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LakeQuality

Red Rock Lake

D
Grade D — Nutrient-rich
Nutrient-rich · #37 of 81 lakes in the county · 2.6 ft clear · Eutrophic · 97 acres
Eutrophic

Red Rock Lake in Hennepin County, Minnesota has a water quality grade of D (Nutrient-rich). Water clarity: 2.6 ft visibility. Phosphorus: 75 µg/L. Chlorophyll-a (algae): 28.5 µg/L. Maximum depth: 16 ft. Surface area: 96.91 acres.

Clarity
2.6 ft
Typical in August
74°F
Max depth
16 ft
Area
97 acres
Type
Eutrophic
Trend
Improving
Public access
Yes

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

Next lake in Hennepin County

DMccoy Lake2.1 ft clear · Hennepin CountyView →
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Red Rock Lake is a 97-acre productive, nutrient-rich eutrophic lake in Hennepin County, Minnesota with a maximum depth of 16 feet. Water quality is graded D based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. The lake supports 9 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 80 other monitored lakes in Hennepin County, Red Rock Lake ranks #37 for water quality.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-20. Grade methodology: LakeGrade methodology.

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Swimming Safety

Grade only

Algae risk

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 Red Rock Lake

Water Quality Grade: D (Nutrient-rich)

Very murky, less than 2.6 ft of visibility. Phosphorus level: 75 µg/L. Chlorophyll-a: 28.5 µg/L. Trophic State Index: 64.

MetricValueGrade
Water Clarity (Secchi Depth)2.6 ftNot graded
Phosphorus75 µg/LPoor
Chlorophyll-a (Algae)28.5 µg/LPoor
Trophic State Index (TSI)64Eutrophic

High nutrients, frequent algae, reduced clarity

Where to stay near Red Rock Lake

Compare lakeside cabins, hotels, and vacation rentals near Red Rock Lake in Hennepin 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 Red Rock Lake are listed below.

Top-rated places to stay near Red Rock 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

Red Rock Lake typically sits around 74°F at the surface in August. Summer average is about 73°F. Usually warmest in Jul (about 74°F) and coldest in Feb (about 37°F). These are typical values by month — not a live reading.

Jan
39°
Feb
37°
Mar
37°
Apr
50°
May
59°
Jun
72°
Jul
74°
Aug
74°
Sep
68°
Oct
55°
Nov
41°
Dec

Typical surface water temperature by month, from 432 field readings (20112025) via the EPA Water Quality Portal. See the full Red Rock Lake water temperature breakdown →

Lake Details

CharacteristicValue
Maximum Depth16 ft
Surface Area97 acres
Shoreline Length3.1 mi
Littoral Zone94%
Public AccessYes

Lake Size & Watershed

Watershed (drainage) area
3 sq mi
Elevation
833 ft

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

Recreation & Access

1
Boat Landings
Yes
Public Access
  • Red Rock LakePublic

Fish Species

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

Fishing Red Rock Lake

DNR Fisheries Survey Summary

7 surveys on file from MN DNR Fisheries. Most recent: 2021-06-07 (Standard Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
Black Bullhead48.120.54 lb
Bluegill34.250.19 lb
Yellow Perch33.510.22 lb
Largemouth Bass12.251.75 lb
Hybrid Sunfish9.580.23 lb
Northern Pike5.514.25 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

32 fish · 1012 in · 2021-06-07
23120101112

Bluegill

1,068 fish · 37 in · 2021-06-07
534267034567

Yellow Perch

1 fish · 66 in · 2021-06-07
106

Largemouth Bass

145 fish · 420 in · 2021-06-07
44220trophy 20468101214161820

From the 2021-06-07 survey

Red Rock Lake is a 97-acre lake with a maximum depth of 16 feet, located in Eden Prairie. A public boat access is located at a city park on the southeast side of the lake. A city ordinance restricts the size of motors in use on the lake to 10 horsepower. Red Rock Lake is managed for Bluegill, Black Crappie, and…

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 Red Rock Lake. 2 reports on file.

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

Based on 5 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Stable+0.009 m/yr5
Phosphorus Stable-0.17 µg/L/yr4
Chlorophyll-a Improving-3.73 µg/L/yr4
See year-by-year chart →

EPA Impairment Status

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

Causes of impairment

Mercury

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

Source: EPA ATTAINS assessment unit MN27-0076-00 · Official waterbody report

County Ranking

Ranked #37 of 81 lakes in Hennepin County

Nearby Lakes With Higher Grades

Red Rock 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.

See full comparison →

Nearby Lakes in Hennepin County

Frequently asked questions about Red Rock Lake

What is the water quality grade for Red Rock Lake?

Red Rock Lake in Hennepin County, Minnesota has a water quality grade of D (Nutrient-rich). Water clarity: 2.6 ft visibility. Phosphorus: 75 µg/L. Chlorophyll-a (algae): 28.5 µg/L. Maximum depth: 16 ft. Surface area: 96.91 acres.

Is Red Rock 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. Red Rock Lake has a water quality grade of D (Nutrient-rich). Algae concentration (chlorophyll-a) is 28.5 µg/L. Always check local health department advisories before swimming.

What is the water temperature of Red Rock Lake?

Red Rock Lake typically sits around 74°F at the surface in August, from 432 EPA Water Quality Portal field readings (2011–2025). That is a typical value for the month, not a live reading.

How deep is Red Rock Lake?

Red Rock Lake has a maximum depth of 16 feet. The lake covers 96.91 acres.

What fish are in Red Rock Lake?

Fish species found in Red Rock Lake include black bullhead, black crappie, bluegill, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, yellow bullhead, yellow perch. Red Rock Lake is located in Hennepin County, Minnesota.

Are there boat ramps on Red Rock Lake?

Red Rock Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Red Rock Lake. Public access is listed as yes.

Eutrophic Lakes in Minnesota

Where this data comes from

427 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • Minnesota Pollution Control Agency - Ambient Surface WaterMNPCA427 samples · 2020–2025

Analytical methods

  • Field measurement/observation, generic method
  • Phosphorus by Two Reagent Colorimetry
  • Analytical procedure not specified
  • Phosphorus by Colorimetry
  • 10200 H ~ Chlorophyll a-b-c Determination
  • 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

Named boat-access points from the USGS National Boat Ramps inventory