Washington County Lake Quality

Minnesota, 76 lakes, average grade C (Fair)

Washington County in Minnesota carries 76 graded lakes — one of the lake-richer counties in our dataset. Coverage that dense usually reflects active lake-association sampling alongside state-agency monitoring. The county average is C — the middle of the rubric, with one or two lakes pulling the average up or down depending on year.

The county's lakes lean shallow, which makes the grades sensitive to wind, sediment-resuspension, and any nutrient inputs from the watershed. The cleanest lake on the books is Twin Lake (A); the most-stressed is Mud Lake (F).

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Quick Answers for Washington County

Cleanest lakes in Washington County →Cleanest lakes in Minnesota →Safest swimming lakes in Minnesota →

Planning a trip? Check special fishing regulations for Twin Lake — or browse the full Minnesota regulations index.

Fishing in Washington County

Washington County Fishing Guide

Fish species and best-graded lakes in Washington County

DNR Reports (40)

Minnesota DNR LakeFinder resources for lakes in Washington County. browse all reports →

These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).

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Fisheries Lake Survey — White Bear
Fisheries Lake Survey · MN DNR LakeFinder
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Fisheries Lake Survey — Big Marine
Fisheries Lake Survey · MN DNR LakeFinder
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Fisheries Lake Survey — Tanners
Fisheries Lake Survey · MN DNR LakeFinder
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Fisheries Lake Survey — Square
Fisheries Lake Survey · MN DNR LakeFinder
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Fisheries Lake Survey — Cloverdale
Fisheries Lake Survey · MN DNR LakeFinder
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Fisheries Lake Survey — Long
Fisheries Lake Survey · MN DNR LakeFinder
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Fisheries Lake Survey — Little Carnelian
Fisheries Lake Survey · MN DNR LakeFinder
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Fisheries Lake Survey — Lily
Fisheries Lake Survey · MN DNR LakeFinder
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Fisheries Lake Survey — St. Croix
Fisheries Lake Survey · MN DNR LakeFinder
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Fisheries Lake Survey — Jane
Fisheries Lake Survey · MN DNR LakeFinder
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Fisheries Lake Survey — Keewahtin
Fisheries Lake Survey · MN DNR LakeFinder
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Fisheries Lake Survey — Forest
Fisheries Lake Survey · MN DNR LakeFinder
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Fisheries Lake Survey — Elmo
Fisheries Lake Survey · MN DNR LakeFinder
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Fisheries Lake Survey — Clear
Fisheries Lake Survey · MN DNR LakeFinder
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Fisheries Lake Survey — Carver
Fisheries Lake Survey · MN DNR LakeFinder
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Fisheries Lake Survey — Bone
Fisheries Lake Survey · MN DNR LakeFinder
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Fisheries Lake Survey — Big Carnelian
Fisheries Lake Survey · MN DNR LakeFinder
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Fisheries Lake Survey — Battle Creek
Fisheries Lake Survey · MN DNR LakeFinder
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Fish Stocking History — Battle Creek
Fish Stocking History · MN DNR LakeFinder
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Public Water Access Sites — Battle Creek
Public Water Access Sites · MN DNR LakeFinder
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Fish Stocking History — Big Carnelian
Fish Stocking History · MN DNR LakeFinder
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Public Water Access Sites — Big Carnelian
Public Water Access Sites · MN DNR LakeFinder
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Public Water Access Sites — Big Marine (Main Lake)
Public Water Access Sites · MN DNR LakeFinder
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Fish Stocking History — Bone
Fish Stocking History · MN DNR LakeFinder
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Public Water Access Sites — Bone
Public Water Access Sites · MN DNR LakeFinder
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Fish Stocking History — Carver
Fish Stocking History · MN DNR LakeFinder
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Fish Stocking History — Clear
Fish Stocking History · MN DNR LakeFinder
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Public Water Access Sites — Clear
Public Water Access Sites · MN DNR LakeFinder
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Fish Stocking History — Elmo
Fish Stocking History · MN DNR LakeFinder
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Public Water Access Sites — Elmo
Public Water Access Sites · MN DNR LakeFinder
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Fish Stocking History — Forest
Fish Stocking History · MN DNR LakeFinder
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Public Water Access Sites — Forest
Public Water Access Sites · MN DNR LakeFinder
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Public Water Access Sites — Grey Cloud Slough
Public Water Access Sites · MN DNR LakeFinder
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Public Water Access Sites — Jane
Public Water Access Sites · MN DNR LakeFinder
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Fish Stocking History — St. Croix
Fish Stocking History · MN DNR LakeFinder
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Public Water Access Sites — Lily
Public Water Access Sites · MN DNR LakeFinder
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Public Water Access Sites — Oneka
Public Water Access Sites · MN DNR LakeFinder
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Public Water Access Sites — Square
Public Water Access Sites · MN DNR LakeFinder
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Fish Stocking History — Tanners
Fish Stocking History · MN DNR LakeFinder
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Public Water Access Sites — Tanners
Public Water Access Sites · MN DNR LakeFinder

