What is the cleanest lake in Union County, Iowa?

Three Mile Lake in Union County has the cleanest nutrient and algae readings in Union County, Iowa, with 2.7 feet of measured water clarity.

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 Union County, Iowa

Three Mile Lake in Union County leads the rankings on measured clarity and nutrients and 2.7 ft of clarity. Below are the top 6 cleanest monitored lakes in Union County, Iowa, ranked on EPA nutrient and algae measurements.

Ranked List

#	Lake	County	Clarity	Phosphorus	Algae
1	Three Mile Lake	Union	2.7 ft	43 µg/L	28.4 µg/L
2	Twelve Mile Lake	Union	2.4 ft	79 µg/L	45 µg/L
3	Green Valley Lake	Union	1.5 ft	103 µg/L	61.7 µg/L
4	Summit Lake	Union	1.4 ft	121 µg/L	45.7 µg/L
5	Mckinley Lake	Union	1 ft	150 µg/L	69.3 µg/L
6	Thayer Lake	Union	3.5 ft	68 µg/L	34.3 µg/L

Ranked List

More Answers for Union County, Iowa