Crystal Lake
Dakota County, Minnesota293 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Crystal Lake. Here is what has been measured.
- Eutrophic
- Impaired · Mercury
- Eurasian watermilfoil
- 37 ft max depth
- Public access
Crystal Lake in Dakota County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 7 ft visibility. Phosphorus: 27 µg/L. Chlorophyll-a (algae): 14.4 µg/L. Maximum depth: 37 ft. Surface area: 293.24 acres.
Minnesota DNR's Targeted Survey on August 7, 2023 caught 0.22 walleye per trap net at Crystal Lake. DNR survey details →
Crystal Lake is a 293-acre productive, nutrient-rich eutrophic lake in Dakota County, Minnesota with a maximum depth of 37 feet (9-foot average). Water clarity is declining over recent sampling years. The lake supports 13 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 44 other monitored lakes in Dakota County, Crystal Lake ranks #12 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-04. Methodology: how these readings are compared.
What Crystal Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Fishing13 species recorded
- Ice seasonIce-out around Apr 5
- Deep water37 ft surveyed max depth
Swimming conditions
Readings onlyModerate algae
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. Crystal Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
Whether Crystal Lake is safe to swim in today is a call for the Minnesota Pollution Control Agency and the Minnesota DNR and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Crystal Lake
These are the measurements Minnesota PCA publishes for Crystal Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Moderate clarity, visible to about 7 ft. Phosphorus 27 µg/L. Chlorophyll-a 14.4 µg/L. TSI 53.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 7ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 27µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 14.4µg/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. | 53 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Crystal Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Crystal Lake typically sits around 58°F at the surface in October. Summer average is about 72°F. Usually warmest in Jul (about 75°F) and coldest in Feb (about 38°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (38°F) to its warmest (75°F).
Typical surface water temperature by month, from 225 field readings (2010–2025) via the EPA Water Quality Portal. See the full Crystal Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Crystal Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was moderate (50,119 cells/mL) on March 13, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Minnesota DNR's Targeted Survey on August 7, 2023 caught 0.22 walleye per trap net at Crystal Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Crystal Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
14 surveys on file from MN DNR Fisheries. Most recent: 2025-09-04 (Targeted Survey).
14 surveys on file · most recent 2025-09-04 (Targeted Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Bluegill | 81.39 | 2–7 in 2023-08-07 | 0.11 lb |
| Black Bullhead | 18.25 | 14 in 2023-08-07 | 0.54 lb |
| Largemouth Bass | 16.34 | 5–16 in 2023-08-07 | 0.88 lb |
| Hybrid Sunfish | 10.11 | 3–10 in 2023-08-07 | 0.18 lb |
| Green Sunfish | 9.15 | 4 in 2023-07-11 | 0.1 lb |
CPUE = catch per unit effort, fish caught per net per set in a standardised survey. It measures abundance, not size, and is not a weekly bite report.
Length Distributions
Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.
Bluegill
Black Bullhead
Largemouth Bass
Hybrid Sunfish
From the 2025-09-04 survey
Minnesota DNR Fisheries IBI program staff conducted an assessment of lakeshore habitat on Crystal Lake on September 4th, 2025, following the Score the Shore survey protocols. The assessment consisted of 49 survey sites evenly spaced 70 meters around the lake. Assessments were made in three habitat zones: Shoreline…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Crystal Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — CrystalFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — CrystalFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — CrystalPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
37 ft
Average depth
9 ft
Surface area
293 acres
Shoreline
6.1 mi
Littoral zone
71%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
5 sq mi
HydroLAKES / HydroSHEDS
Elevation
932 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Crystal LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Crystal Lake
Compare lakeside cabins, hotels, and vacation rentals near Crystal Lake in Dakota County, Minnesota — 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 Crystal Lake
Prices for Oct 9–11, 4 adults. Change dates on the map below.
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Fish Species
Click a species to see every lake where it is documented.
Fishing Crystal 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.
Water Quality Trend: Stable
Based on 6 years of monitoring (2020–2025).
Water clarity
Worsening6 years
Phosphorus
Improving-2 µg/L/yr3 years
Chlorophyll-a
Stable-0.15 µg/L/yr3 years
Ice season
Typical ice-out
Apr 5
Earliest Mar 2, 2024 · Latest Apr 30, 2018
Typical ice-in
Nov 27
Earliest Nov 4, 1991 · Latest Dec 20, 2001
Most recent ice-out
Mar 26
2025
84 observations · Minnesota PCA ice records
EPA Impairment Status
Crystal Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN19-0027-00 · Official waterbody report
Nearby Lakes in Dakota County
Frequently asked questions about Crystal Lake
Where is Crystal Lake?
- Crystal Lake is a lake in Dakota County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Crystal Lake?
- Crystal Lake in Dakota County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 7 ft visibility. Phosphorus: 27 µg/L. Chlorophyll-a (algae): 14.4 µg/L. Maximum depth: 37 ft. Surface area: 293.24 acres.
Is Crystal Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Crystal Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
What is the water temperature of Crystal Lake?
- Crystal Lake typically sits around 58°F at the surface in October, from 225 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
How deep is Crystal Lake?
- Crystal Lake has a maximum depth of 37 feet and an average depth of 9 feet. The lake covers 293.24 acres.
What fish are in Crystal Lake?
- Fish species found in Crystal Lake include black bullhead, black crappie, bluegill, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, tiger muskellunge, walleye, white sucker, yellow bullhead, yellow perch. Crystal Lake is located in Dakota County, Minnesota.
What did the DNR fisheries survey find at Crystal Lake?
- Minnesota DNR's Targeted Survey on August 7, 2023 caught 0.22 walleye per trap net at Crystal Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Crystal Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
When does Crystal Lake thaw?
- Crystal Lake typically has ice-out around Apr 5. Ice typically forms around Nov 27. The open water season is approximately 236 days.
Does Crystal Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Crystal Lake (clouds, ice, or an off-season gap). The most recent reading was moderate (50,119 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Crystal Lake?
- Crystal Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Crystal Lake. Public access is listed as yes.
Can I fish at Crystal Lake?
- Crystal Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Minnesota's fish and wildlife agency, so check its current regulations before you go.
Explore Crystal Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
Fish species and the cleanest lakes across Minnesota
Fish species and best lakes in Dakota County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its readings
Lakes in the Minnesota River Watershed, ranked by water quality
Minnesota's cleanest lakes, ranked on agency measurements
More lakes in Minnesota
State Parks Near Crystal Lake
Other Lakes in Minnesota
Eutrophic Lakes in Minnesota
Where this data comes from
320 measurements from 3 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA320 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- Phosphorus by Two Reagent Colorimetry
- Analysis of Chlorophyll in Periphyton and Plankton
- 10200 H ~ Chlorophyll a-b-c Determination
- Turbidity, Probe Method
Monitoring station identifiers (3)
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
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory
Ice data from Minnesota DNR Climate