All Lakes in Washington County

76 lakes · 70 graded, 6 not rated70 graded lakes · 6 not rated, hidden

Include not-rated lakes (6)

#	Lake	Grade	Clarity	Phosphorus	Algae	Trophic	Max Depth	Access
1	ATwin LakeWashington	A	13 ft	13 µg/L	2.8 µg/L	No recent samples	No recent samples	Carry-in
2	AClear LakeWashington	A	14 ft	16 µg/L	3.1 µg/L	No recent samples	27 ft	Carry-in
3	ASquare LakeWashington	A	17 ft	9 µg/L	2.9 µg/L	No recent samples	68 ft	✓ Public
4	ABig Marine LakeWashington	A	12 ft	13 µg/L	4.6 µg/L	No recent samples	No recent samples	✓ Public
5	AWhite Bear LakeWashington	A	14.4 ft	15 µg/L	2.7 µg/L	No recent samples	83 ft	✓ Public
6	AHalfbreed LakeWashington	A	5.2 ft	9.5 µg/L	2.3 µg/L	No recent samples	34 ft	✓ Public
7	ABig Carnelian LakeWashington	A	14.5 ft	12 µg/L	3.4 µg/L	No recent samples	66 ft	✓ Public
8	ALily LakeWashington	A	10.5 ft	17 µg/L	5.1 µg/L	No recent samples	51 ft	✓ Public
9	ALittle Carnelian LakeWashington	A	20 ft	9 µg/L	2.1 µg/L	No recent samples	68 ft	Carry-in
10	AElmo LakeWashington	A	11.1 ft	12.5 µg/L	1.6 µg/L	No recent samples	140 ft	✓ Public
11	AJane LakeWashington	A	13 ft	21 µg/L	3.8 µg/L	No recent samples	39 ft	✓ Public
12	AOlson LakeWashington	A	11.2 ft	15 µg/L	2.6 µg/L	No recent samples	15 ft	Carry-in
13	AWhite Rock LakeWashington	A	7.5 ft	19.5 µg/L	2 µg/L	No recent samples	No recent samples	Carry-in
14	AWood Pile LakeWashington	A	10 ft	20 µg/L	4.2 µg/L	No recent samples	No recent samples	Carry-in
15	ASunset LakeWashington	A	9.5 ft	16 µg/L	3.6 µg/L	No recent samples	17 ft	Carry-in
16	AMaster Man LakeWashington	A	4.5 ft	19 µg/L	4.3 µg/L	No recent samples	No recent samples	Carry-in
17	APine Tree LakeWashington	A	8.5 ft	17 µg/L	4.1 µg/L	No recent samples	No recent samples	Carry-in
18	AEast Boot LakeWashington	A	15 ft	16 µg/L	2 µg/L	No recent samples	27 ft	Carry-in
19	AEdith LakeWashington	A	8.2 ft	14 µg/L	3.5 µg/L	No recent samples	43 ft	Carry-in
20	AMays LakeWashington	A	11 ft	16 µg/L	4.1 µg/L	No recent samples	25 ft	Carry-in
21	AWest Boot LakeWashington	A	14 ft	14 µg/L	2.5 µg/L	No recent samples	34 ft	Carry-in
22	BPoolWashington	B	5.9 ft	31.1 µg/L	No recent samples	No recent samples	78 ft	Carry-in
23	BO'Connors LakeWashington	B	6.6 ft	32 µg/L	13.5 µg/L	No recent samples	No recent samples	Carry-in
24	CLong LakeWashington	C	8 ft	25 µg/L	5.6 µg/L	No recent samples	25 ft	Carry-in
25	CClear LakeWashington	C	6.2 ft	33 µg/L	6.9 µg/L	No recent samples	28 ft	✓ Public
26	CFish LakeWashington	C	5 ft	26 µg/L	3.6 µg/L	No recent samples	No recent samples	✓ Public
27	CBass LakeWashington	C	6.5 ft	26.5 µg/L	7.6 µg/L	No recent samples	No recent samples	Carry-in
