Watkins Mill Lake
Clay County, Missouri100 acresView mapDirections
Missouri DNR publishes the water-quality measurements for Watkins Mill Lake. Here is what has been measured.
- Eutrophic
- 29 ft max depth
Watkins Mill Lake in Clay County, Missouri has water-quality measurements published by Missouri DNR, shown here as reported. Water clarity: 3.2 ft visibility. Phosphorus: 39.2 µg/L. Chlorophyll-a (algae): 17.7 µg/L. Surface area: 100 acres.
Watkins Mill Lake is a 100-acre productive, nutrient-rich eutrophic lake in Clay County, Missouri with an estimated average depth of about 29 feet. Overall water quality is declining over recent sampling years. Compared to the 4 other monitored lakes in Clay County, Watkins Mill Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Missouri DNR, last sampled 2024-08-07. Methodology: how these readings are compared.
Watkins Mill Lake covers about 100 acres in Clay County. For a place on the water, look through cabin and lake-house rentals near Watkins Mill Lake on Vrbo. For a hotel or motel room, Booking.com and Expedia both search around the lake.
Swimming conditions
Readings onlyBacteria tested: exceedances
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Based on E. coli testing, Watkins Mill Lake frequently exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 11.7% of 264 samples across 8 seasons.
This is a historical summary of past testing, not a current condition — bacteria levels change quickly, especially after rain. Always check Missouri’s current beach and health-department advisories before swimming.
Whether Watkins Mill Lake is safe to swim in today is a call for the Missouri Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Watkins Mill Lake
These are the measurements Missouri DNR publishes for Watkins Mill Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 3.2 ft of visibility. Phosphorus 39.2 µg/L. Chlorophyll-a 17.7 µg/L. TSI 59.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 3.2ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 39.2µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 17.7µg/L | Fair GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 59 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Watkins Mill Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Watkins Mill Lake typically sits around 79°F at the surface in September. Summer average is about 82°F. Usually warmest in Jul (about 84°F) and coldest in May (about 74°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (74°F) to its warmest (84°F).
Typical surface water temperature by month, from 63 field readings (2010–2024) via the EPA Water Quality Portal. See the full Watkins Mill Lake water temperature breakdown →
Lake Details
Max depth
~29 ft est.
Surface area
100 acres
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Missouri has not published bathymetry for Watkins Mill Lake.
Lake Size & Watershed
Watershed (drainage) area
4 sq mi
HydroLAKES / HydroSHEDS
Shoreline
2.3 mi
HydroLAKES / HydroSHEDS
Elevation
909 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Stays via Stay22
Stays near Watkins Mill Lake
Compare lakeside cabins, hotels, and vacation rentals near Watkins Mill Lake in Clay 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.
Top-rated places to stay near Watkins Mill Lake
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Fishing Watkins Mill Lake
Water Quality Trend: Worsening
Based on 5 years of monitoring (2020–2024).
Water clarity
Worsening4 years
Phosphorus
Worsening+1 µg/L/yr5 years
Chlorophyll-a
Improving-2.21 µg/L/yr5 years
Reservoir Info (USACE NID)
Watkins Mill Lake is a man-made reservoir impounded by the Watkins Mill State Park Dam (completed 1971), built primarily for recreation on the TR-WILLIAMS CREEK; earth-type dam, 55 ft tall and 1,600 ft long.
- Surface area
- 100 ac
- Normal storage
- 2,600 ac-ft
- Max storage
- 2,600 ac-ft
- Drainage area
- 2.95 sq mi
- Hazard class
- High
- Owner
- MO. DNR PARKS
All listed purposes: Recreation;Flood Risk Reduction.
Source: USACE National Inventory of Dams, NID ID MO10011 · Operator website · Matched by proximity (0.11 km)
Regulated Pollution Sources Nearby
9 EPA-permitted facilities operate within about 5 miles of Watkins Mill Lake under Clean Water Act (NPDES) discharge permits. 5 facilities have a reported Clean Water Act violation in the past three years.
- Shelton Estates WwtfExcelsior Springs · 2.2 mi away · NPDES MO0103276Recent violation
- Excelsior Estates WwtpLawson · 3.3 mi away · NPDES MO0108511Recent violation
- Indian Ridge Mobile Home Court WwtfExcelsior Springs · 3.9 mi away · NPDES MO0107492Recent violation
- Homestead Village WwtpExcelsior Springs · 4 mi away · NPDES MO0056545Recent violation
- Mawc, Lawson LagoonLawson · 4.5 mi away · NPDES MO0091031Recent violation
- Watkins Woolen Mill State Park & StateLawson · 0.2 mi away · NPDES MO0034959
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.
Nearby Lakes in Clay County
Frequently asked questions about Watkins Mill Lake
Where is Watkins Mill Lake?
- Watkins Mill Lake is a lake in Clay County, Missouri. Its water-quality measurements are published by Missouri DNR and shown on this page as reported.
What is the water quality of Watkins Mill Lake?
- Watkins Mill Lake in Clay County, Missouri has water-quality measurements published by Missouri DNR, shown here as reported. Water clarity: 3.2 ft visibility. Phosphorus: 39.2 µg/L. Chlorophyll-a (algae): 17.7 µg/L. Surface area: 100 acres.
Is Watkins Mill Lake safe to swim in?
- Based on E. coli testing, Watkins Mill Lake frequently exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 11.7% of 264 samples across 8 seasons. That is a historical summary of past bacteria testing, not a current reading and not a swimming clearance. Bacteria levels can spike quickly after heavy rain, so whether Watkins Mill Lake is safe to swim in today is a call for Missouri's water agency and the county health department; check their current beach advisories before you swim.
What is the water temperature of Watkins Mill Lake?
- Watkins Mill Lake typically sits around 79°F at the surface in September, from 63 EPA Water Quality Portal field readings (2010–2024). That is a typical value for the month, not a live reading.
How deep is Watkins Mill Lake?
- No published bathymetric survey covers Watkins Mill Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 29 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 100 acres.
Explore Watkins Mill Lake across LakeQuality
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Where this data comes from
83 measurements from 2 monitoring stations, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Univ. of Missouri, Columbia
UMC80 samples · 2020–2024 - Missouri Dept. of Natural Resources
MDNR3 samples · 2020
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)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)