Mitchell Lake is a productive, nutrient-rich eutrophic lake in Black Hawk County, Iowa. Water quality is graded D based on 2 sampling years through 2024. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available with 2 public boat landings. Compared to the 6 other monitored lakes in Black Hawk County, Mitchell Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-10-23. Grade methodology: LakeGrade methodology.
Watch Mitchell Lake water quality
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Swimming Safety
Swimming not recommended, poor water quality with high algae risk
Water Quality Grade: D, Poor
Very murky, less than 2.3 ft of visibility. Chlorophyll-a: 18.7 µg/L. Trophic State Index: 62.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.3 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 18.7 µg/L | C |
| Trophic State Index (TSI) | 62 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Mitchell Lake
Compare lakeside cabins, hotels, and vacation rentals near Mitchell Lake in Black Hawk County, Iowa — 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.
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Fishing Mitchell Lake
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Source: USGS Nonindigenous Aquatic Species (NAS) Database. Hover a chip to see scientific name, ecological context, status, and first-observed year.
Water Quality Trend: ↑ Improving
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.085 m/yr | 5 |
| Chlorophyll-a | → Stable | +0.21 µg/L/yr | 5 |
Recreation & Access
Water Temperature
Mitchell Lake averages about 77°F at the surface in summer, usually warmest in Jul (about 81°F) and coldest in Sep (about 71°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 29 field readings (2010–2023) via the EPA Water Quality Portal. See the full Mitchell Lake water temperature breakdown →
Location & Depth Map
Free interactive depth-contour map of Mitchell Lake, reaching a maximum surveyed depth of 55 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Iowa DNR.
County Ranking
Ranked #1 of 7 lakes in Black Hawk County
Nearby Lakes in Black Hawk County
Explore Mitchell Lake across LakeGrade
More Iowa Lake Rankings
Other Grade D Lakes in Iowa
Eutrophic Lakes in Iowa
More records, surveys & data sources
EPA Impairment Status
Mitchell Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit IA 02-CED-463 · Official waterbody report · Matched by proximity (2.57 km)
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Regulated Pollution Sources Nearby
5 EPA-permitted facilities operate within about 5 miles of Mitchell Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 2 facilities have a reported Clean Water Act violation in the past three years.
- Waterloo City Of StpWaterloo · 0.5 mi away · NPDES IA0042650MajorRecent violation
- Covenant Medical CenterWaterloo · 1.9 mi away · NPDES IA0077437Recent violation
- Waterloo Residential Correction FacilityWaterloo · 1.7 mi away · NPDES IA0072290
- Waterloo, City Of MS4Waterloo · 1.9 mi away · NPDES IA0078301
- Flowers Baking Co. Of Waterloo, LlcWaterloo · 2 mi away · NPDES IA0062863
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.
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grading methodology based on Metropolitan Council standards
Public boat-access points from the USGS National Boat Ramps inventory
Most recent sample: 2024-10-23
Monitoring stations: 1