What is the cleanest lake in St. Clair County, Illinois?

Round Pond in St. Clair County has the cleanest nutrient and algae readings in St. Clair County, Illinois.

How are these rankings calculated?

Nutrients and algae, total phosphorus, nitrogen, chlorophyll-a and turbidity, are read against EPA National Lakes Assessment 2022 condition classes for that lake’s ecoregion. Water clarity (Secchi depth) is measured and shown separately. Lakes without enough recent samples are listed without a condition class rather than ranked low. Source data comes from the EPA Water Quality Portal.

Cleanest Lakes in St. Clair County, Illinois

Round Pond in St. Clair County leads the rankings on measured clarity and nutrients. Below are the top 6 cleanest monitored lakes in St. Clair County, Illinois, ranked on EPA nutrient and algae measurements.

Ranked List

#	Lake	County	Clarity	Phosphorus	Algae
1	Round Pond	St. Clair	-	-	-
2	Biebell Lake	St. Clair	-	-	-
3	River King Mine Lake	St. Clair	-	-	-
4	Spring Lake	St. Clair	-	-	-
5	Grand Marais Lake	St. Clair	-	-	-
6	Brush Lake	St. Clair	-	-	-

Ranked List

More Answers for St. Clair County, Illinois