What is the cleanest lake in St. Croix County, Wisconsin?

Bass Lake in St. Croix County is the highest-rated lake in St. Croix County, Wisconsin with an EPA water quality grade of B and 10 feet of water clarity.

How are these rankings calculated?

Lakes are graded A through F on nutrients and algae — total phosphorus, nitrogen, chlorophyll-a, and turbidity — against EPA National Lakes Assessment 2022 condition classes for that lake’s ecoregion. Water clarity (Secchi depth) is measured and shown; it is not the letter. Lakes without enough recent samples are UNRATED, not given an F. Source data comes from the EPA Water Quality Portal.

Cleanest Lakes in St. Croix County, Wisconsin

Bass Lake in St. Croix County leads the rankings with a water quality grade of B and 10 ft of clarity. Below are the top 18 cleanest monitored lakes in St. Croix County, Wisconsin, ranked by EPA water quality score.

Ranked List

#	Lake	County	Grade	Clarity	Phosphorus	Algae
1	Bass Lake	St. Croix	B	10 ft	14 µg/L	-
2	Apple Lake	St. Croix	D	2.5 ft	84.9 µg/L	-
3	Lake Mallalieu	St. Croix	D	2.8 ft	53.5 µg/L	-
4	Twin Lakes	St. Croix	NR	-	-	-
5	Lake George	St. Croix	NR	-	-	-
6	Glen Lake	St. Croix	NR	-	-	-
7	Pine Lake	St. Croix	NR	-	-	-
8	Casey Lake	St. Croix	NR	-	-	-
9	Brushy Mound Lake	St. Croix	NR	-	-	-
10	Three Lakes	St. Croix	NR	-	-	-
11	Hatfield Lake	St. Croix	NR	-	-	-
12	Oak Ridge Lake	St. Croix	NR	-	-	-
13	Riverdale Flowage	St. Croix	NR	-	-	-
14	Turtle Lake	St. Croix	NR	-	-	-
15	Pine Lake	St. Croix	NR	-	-	-
16	Little Falls Lake	St. Croix	NR	-	-	-
17	Perch Lake	St. Croix	NR	-	-	-
18	Dry Dam Lake	St. Croix	NR	-	-	-

Ranked List

More Answers for St. Croix County, Wisconsin