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LakeQuality

Crystal Lake

D
Grade D — Nutrient-rich
Nutrient-rich · #12 of 21 lakes in the county · 6.8 ft clear · Eutrophic · 31 acres · from C
Limited DataEutrophic

Crystal Lake in Scott County, Minnesota has a water quality grade of D (Nutrient-rich). Water clarity: 6.8 ft visibility. Phosphorus: 51 µg/L. Chlorophyll-a (algae): 12.5 µg/L. Maximum depth: 26 ft. Surface area: 31.44 acres.

Clarity
6.8 ft
Typical in August
79°F
Max depth
26 ft
Area
31 acres
Type
Eutrophic
Trend
Declining
Public access
No

Grade D measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Crystal Lake

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CUpper Prior Lake5 ft clear · Scott CountyView →
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Crystal Lake is a 31-acre productive, nutrient-rich eutrophic lake in Scott County, Minnesota with a maximum depth of 26 feet. Water quality is graded D based on 2 sampling years through 2024. Overall water quality is declining over recent sampling years. The lake supports 7 documented fish species including black bullhead, black crappie, and bluegill. No public access — the lake is private or restricted. Compared to the 20 other monitored lakes in Scott County, Crystal Lake ranks #12 for water quality.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-10-18. Grade methodology: LakeGrade methodology.

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Swimming Safety

Grade only

Limited data

Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.

Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum

Compare the safest swimming lakes near Minneapolis

Get alerts for Crystal Lake

Water Quality Grade: D (Nutrient-rich)

Moderate clarity, visible to about 6.8 ft. Phosphorus level: 51 µg/L. Chlorophyll-a: 12.5 µg/L. Trophic State Index: 55.

MetricValueGrade
Water Clarity (Secchi Depth)6.8 ftNot graded
Phosphorus51 µg/LPoor
Chlorophyll-a (Algae)12.5 µg/LFair
Trophic State Index (TSI)55Eutrophic

High nutrients, frequent algae, reduced clarity

Where to stay near Crystal Lake

Compare lakeside cabins, hotels, and vacation rentals near Crystal Lake in Scott 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. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around Crystal Lake are listed below.

Top-rated places to stay near Crystal Lake

Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.

Planning a whole trip? See where to stay at Minnesota’s top lakes →

Water Temperature

Crystal Lake typically sits around 79°F at the surface in August. Summer average is about 78°F. Usually warmest in Aug (about 79°F) and coldest in Oct (about 61°F). These are typical values by month — not a live reading.

Jan
Feb
Mar
Apr
May
70°
Jun
76°
Jul
78°
Aug
79°
Sep
Oct
61°
Nov
Dec

Typical surface water temperature by month, from 15 field readings (20222024) via the EPA Water Quality Portal. See the full Crystal Lake water temperature breakdown →

Lake Details

CharacteristicValue
Maximum Depth26 ft
Surface Area31 acres
Shoreline Length1.3 mi
Littoral Zone91%
Public AccessNo

Lake Size & Watershed

Watershed (drainage) area
1 sq mi
Elevation
948 ft

Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).

Fish Species

Click a species to see every graded lake where it is documented.

Fishing Crystal Lake

DNR Fisheries Survey Summary

4 surveys on file from MN DNR Fisheries. Most recent: 2016-08-15 (Standard Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
Black Bullhead27.720.21 lb
Brown Bullhead16.480.19 lb
Bluegill13.950.13 lb
Black Crappie10.150.18 lb
Northern Pike5.671.92 lb
Largemouth Bass3.450.94 lb

CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.

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.

Black Bullhead

16 fish · 511 in · 2016-08-15
530567891011

Brown Bullhead

4 fish · 710 in · 2009-08-24
21078910

Bluegill

89 fish · 27 in · 2016-08-15
31160234567

Black Crappie

50 fish · 411 in · 2016-08-15
19100trophy 104567891011

From the 2016-08-15 survey

Crystal Lake is a 32-acre Class 36 lake located in the City of Prior Lake. The area around Crystal Lake is currently being redeveloped, changing from a primarily agricultural area to a residential area with a city park. The City of Prior Lake operates an aerator throughout the winter months to reduce the potentials or…

Source: MN DNR LakeFinder Fisheries Lake Survey

DNR Reports & Resources

Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Crystal Lake. 2 reports on file.

These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).

Based on 6 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-0.118 m/yr6
Phosphorus Declining+15.55 µg/L/yr5
Chlorophyll-a Declining+6.5 µg/L/yr5
See year-by-year chart →

EPA Impairment Status

Crystal Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).

Causes of impairment

MercuryNutrients (phosphorus, nitrogen)

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit MN70-0072-00 · Official waterbody report · Matched by proximity (1.54 km)

County Ranking

Ranked #12 of 21 lakes in Scott County

Nearby Lakes With Higher Grades

Crystal Lake holds Grade D. 3 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.

Nearby Lakes in Scott County

Frequently asked questions about Crystal Lake

What is the water quality grade for Crystal Lake?

Crystal Lake in Scott County, Minnesota has a water quality grade of D (Nutrient-rich). Water clarity: 6.8 ft visibility. Phosphorus: 51 µg/L. Chlorophyll-a (algae): 12.5 µg/L. Maximum depth: 26 ft. Surface area: 31.44 acres.

Is Crystal Lake safe to swim in?

Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum. Crystal Lake has a water quality grade of D (Nutrient-rich). Algae concentration (chlorophyll-a) is 12.5 µg/L. Always check local health department advisories before swimming.

What is the water temperature of Crystal Lake?

Crystal Lake typically sits around 79°F at the surface in August, from 15 EPA Water Quality Portal field readings (2022–2024). That is a typical value for the month, not a live reading.

How deep is Crystal Lake?

Crystal Lake has a maximum depth of 26 feet. The lake covers 31.44 acres.

What fish are in Crystal Lake?

Fish species found in Crystal Lake include black bullhead, black crappie, bluegill, hybrid sunfish, largemouth bass, northern pike, pumpkinseed. Crystal Lake is located in Scott County, Minnesota.

Where this data comes from

39 measurements from 1 monitoring station, 2022–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • Minnesota Pollution Control Agency - Ambient Surface WaterMNPCA39 samples · 2022–2024

Analytical methods

  • Field measurement/observation, generic method
  • Phosphorus by Colorimetry
  • Analysis of Chlorophyll in Periphyton and Plankton
Monitoring station identifiers (1)

Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated 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