Late afternoon sun over Slim Lake, scattering a bright path across wind-textured water

Johnson County Lake Quality

Kansas, 20 lakes, measured by KDHE

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. 13 of those lakes carry recent nutrient and algae readings. The county-level summary describes that subset, not every water body listed. Most monitored lakes in Johnson County are productive, shallow basins; each lake page shows its own phosphorus and chlorophyll-a readings beside the EPA condition class.

The county's lakes lean shallow, which makes the readings sensitive to wind, sediment-resuspension, and any nutrient inputs from the watershed. The cleanest measured lake is New Olathe Lake.

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Quick Answers for Johnson County

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

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

All Lakes in Johnson County

20 lakes · 13 ranked on readings, 7 without enough sampling13 lakes ranked on readings · 7 without enough sampling, hidden

Include not-rated lakes (7)

#	Lake	Clarity	Phosphorus	Algae	Trophic	Max Depth	Access
1	New Olathe LakeJohnson	3.4 ft	29 µg/L	10 µg/L	No recent samples	No recent samples	Not recorded
2	Olathe LakeJohnson	3 ft	50 µg/L	14.2 µg/L	No recent samples	No recent samples	Not recorded
3	Lenexa LakeJohnson	No recent samples	29 µg/L	16.2 µg/L	No recent samples	No recent samples	Not recorded
4	Stoll Park LakeJohnson	No recent samples	70 µg/L	22 µg/L	No recent samples	No recent samples	Not recorded
5	Gardner LakeJohnson	2.3 ft	37 µg/L	43.5 µg/L	No recent samples	No recent samples	Not recorded
6	Cedar LakeJohnson	1.6 ft	113 µg/L	39.5 µg/L	No recent samples	No recent samples	Not recorded
7	Kingston Lake ParkJohnson	No recent samples	129.9 µg/L	58.7 µg/L	No recent samples	No recent samples	Not recorded
8	Sar Ko Park LakeJohnson	No recent samples	86.5 µg/L	51.9 µg/L	No recent samples	No recent samples	Not recorded
9	Tomahawk Creek Park LakeJohnson	No recent samples	162.1 µg/L	45.9 µg/L	No recent samples	No recent samples	Not recorded
10	South LakeJohnson	No recent samples	177.2 µg/L	72 µg/L	No recent samples	No recent samples	Not recorded
11	Leawood Park LakeJohnson	No recent samples	532.8 µg/L	42.4 µg/L	No recent samples	No recent samples	Not recorded
12	Water Works Park LakeJohnson	No recent samples	101.7 µg/L	107 µg/L	No recent samples	No recent samples	Not recorded
13	Antioch Park LakeJohnson	No recent samples	347.1 µg/L	61.3 µg/L	No recent samples	No recent samples	Not recorded
	Shawnee Mission LakeJohnson	4.3 ft	20 µg/L	9.7 µg/L	No recent samples	No recent samples	Not recorded
	Lenexa City LakeJohnson	2.4 ft	71 µg/L	40 µg/L	No recent samples	No recent samples	Not recorded
	Summer Crest Park LakeJohnson	No recent samples	109.6 µg/L	93.5 µg/L	No recent samples	No recent samples	Not recorded
	Ernie Miller Park LakeJohnson	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	Heritage LakeJohnson	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	Spring Hill City LakeJohnson	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	Olathe LakeJohnson	No recent samples	No recent samples	No recent samples	No recent samples	14 ft	Not recorded

NR = no nutrient or algae reading on record. The measurements are published as the authority reports them. Where the data comes from.

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Source: the Kansas Department of Health and Environment. See data sources.