28	CPool of Lake St CroixWashington	C	4.3 ft	39.2 µg/L	No recent samples	No recent samples	78 ft	✓ Public
29	CLost LakeWashington	C	6.3 ft	25 µg/L	4.5 µg/L	No recent samples	34 ft	Carry-in
30	CSouth Twin LakeWashington	C	5 ft	32 µg/L	9 µg/L	No recent samples	No recent samples	Carry-in
31	CSunfish LakeWashington	C	8.9 ft	25 µg/L	7.2 µg/L	No recent samples	No recent samples	Carry-in
32	CTanners LakeWashington	C	6.6 ft	30 µg/L	13.1 µg/L	No recent samples	46 ft	✓ Public
33	CHay LakeWashington	C	3.5 ft	30 µg/L	4.8 µg/L	No recent samples	No recent samples	Carry-in
34	CFriedrich PondWashington	C	2.3 ft	60.5 µg/L	3.9 µg/L	No recent samples	No recent samples	Carry-in
35	CPlaisted LakeWashington	C	7.3 ft	25 µg/L	3.1 µg/L	No recent samples	No recent samples	Carry-in
36	CNorth School Section LakeWashington	C	7.8 ft	25.5 µg/L	8 µg/L	No recent samples	No recent samples	Carry-in
37	CLynch LakeWashington	C	5.8 ft	33 µg/L	9.8 µg/L	No recent samples	No recent samples	Carry-in
38	CJellums LakeWashington	C	6 ft	27 µg/L	8.2 µg/L	No recent samples	No recent samples	✓ Public
39	CBenz LakeWashington	C	4.5 ft	26 µg/L	3.6 µg/L	No recent samples	No recent samples	Carry-in
40	CBeutel'S PondWashington	C	2.5 ft	36.5 µg/L	3.2 µg/L	No recent samples	No recent samples	Carry-in
41	CDemontreville LakeWashington	C	10.2 ft	25.5 µg/L	11 µg/L	No recent samples	24 ft	✓ Public
42	CPat LakeWashington	C	6.5 ft	39 µg/L	11 µg/L	No recent samples	No recent samples	Carry-in
43	DLong LakeWashington	D	2.8 ft	47.5 µg/L	25.3 µg/L	No recent samples	60 ft	✓ Public
44	DUnnamed LakeWashington	D	3 ft	77 µg/L	28.5 µg/L	No recent samples	60 ft	✓ Public
45	DFish LakeWashington	D	2 ft	98.5 µg/L	12.5 µg/L	No recent samples	No recent samples	Carry-in
46	DFish LakeWashington	D	6 ft	42 µg/L	12 µg/L	No recent samples	34 ft	Carry-in
47	DBattle Creek LakeWashington	D	7.2 ft	52 µg/L	9.7 µg/L	No recent samples	15.3 ft	✓ Public
48	DMcdonald LakeWashington	D	5 ft	83 µg/L	26 µg/L	No recent samples	28 ft	Carry-in
49	DShields LakeWashington	D	4.4 ft	100.5 µg/L	19 µg/L	No recent samples	27 ft	Carry-in
50	DForest LakeWashington	D	5.1 ft	28 µg/L	16.5 µg/L	No recent samples	37 ft	✓ Public
51	DCarver LakeWashington	D	7.4 ft	43 µg/L	12.2 µg/L	No recent samples	36 ft	Carry-in
52	DBone LakeWashington	D	5.5 ft	29 µg/L	18.5 µg/L	No recent samples	30 ft	✓ Public
53	DPowers LakeWashington	D	5.8 ft	187 µg/L	14.5 µg/L	No recent samples	41 ft	Carry-in
54	DMarkgrafs LakeWashington	D	4.8 ft	60 µg/L	15 µg/L	No recent samples	No recent samples	Carry-in
55	DEagle Point LakeWashington	D	2.5 ft	62 µg/L	19.6 µg/L	No recent samples	No recent samples	Carry-in
56	DMckusick LakeWashington	D	6 ft	41 µg/L	10.1 µg/L	No recent samples	No recent samples	✓ Public
