Cottontail Lake
Jackson County, Missouri21 acresView mapDirections
Nutrients and algae run well above the regional average.
- Hypereutrophic
- Impaired · Mercury
- #9 of 23 in the county
- Limited data
Cottontail Lake in Jackson County, Missouri has a water quality grade of F (Algae-prone). Water clarity: 1.6 ft visibility. Phosphorus: 86.5 µg/L. Chlorophyll-a (algae): 39.4 µg/L. Surface area: 21 acres.
- Clarity
- 1.6 ft
- Area
- 21 acres
- Type
- Hypereutrophic
- Phosphorus
- 86.5 µg/L
- Chlorophyll-a
- 39.4 µg/L
- Trend
- ↓ Declining
Stays via Stay22
Stays near Cottontail Lake
Compare lakeside cabins, hotels, and vacation rentals near Cottontail Lake in Jackson County, Missouri — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around Cottontail Lake are listed below.
Top-rated places to stay near Cottontail Lake
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Watch Cottontail Lake’s letter
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Cottontail Lake is a 21-acre highly nutrient-loaded hypereutrophic lake in Jackson County, Missouri. Water quality is graded F based on 2 sampling years through 2023. Overall water quality is declining over recent sampling years. Compared to the 22 other monitored lakes in Jackson County, Cottontail Lake ranks #9 for water quality.
Source: EPA Water Quality Portal sampling records, Missouri DNR, last sampled 2023-10-03. Grade methodology: LakeQuality methodology.
Swimming Safety
Grade onlyLimited data
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 F is nutrients and algae, not a swimming clearance. Cottontail Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
Water Quality Grade: F (Algae-prone)
Very murky, less than 1.6 ft of visibility. Phosphorus 86.5 µg/L. Chlorophyll-a 39.4 µg/L. TSI 68. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.6 ft | Not graded |
| Phosphorus | 86.5 µg/L | Poor |
| Chlorophyll-a (Algae) | 39.4 µg/L | Poor |
| Trophic State Index (TSI) | 68 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 21 acres |
No bathymetric survey has been published for Cottontail Lake, so its depth is not documented here.
Fishing Cottontail Lake
Water Quality Trend: ↓ Declining
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.039 m/yr | 4 |
| Phosphorus | ↓ Declining | +12.62 µg/L/yr | 5 |
| Chlorophyll-a | ↓ Declining | +5.57 µg/L/yr | 5 |
Reservoir Info (USACE NID)
Cottontail Lake is a man-made reservoir impounded by the Cottontail Lake Dam (completed 1966), built primarily for recreation on the TR-EAST BR-BIG CREEK; earth-type dam, 25 ft tall.
- Surface area
- 21 ac
- Normal storage
- 154 ac-ft
- Max storage
- 281 ac-ft
- Drainage area
- 1,200 sq mi
- Hazard class
- Low
- Owner
- MO DEPT OF CONSERVATION
Source: USACE National Inventory of Dams, NID ID MO20025 · Operator website
EPA Impairment Status
Cottontail Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit MO_7379.00 · Official waterbody report
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Cottontail Lake under Clean Water Act (NPDES) discharge permits.
- Woodland Elementary School WwtpLee'S Summit · 0.8 mi away · NPDES MO0125351
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
County Ranking
Ranked #9 of 23 lakes in Jackson County
Nearby Lakes With Higher Grades
Cottontail Lake holds Grade F. 2 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
Nearby Lakes in Jackson County
Frequently asked questions about Cottontail Lake
Where is Cottontail Lake?
- Cottontail Lake is a lake in Jackson County, Missouri. LakeQuality grades it F for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Cottontail Lake?
- Cottontail Lake in Jackson County, Missouri has a water quality grade of F (Algae-prone). Water clarity: 1.6 ft visibility. Phosphorus: 86.5 µg/L. Chlorophyll-a (algae): 39.4 µg/L. Surface area: 21 acres.
Is Cottontail Lake safe to swim in?
- The F is nutrients and algae, not a swimming clearance. Cottontail Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
Explore Cottontail Lake across LakeQuality
Species activity outlook by water temperature and season
Where to stay at Missouri's top lakes, each with its grade
Very high nutrients, dense algae, poor clarity
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Other Grade F Lakes in Missouri
Hypereutrophic Lakes in Missouri
Where this data comes from
23 measurements from 2 monitoring stations, 2020–2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Univ. of Missouri, Columbia
UMC20 samples · 2020 - Missouri Dept. of Natural Resources
MDNR3 samples · 2023
Analytical methods
- Depth, Secchi disk in meters
- 4500 P E ~ Phosphorus in Water by Colorimetry- Ascorbic Acid Method
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- Nitrogen and Phosphorus, Total, Whole-water, Alkaline Persulfate Digest
Monitoring station identifiers (2)
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.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)