Sand Lake is a mesotrophic lake in Marshall County, Iowa. Water quality is graded B based on 2 sampling years through 2024. Overall water quality is declining over recent sampling years. Compared to the 1 other monitored lakes in Marshall County, Sand Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-09-11. Grade methodology: LakeGrade methodology.
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Swimming Safety
Good for swimming, clear water with low algae levels
Water Quality Grade: B, Good
Murky, only visible to about 6.4 ft. Chlorophyll-a: 3.6 µg/L. Trophic State Index: 47.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 6.4 ft | D |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 3.6 µg/L | A |
| Trophic State Index (TSI) | 47 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Sand Lake
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Fishing Sand Lake
Water Quality Trend: ↓ Declining
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -1.35 m/yr | 2 |
| Chlorophyll-a | ↓ Declining | +6.8 µg/L/yr | 2 |
Location
County Ranking
Ranked #1 of 2 lakes in Marshall County
Nearby Lakes in Marshall County
Explore Sand Lake across LakeGrade
More Iowa Lake Rankings
Other Grade B Lakes in Iowa
Mesotrophic Lakes in Iowa
More records, surveys & data sources
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Regulated Pollution Sources Nearby
10 EPA-permitted facilities operate within about 5 miles of Sand 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.
- Marshalltown City Of Water Pollution ControlMarshalltown · 2 mi away · NPDES IA0038610MajorRecent violation
- Bruin Manufacturing Co., Inc.Marshalltown · 2.1 mi away · NPDES IA0081434Recent violation
- Ipl - Sutherland StationMarshalltown · 0.8 mi away · NPDES IA0000108
- Ipl - Precision Pipeline, LlcCedar Rapids · 1.5 mi away · NPDES IA0052365
- Marshalltown, City Of MS4Marshalltown · 2 mi away · NPDES IA0080039
- Fisher Controls International Llc (Main Office)Marshalltown · 2.1 mi away · NPDES IA0000230
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grading methodology based on Metropolitan Council standards
Most recent sample: 2024-09-11
Monitoring stations: 1