What is the cleanest lake in Utah?

Flaming Gorge Reservoir Antelope Flat in Daggett County is the highest-rated lake in Utah with an EPA water quality grade of A and 25.3 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.

Cleanest Lakes in Utah

Flaming Gorge Reservoir Antelope Flat in Daggett County leads the rankings with a water quality grade of A and 25.3 ft of clarity. Below are the top 26 cleanest monitored lakes in Utah, ranked by EPA water quality score.

Ranked List

#	Lake	County	Grade	Clarity	Phosphorus	Algae
1	Flaming Gorge Reservoir Antelope Flat	Daggett	A	25.3 ft	6.5 µg/L	1 µg/L
2	Flaming Gorge Reservoir	Daggett	A	31.8 ft	6.8 µg/L	1 µg/L
3	Wide Hollow Reservoir	Garfield	A	13.8 ft	36.5 µg/L	3.4 µg/L
4	Starvation Reservoir	Duchesne	A	11.2 ft	10 µg/L	1.4 µg/L
5	Recapture Reservoir	San Juan	A	8.9 ft	15.1 µg/L	1.7 µg/L
6	Red Fleet Reservoir	Uintah	A	5.9 ft	20 µg/L	1.8 µg/L
7	Newton Reservoir	Cache	A	15.4 ft	26 µg/L	1.7 µg/L
8	Hyrum Reservoir	Cache	A	6.9 ft	17.9 µg/L	2.2 µg/L
9	Moon Lake	Duchesne	A	9.5 ft	11.2 µg/L	2.7 µg/L
10	Lake Powell Off Cha Canyon	San Juan	B	13.1 ft	9.4 µg/L	-
11	Lake Powell Goodhope Bay Midchannel	Garfield	B	6.1 ft	26 µg/L	-
12	Lake Powell Off Davis Gulch	Kane	B	15.4 ft	13.1 µg/L	-
13	Lake Powell Halls Xing	Kane	B	12.3 ft	15.9 µg/L	-
14	Jordanelle Reservoir	Wasatch	C	8.2 ft	20 µg/L	1.9 µg/L
15	Mona Reservoir	Juab	C	2 ft	53.5 µg/L	4.3 µg/L
16	Strawberry Reservoir Bryants Fk T	Wasatch	C	15.6 ft	20 µg/L	2 µg/L
17	Porcupine Reservoir	Cache	C	8.5 ft	13.3 µg/L	3.8 µg/L
18	Willard Bay Reservoir	Box Elder	C	2.3 ft	55 µg/L	7.9 µg/L
19	Gsl Farmington Bay Outflow Lake	Davis	D	1 ft	484.5 µg/L	27.8 µg/L
20	Lower Bowns Reservoir	Garfield	D	9.2 ft	34 µg/L	9 µg/L
21	Cutler Reservoir	Cache	D	1.2 ft	109 µg/L	17.4 µg/L
22	Mill Meadow Reservoir	Wayne	D	5.9 ft	66 µg/L	22.7 µg/L
23	Baker Dam Reservoir	Washington	D	3.6 ft	78 µg/L	29.5 µg/L
24	Matt Warner Reservoir E	Uintah	D	6.2 ft	72 µg/L	15.2 µg/L
25	Utah Lake Sp @ Marina	Utah	F	0.7 ft	132 µg/L	55.3 µg/L
26	Farmington Bay Lake	Davis	F	-	405 µg/L	106 µg/L

Ranked List

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