Eutrophic Lakes in Washington

15 eutrophic lakes in Washington. High nutrients, frequent algae, reduced clarity.

Eutrophic lakes — TSI 50 to 70 — are nutrient-rich and productive, with persistent summer algal communities that drive visible reductions in clarity. These conditions are not failures; they reflect a lake doing what nutrient-loaded waters do. 15 {{stateName}} lakes register as eutrophic. Only 0% are deep — eutrophy correlates with shallowness, agricultural watersheds, and the kind of nutrient-input history that takes decades to shift.

Eutrophic lakes typically grade C or D on the LakeGrade rubric. The same nutrient richness that defines the trophic class drives the lower grade.

#	Lake	County	Grade	Clarity	Depth	TSI
1	Lake: Pattison Lake	Thurston	B	-	-	53
2	Lake: Barnes Lake	Thurston	B	-	-	53
3	Lake: Offutt Lake	Thurston	B	-	-	52
4	Ross Lake	Snohomish	C	-	-	59
5	Weallup Lake	Snohomish	C	-	-	57
6	Lacamas Lake	Clark	D	4.4 ft	-	56
7	Carp Lake	Pierce	D	6.6 ft	-	50
8	Waughop Lake	Pierce	D	5.6 ft	-	52
9	Lake Beecher	Snohomish	D	5.6 ft	-	52
10	Debra Jane Lake	Pierce	D	3.9 ft	-	57
11	Bonney Lake	Pierce	D	5.2 ft	-	53
12	Brook Lake	Grant	D	-	-	67
13	Jsl Lake	Snohomish	D	-	-	64
14	Vancouver Lake	Clark	D	1.2 ft	-	67
15	Lake	Thurston	F	-	-	70

All eutrophic 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 →Georgia version →Massachusetts version →All Washington lakes →

Source: EPA National Aquatic Resource Surveys, 2026.