Johnson County Lake Quality

Kansas, 19 lakes, average grade D (Poor)

Johnson County's 19 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. On average, Johnson County lakes grade D, with phosphorus loading and reduced clarity showing up across most of the dataset.

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 (B) is the cleanest in the county.

Loading map…

Quick Answers for Johnson County

Cleanest lakes in Johnson County →Cleanest lakes in Kansas →Safest swimming lakes in Kansas →

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

All Lakes in Johnson County

Rank	Lake	Grade	Clarity	Phosphorus
1	Nla Lake	B	3.4 ft	22.7 µg/L
2	New Olathe Lake	C	3.4 ft	29 µg/L
3	Shawnee Mission Lake	C	4.3 ft	-
4	Lenexa Lake	C	-	29 µg/L
5	Ernie Miller Park Lake	C	-	55.6 µg/L
6	Olathe Lake	C	3.3 ft	80 µg/L
7	Gardner Lake	C	2.3 ft	17 µg/L
8	Nla Lake	D	3.1 ft	45000 µg/L
9	Stoll Park Lake	D	-	65.1 µg/L
10	Lenexa City Lake	D	2.4 ft	71 µg/L
11	Sar Ko Park Lake	D	-	92.5 µg/L
12	Leawood Park Lake	D	-	545.4 µg/L
13	Cedar Lake	F	1.6 ft	116.5 µg/L
14	Kingston Lake Park	F	-	140.2 µg/L
15	Tomahawk Creek Park Lake	F	-	162.1 µg/L
16	South Lake	F	-	181.9 µg/L
17	Water Works Park Lake	F	-	104.7 µg/L
18	Summer Crest Park Lake	F	-	109.6 µg/L
19	Antioch Park Lake	F	-	355.8 µg/L