What is the cleanest lake in Oklahoma?

Lake Thunderbird in Cleveland County is the highest-rated lake in Oklahoma with an EPA water quality grade of D and 0.3 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.

Lakes With Algae Problems in Oklahoma

6 lakes in Oklahoma report elevated algae levels (chlorophyll-a above 20 µg/L). These lakes are most likely to develop blue-green algae blooms during warm, calm summer weather. Avoid swimming during visible blooms and rinse pets after contact.

Ranked List

#	Lake	County	Grade	Clarity	Phosphorus	Algae
1	Lake Texoma	Johnston	NR	0.3 ft	-	233 µg/L
2	Lake Thunderbird	Cleveland	D	1.7 ft	59 µg/L	28.7 µg/L
3	Thunderbird Lake Nature Center	Pottawatomie	NR	-	37.5 µg/L	28.5 µg/L
4	Coon Creek Lake	Kay	D	-	359 µg/L	24 µg/L
5	Lake Texoma	Marshall	D	1.7 ft	142 µg/L	23 µg/L
6	Thunderbird Lake Fisherman'S	Cleveland	D	-	31.5 µg/L	21.4 µg/L

Ranked List

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