Hypereutrophic Lakes in Washington

30 hypereutrophic lakes in Washington. Very high nutrients, dense algae, poor clarity.

Hypereutrophic lakes (TSI above 70) are at the upper end of the productivity scale: visible algal blooms most weeks of summer, clarity often under 3 feet, and meaningful risk of harmful-algal-bloom toxin events. 30 hypereutrophic lakes are on the {{stateName}} books. Almost none of them are deep — 0% break 50 feet. Shallow basin plus heavy nutrient input is the consistent recipe.

Hypereutrophic lakes overwhelmingly grade D or F — the trophic class and the grade are measuring closely-related dimensions of the same underlying nutrient regime.

#	Lake	County	Grade	Clarity	Depth	TSI
1	Nla Lake	Okanogan	B	22.7 ft	-	73
2	Nla Lake	Grant	B	16.4 ft	-	76
3	Nla Lake	Okanogan	B	14.9 ft	-	79
4	Nla Lake	Stevens	B	18.7 ft	-	77
5	Nla Lake	Ferry	B	20.9 ft	-	76
6	Nla Lake	Pend Oreille	C	11.3 ft	-	77
7	Nla Lake	Pierce	C	10.9 ft	-	75
8	Nla Lake	King	C	12 ft	-	76
9	Nla Lake	Grant	C	12.1 ft	-	82
10	Nla Lake	Grant	C	11.6 ft	-	78
11	Nla Lake	Whatcom	C	10.2 ft	-	73
12	Nla Lake	Pend Oreille	C	14.7 ft	-	80
13	Nla Lake	Grays Harbor	C	10.6 ft	-	81
14	Nla Lake	Snohomish	C	13.8 ft	-	74
15	Nla Lake	Okanogan	C	14 ft	-	74
16	Nla Lake	King	C	7.7 ft	-	73
17	Nla Lake	Lewis	C	-	-	94
18	Nla Lake	Skamania	C	-	-	103
19	Nla Lake	Whatcom	C	-	-	84
20	Nla Lake	Mason	C	-	-	88
21	Nla Lake	San Juan	D	6.1 ft	-	88
22	Nla Lake	Thurston	D	7.7 ft	-	84
23	Nla Lake	Pacific	D	3.3 ft	-	83
24	Nla Lake	Stevens	D	7.7 ft	-	94
25	Nla Lake	Kittitas	D	3.1 ft	-	92
26	Nla Lake	Thurston	D	4.9 ft	-	91
27	Nla Lake	Grant	D	2.2 ft	-	98
28	Nla Lake	Lewis	F	6.3 ft	-	89
29	Nla Lake	Clark	F	3.3 ft	-	97
30	Nla Lake	Grant	F	1.1 ft	-	77

All hypereutrophic lakes →Minnesota version →Wisconsin version →Illinois version →Michigan version →Iowa version →Ohio version →Pennsylvania version →New York version →Missouri version →Indiana version →North Dakota version →South Dakota version →Florida version →Colorado version →North Carolina version →Vermont version →Texas version →Oregon version →Arkansas version →Oklahoma version →Kansas version →Nebraska version →Nevada version →Arizona version →Idaho version →Montana version →New Mexico version →Tennessee version →Alabama version →Virginia version →Kentucky version →Utah version →Wyoming version →All Washington lakes →

Source: EPA National Aquatic Resource Surveys, 2026.