Cedar Lake is a 115-acre highly nutrient-loaded hypereutrophic lake in Linn County, Iowa. Water quality is graded F based on 2 sampling years through 2024. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 2 public boat landings. Compared to the 1 other monitored lakes in Linn County, Cedar Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-08-26. Grade methodology: LakeGrade methodology.
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Swimming Safety
Avoid swimming, very poor water quality, potential algae toxins
Water Quality Grade: F, Very Poor
Very murky, less than 0.9 ft of visibility. Chlorophyll-a: 129 µg/L. Trophic State Index: 79.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 0.9 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 129 µg/L | F |
| Trophic State Index (TSI) | 79 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 115 acres |
| Public Access | Yes |
Where to stay near Cedar Lake
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Fishing Cedar Lake
Water Quality Trend: ↓ Declining
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.041 m/yr | 4 |
| Chlorophyll-a | ↓ Declining | +6.68 µg/L/yr | 4 |
Recreation & Access
Location
County Ranking
Ranked #2 of 2 lakes in Linn County
Cleaner Lakes Within 30 Miles
Cedar Lake holds Grade F. 4 nearby lakes hold higher grades.
- CKent Park LakeJohnson County · 18.8 mi · Two grade letters higher (F → C)
- DPleasant Creek LakeLinn County · 11.9 mi · Higher grade (F → D)
- DLake MacbrideJohnson County · 14.4 mi · Higher grade (F → D)
- DCentral Park LakeJones County · 28.4 mi · Higher grade (F → D)
Nearby Lakes in Linn County
Explore Cedar Lake across LakeGrade
More Iowa Lake Rankings
Other Grade F Lakes in Iowa
Hypereutrophic Lakes in Iowa
More records, surveys & data sources
Reservoir Info (USACE NID)
Cedar Lake is a man-made reservoir impounded by the Cedar Lake Dam, built primarily for flood risk reduction on the Tr to Cedar River; earth-type dam, 15 ft tall and 2,000 ft long.
- Surface area
- 115 ac
- Normal storage
- 200 ac-ft
- Max storage
- 1,350 ac-ft
- Drainage area
- 4.7 sq mi
- Hazard class
- Low
- Owner
- City of Cedar Rapids
Source: USACE National Inventory of Dams, NID ID IA04469 · Operator website
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Regulated Pollution Sources Nearby
18 EPA-permitted facilities operate within about 5 miles of Cedar Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 3 facilities have a reported Clean Water Act violation in the past three years.
- Ipl - Prairie Creek Generating StationCedar Rapids · 3.5 mi away · NPDES IA0000540Major
- Cargill IncorporatedCedar Rapids · 1.9 mi away · NPDES IA0000647Recent violation
- Cedar Rapids Country ClubCedar Rapids · 2 mi away · NPDES IA0052651Recent violation
- Evergreen Packaging LlcCedar Rapids · 2.6 mi away · NPDES IA0003093Recent violation
- Ipl - Sixth Street Generating StationCedar Rapids · 0.5 mi away · NPDES IA0000132
- Quaker Manufacturing, LlcCedar Rapids · 0.7 mi away · NPDES IA0000761
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
Public boat-access points from the USGS National Boat Ramps inventory
Most recent sample: 2024-08-26
Monitoring stations: 1