L	No recent samples	No recent samples	43 ft	✓ Public
17	BSpring LakeWaukesha	B	No recent samples	12.2 µg/L	No recent samples	No recent samples	22 ft	✓ Public
18	BLower Nemahbin LakeWaukesha	B	10.9 ft	10.9 µg/L	No recent samples	No recent samples	36 ft	✓ Public
19	BDenoon LakeWaukesha	B	9 ft	24.7 µg/L	No recent samples	No recent samples	55 ft	✓ Public
20	BPine LakeWaukesha	B	25 ft	12.2 µg/L	No recent samples	No recent samples	85 ft	✓ Public
21	BFowler LakeWaukesha	B	14.5 ft	15.5 µg/L	No recent samples	No recent samples	50 ft	✓ Public
22	BUpper Nemahbin LakeWaukesha	B	12 ft	13.7 µg/L	No recent samples	No recent samples	60 ft	✓ Public
23	BNagawicka LakeWaukesha	B	9.5 ft	13.5 µg/L	No recent samples	No recent samples	90 ft	✓ Public
24	BLower Phantom LakeWaukesha	B	6.7 ft	15.7 µg/L	No recent samples	No recent samples	12 ft	✓ Public
25	BGolden LakeWaukesha	B	12.8 ft	14.4 µg/L	No recent samples	No recent samples	44 ft	✓ Public
26	BOkauchee Lake Deep Hole UsgsWaukesha	B	7.5 ft	23.7 µg/L	No recent samples	No recent samples	90 ft	✓ Public
27	BOcauchee LakeWaukesha	B	6.6 ft	17.5 µg/L	No recent samples	No recent samples	90 ft	✓ Public
28	BOkauchee Lake SiteWaukesha	B	4.6 ft	16.2 µg/L	No recent samples	No recent samples	90 ft	✓ Public
29	DMuskego LakeWaukesha	D	No recent samples	59.4 µg/L	No recent samples	No recent samples	23 ft	✓ Public
	NRUpper Kelly LakeWaukesha	NR	2 ft	No recent samples	No recent samples	No recent samples	31 ft	✓ Public
	NRBeaver LakeWaukesha	NR	No recent samples	No recent samples	No recent samples	No recent samples	46 ft	✓ Public
	NRMoose LakeWaukesha	NR	16 ft	No recent samples	No recent samples	No recent samples	No recent samples	✓ Public
	NRLapham Peak PondWaukesha	NR	5 ft	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRUpper Nemahbin LakeWaukesha	NR	12 ft	No recent samples	No recent samples	No recent samples	60 ft	✓ Public
	NRLac la Belle LakeWaukesha	NR	5.5 ft	No recent samples	No recent samples	No recent samples	45 ft	✓ Public
	NRLittle Muskego LakeWaukesha	NR	15.5 ft	No recent samples	No recent samples	No recent samples	65 ft	✓ Public
	NRHenrietta LakeWaukesha	NR	No recent samples	No recent samples	No recent samples	No recent samples	7 ft	✓ Public
	NRNorth Lake West BasinWaukesha	NR	9.5 ft	No recent samples	No recent samples	No recent samples	78.4 ft	✓ Public
	NRLower Kelly LakeWaukesha	NR	No recent samples	156 µg/L	No recent samples	No recent samples	36 ft	✓ Public

NR = not rated: the monitoring record does not meet the evidence bar for a grade. That is EPA Integrated Reporting Category 3 (insufficient information), not a failing grade. How grading works.

Lake Match

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Other Counties in Wisconsin

Outagamie County

1 lake · Avg grade A

Washington County

15 lakes · Avg grade B

Kenosha County

12 lakes · Avg grade B

Marinette County

22 lakes · Avg grade B

Forest County

34 lakes · Avg grade B

Waushara County

32 lakes · Avg grade B

See how Waukesha County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 39 states and 2 Canadian provinces.

Source: EPA National Aquatic Resource Surveys, 2026.