Valley County Lake Quality

Idaho, 15 lakes, average grade B (Good)

Valley County's 15 graded lakes fall in the moderate-density bracket for {{stateName}}. The county-level average smooths over real differences — a single agricultural watershed near the southwest corner can pull the average down even if the rest of the county runs clean. The county-wide average lands at B — solid water quality with most lakes carrying clear summer transparency and low-to-moderate phosphorus.

Most of the county's monitored lakes are shallow — under 50 feet — which means wind keeps the water column mixed all summer and sediment-bound phosphorus releases back into the surface layer whenever the bottom is disturbed. Nla Lake (A) is the cleanest in the county.

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Quick Answers for Valley County

Cleanest lakes in Valley County →Cleanest lakes in Idaho →Safest swimming lakes in Idaho →

Planning a trip? Check special fishing regulations for Nla Lake — or check the official Idaho fishing regulations.

All Lakes in Valley County

Rank	Lake	Grade	Clarity	Phosphorus
1	Nla Lake	A	18.6 ft	10.2 µg/L
2	Nla Lake	A	-	18.2 µg/L
3	Deadwood Reservoir	A	17.2 ft	14 µg/L
4	Deadwood Res Off Face of Dam Lake	A	-	25 µg/L
5	Cascade Reservoir A Sugar Loaf Island	B	8.5 ft	28 µg/L
6	Cascade R W of Sugarloaf Island Lake	B	8.2 ft	28 µg/L
7	Cascade Reservoir	B	8.2 ft	31 µg/L
8	Cascade R Lake	C	9.2 ft	32 µg/L
9	Cascade Reservoir Inlet	C	7.3 ft	20 µg/L
10	Nla Lake	C	7.7 ft	34000 µg/L
11	Nla Lake	C	9 ft	43.9 µg/L
12	Cascade R Lake	C	5.7 ft	30 µg/L
13	Nla Lake	C	4.4 ft	75000 µg/L
14	Cas Reservoir Inlet Between Lf And	C	4.3 ft	40 µg/L