Lenexa Lake
Johnson County, Kansas33 acresView mapDirections
Nutrients and algae sit mid-range for this region.
- Eutrophic
- #3 of 13 in the county
Lenexa Lake in Johnson County, Kansas has a water quality grade of C (Fair). Phosphorus: 29 µg/L. Chlorophyll-a (algae): 16.2 µg/L. Surface area: 33 acres.
- Area
- 33 acres
- Type
- Eutrophic
- Phosphorus
- 29 µg/L
- Chlorophyll-a
- 16.2 µg/L
- Trend
- ↓ Declining
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Watch Lenexa Lake’s letter
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Lenexa Lake is a 33-acre productive, nutrient-rich eutrophic lake in Johnson County, Kansas. Water quality is graded C based on 2 sampling years through 2021. Overall water quality is declining over recent sampling years. Compared to the 12 other monitored lakes in Johnson County, Lenexa Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, KDHE, last sampled 2021-09-14. Grade methodology: LakeQuality methodology.
Swimming Safety
Grade onlyAlgae risk
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
The C is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Water Quality Grade: C (Fair)
No clarity data. Phosphorus 29 µg/L. Chlorophyll-a 16.2 µg/L. TSI 55. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 29 µg/L | Good |
| Chlorophyll-a (Algae) | 16.2 µg/L | Fair |
| Trophic State Index (TSI) | 55 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 33 acres |
No bathymetric survey has been published for Lenexa Lake, so its depth is not documented here.
Fishing Lenexa Lake
Water Quality Trend: ↓ Declining
Based on 8 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Phosphorus | ↓ Declining | +20.94 µg/L/yr | 8 |
| Chlorophyll-a | ↓ Declining | +0.91 µg/L/yr | 8 |
Reservoir Info (USACE NID)
Lenexa Lake is a man-made reservoir impounded by the Lake Lenexa (completed 2006), built primarily for recreation on the Coon Creek-Tr; earth-type dam, 46 ft tall and 740 ft long.
- Surface area
- 33 ac
- Normal storage
- 570 ac-ft
- Max storage
- 1,020 ac-ft
- Drainage area
- 2.19 sq mi
- Hazard class
- High
- Owner
- LENEXA, CITY OF
Source: USACE National Inventory of Dams, NID ID KS09270 · Operator website
County Ranking
Ranked #3 of 13 lakes in Johnson County
Nearby Lakes in Johnson County
Frequently asked questions about Lenexa Lake
Where is Lenexa Lake?
- Lenexa Lake is a lake in Johnson County, Kansas. LakeQuality grades it C for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Lenexa Lake?
- Lenexa Lake in Johnson County, Kansas has a water quality grade of C (Fair). Phosphorus: 29 µg/L. Chlorophyll-a (algae): 16.2 µg/L. Surface area: 33 acres.
Is Lenexa Lake safe to swim in?
- The C is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Explore Lenexa Lake across LakeQuality
More Kansas Lake Rankings
Other Grade C Lakes in Kansas
Eutrophic Lakes in Kansas
Where this data comes from
43 measurements from 1 monitoring station, 2012–2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- EPA R7
EPA_R7_WQX43 samples · 2012–2021
Analytical methods
- Nutrient Analysis
- Chlorophyll a
- Fluorometric Analysis of Chlorophyll a (originally 2334.22A)
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.