Cedar Lake
Linn County, Iowa115 acresView mapDirections
Iowa DNR publishes the water-quality measurements for Cedar Lake. Here is what has been measured.
- Hypereutrophic
- 39 ft max depth
- Public access
Cedar Lake in Linn County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 0.9 ft visibility. Phosphorus: 256.5 µg/L. Chlorophyll-a (algae): 125.4 µg/L. Surface area: 115 acres.
Cedar Lake is a 115-acre highly nutrient-loaded hypereutrophic lake in Linn County, Iowa with an estimated average depth of about 39 feet. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available. 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. Methodology: how these readings are compared.
Cedar Lake covers about 120 acres in Linn County. For a place on the water, look through cabin and lake-house rentals near Cedar Lake on Vrbo. For a hotel or motel room, Booking.com and Expedia both search around the lake.
Swimming conditions
Readings onlyAlgae risk
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.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Cedar Lake is safe to swim in today is a call for the Iowa Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Cedar Lake
These are the measurements Iowa DNR publishes for Cedar 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 0.9 ft of visibility. Phosphorus 256.5 µg/L. Chlorophyll-a 125.4 µg/L. TSI 80.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 0.9ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 257µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 125µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 80 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Cedar Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~39 ft est.
Surface area
115 acres
Public access
Yes
Listed by Iowa DNR
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Iowa has not published bathymetry for Cedar Lake.
Lake Size & Watershed
Watershed (drainage) area
9 sq mi
HydroLAKES / HydroSHEDS
Shoreline
1.7 mi
HydroLAKES / HydroSHEDS
Elevation
712 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 Cedar Lake
Compare lakeside cabins, hotels, and vacation rentals near Cedar Lake in Linn 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. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around Cedar Lake are listed below.
Top-rated places to stay near Cedar Lake
Prices for Oct 23–25, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
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Fishing Cedar Lake
Water Quality Trend: Worsening
Based on 4 years of monitoring (2021–2024).
Water clarity
Worsening4 years
Phosphorus
Worsening+47.9 µg/L/yr4 years
Chlorophyll-a
Worsening+6.68 µg/L/yr4 years
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
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.
Nearby Lakes in Linn County
Frequently asked questions about Cedar Lake
Where is Cedar Lake?
- Cedar Lake is a lake in Linn County, Iowa. Its water-quality measurements are published by Iowa DNR and shown on this page as reported.
What is the water quality of Cedar Lake?
- Cedar Lake in Linn County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 0.9 ft visibility. Phosphorus: 256.5 µg/L. Chlorophyll-a (algae): 125.4 µg/L. Surface area: 115 acres.
Is Cedar Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Cedar Lake?
- No published bathymetric survey covers Cedar Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 39 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 115 acres.
Can I fish at Cedar Lake?
- Public access to Cedar Lake is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by Iowa's fish and wildlife agency, so check its current regulations before you go.
Explore Cedar Lake across LakeQuality
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Where this data comes from
47 measurements from 1 monitoring station, 2021–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Iowa DNR Surface Water Monitoring Data
21IOWA_WQX47 samples · 2021–2024
Analytical methods
- Unknown
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- In-Vitro Determination of Chlorophyll
- ISU modification of APHA 2130-B
Monitoring station identifiers (1)
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)