Question 1

Cleanest Lakes in Washington County, Wisconsin?

Accepted Answer

Green Lake in Washington County leads the rankings with a water quality grade of A and 31.2 ft of clarity. Below are the top 13 cleanest monitored lakes in Washington County, Wisconsin, ranked by EPA water quality score.

Question 2

What is the cleanest lake in Washington County, Wisconsin?

Accepted Answer

Green Lake in Washington County is the highest-rated lake in Washington County, Wisconsin with an EPA water quality grade of A and 31.2 feet of water clarity.

Question 3

How are these rankings calculated?

Accepted Answer

Lakes are graded A through F using the Metropolitan Council methodology, which combines Secchi depth (water clarity), total phosphorus, and chlorophyll-a (algae) into a single score. Source data comes from the EPA Water Quality Portal.

#	Lake	County	Grade	Clarity	Phosphorus	Algae
1	Green Lake	Washington	A	31.2 ft	16.6 µg/L	-
2	Pike Lake	Washington	A	22.1 ft	19.3 µg/L	-
3	Lake Five	Washington	A	39.4 ft	14.7 µg/L	-
4	Big Cedar Lake	Washington	A	16.4 ft	14.1 µg/L	-
5	Little Cedar Lake	Washington	A	33.8 ft	12.1 µg/L	-
6	Big Cedar Lake-North Site-Near West Bend	Washington	A	12 ft	17.5 µg/L	-
7	Big Cedar Lake-South Site-Near West Bend	Washington	A	12.5 ft	15 µg/L	-
8	Little Friess Lake	Washington	A	26.2 ft	26.1 µg/L	-
9	Druid Lake	Washington	A	18 ft	23.7 µg/L	-
10	Big Cedar Lake	Washington	A	14.4 ft	15.5 µg/L	-
11	Bark Lake	Washington	B	18 ft	33 µg/L	-
12	Friess Lake	Washington	B	15.6 ft	33 µg/L	-
13	Big Cedar Lake Northern Basin Deep Site	Washington	B	8.7 ft	21 µg/L	-

Cleanest Lakes in Washington County, Wisconsin

Ranked List

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