57	DSunnybrook LakeWashington	D	4.5 ft	41.5 µg/L	18.5 µg/L	No recent samples	No recent samples	Carry-in
58	DCloverdale LakeWashington	D	5 ft	30 µg/L	16.5 µg/L	No recent samples	28 ft	Carry-in
59	FMud LakeWashington	F	1.2 ft	89 µg/L	87 µg/L	No recent samples	No recent samples	Carry-in
60	FHorseshoe LakeWashington	F	4.8 ft	40 µg/L	31 µg/L	No recent samples	11.3 ft	Carry-in
61	FColby LakeWashington	F	3.8 ft	61 µg/L	34.5 µg/L	No recent samples	11 ft	Carry-in
62	FSand LakeWashington	F	2.5 ft	53 µg/L	42.5 µg/L	No recent samples	18 ft	✓ Public
63	FGoose LakeWashington	F	1.5 ft	101.5 µg/L	63 µg/L	No recent samples	No recent samples	Carry-in
64	FGoose LakeWashington	F	3 ft	40 µg/L	40 µg/L	No recent samples	25 ft	✓ Public
65	FRose LakeWashington	F	1.8 ft	132.5 µg/L	74.5 µg/L	No recent samples	11.3 ft	Carry-in
66	FNielson LakeWashington	F	1.6 ft	92.5 µg/L	66.5 µg/L	No recent samples	No recent samples	Carry-in
67	FS School Section LakeWashington	F	4 ft	42.5 µg/L	42.5 µg/L	No recent samples	26 ft	Carry-in
68	FKlawitter PondWashington	F	1.9 ft	96 µg/L	38 µg/L	No recent samples	No recent samples	Carry-in
69	FWilmes LakeWashington	F	3.5 ft	66.5 µg/L	31 µg/L	No recent samples	No recent samples	Carry-in
70	FDowns LakeWashington	F	1.8 ft	159 µg/L	68.5 µg/L	No recent samples	No recent samples	Carry-in
	NRLegion PondWashington	NR	7 ft	No recent samples	No recent samples	No recent samples	No recent samples	Carry-in
	NRBig Carnelian LakeWashington	NR	15 ft	No recent samples	No recent samples	No recent samples	66 ft	✓ Public
	NROneka LakeWashington	NR	4.4 ft	No recent samples	No recent samples	No recent samples	No recent samples	✓ Public
	NRGrey Cloud Slough LakeWashington	NR	3.3 ft	No recent samples	No recent samples	No recent samples	No recent samples	✓ Public
	NRTerrapin LakeWashington	NR	9.7 ft	No recent samples	No recent samples	No recent samples	No recent samples	Carry-in
	NRKramer LakeWashington	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Carry-in

NR = not rated: the monitoring record does not meet the evidence bar for a grade. That is EPA Integrated Reporting Category 3 (insufficient information), not a failing grade. How grading works.

Lake Match

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Other Counties in Minnesota

Clay County

2 lakes · Avg grade A

Morrison County

16 lakes · Avg grade A

Hubbard County

76 lakes · Avg grade A

Cass County

130 lakes · Avg grade A

Cook County

139 lakes · Avg grade A

Crow Wing County

121 lakes · Avg grade A

See how Washington County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 39 states and 2 Canadian provinces.

Source: EPA National Aquatic Resource Surveys, 2026.