Minnetonka Lake
Minnetonka Lake in Hennepin County, Minnesota has a water quality grade of C (Fair). Water clarity: 10 ft visibility. Phosphorus: 28 µg/L. Chlorophyll-a (algae): 10.1 µg/L. Maximum depth: 113 ft. Surface area: 14205.54 acres.
- Clarity
- 10 ft
- Typical in July
- 79°F
- Max depth
- 113 ft
- Area
- 14,206 acres
- Type
- Mesotrophic
- Trend
- ↓ Declining
- Public access
- Yes
- Ice-out
- Apr 12
- Open water
- 240 days
Next lake in Hennepin County
Minnetonka Lake is a 14,206-acre mesotrophic lake in Hennepin County, Minnesota with a maximum depth of 113 feet (30-foot average). Water quality is graded C based on 2 sampling years through 2025. Overall water quality is declining over recent sampling years. The lake supports 18 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 3 public boat landings. Compared to the 80 other monitored lakes in Hennepin County, Minnetonka Lake ranks #7 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-26. Grade methodology: LakeGrade methodology.
Watch Minnetonka Lake water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Swimming Safety
Grade onlyModerate
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.
Generally safe for swimming, moderate water quality
Water Quality Grade: C (Fair)
Good clarity, visible to about 10 ft. Phosphorus level: 28 µg/L. Chlorophyll-a: 10.1 µg/L. Trophic State Index: 50.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10 ft | Not graded |
| Phosphorus | 28 µg/L | Fair |
| Chlorophyll-a (Algae) | 10.1 µg/L | Fair |
| Trophic State Index (TSI) | 50 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Minnetonka Lake
Compare lakeside cabins, hotels, and vacation rentals near Minnetonka 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.
Top-rated places to stay near Minnetonka 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 trip? Cabins and lodging at Minnetonka Lake → · more Minnesota lake trips
Water Temperature
Minnetonka Lake typically sits around 79°F at the surface in July. Summer average is about 79°F. Usually warmest in Jul (about 79°F) and coldest in May (about 64°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 8 field readings (2023–2023) via the EPA Water Quality Portal. See the full Minnetonka Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 113 ft |
| Average Depth | 30 ft |
| Surface Area | 14,206 acres |
| Shoreline Length | 133.3 mi |
| Littoral Zone | 41% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Lake Minnetonka, Spring Park BayPublic
- Caribbean MarinaSemi-private
- Tonka Bay MarinaSemi-private
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Minnetonka 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.
DNR Fisheries Survey Summary
15 surveys on file from MN DNR Fisheries. Most recent: 2022-06-06 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 60.91 | 0.17 lb |
| Bluntnose Minnow | 42.46 | — |
| Largemouth Bass | 13.45 | 0.95 lb |
| BKS | 11.66 | — |
| Yellow Perch | 8.80 | 0.13 lb |
| BCS | 8.34 | — |
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.
Bluegill
Largemouth Bass
Yellow Perch
From the 2022-06-06 survey
Introduction Lake Minnetonka is a 14,206-acre lake in Hennepin County, with a maximum depth of 113 feet and an average depth of 30 feet. The lake is comprised of many connected bays and has a complex shoreline. Multiple public and private boat launches are located around Minnetonka, and the lake is popular with both…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Minnetonka Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — MinnetonkaFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — MinnetonkaFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — MinnetonkaPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.067 m/yr | 6 |
| Phosphorus | ↓ Declining | +0.56 µg/L/yr | 6 |
| Chlorophyll-a | → Stable | +0.03 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (323 observations).
Estimated open water season: 240 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 1878-03-11 (1878) | 2018-05-05 (2018) |
| Ice-In | 1996-11-25 (1996) | 2002-01-02 (2002) |
Most recent ice-out: 2026-04-03
EPA Impairment Status
Minnetonka Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN27-0133-10 · Official waterbody report · Matched by proximity (1.46 km)
Regulated Pollution Sources Nearby
2 EPA-permitted facilities operate within about 5 miles of Minnetonka Lake under Clean Water Act (NPDES) discharge permits.
- Former Advance Machine CoSpring Park · 0.8 mi away · NPDES MN0066648
- Boomerang Laboratories LlcSpring Park · 1 mi away · NPDES MN0066508
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.
County Ranking
Ranked #7 of 81 lakes in Hennepin County
Nearby Lakes in Hennepin County
Frequently asked questions about Minnetonka Lake
What is the water quality grade for Minnetonka Lake?
- Minnetonka Lake in Hennepin County, Minnesota has a water quality grade of C (Fair). Water clarity: 10 ft visibility. Phosphorus: 28 µg/L. Chlorophyll-a (algae): 10.1 µg/L. Maximum depth: 113 ft. Surface area: 14205.54 acres.
Is Minnetonka Lake safe to swim in?
- Generally safe for swimming, moderate water quality. Minnetonka Lake has a water quality grade of C (Fair). Algae concentration (chlorophyll-a) is 10.1 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Minnetonka Lake?
- Minnetonka Lake typically sits around 79°F at the surface in July, from 8 EPA Water Quality Portal field readings (2023–2023). That is a typical value for the month, not a live reading.
How deep is Minnetonka Lake?
- Minnetonka Lake has a maximum depth of 113 feet and an average depth of 30 feet. The lake covers 14205.54 acres.
What fish are in Minnetonka Lake?
- Fish species found in Minnetonka Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, common carp, green sunfish, hybrid sunfish, largemouth bass, muskellunge, northern pike, pumpkinseed, rock bass, smallmouth bass, walleye, white sucker, yellow bullhead, yellow perch. Minnetonka Lake is located in Hennepin County, Minnesota.
When does Minnetonka Lake thaw?
- Minnetonka Lake typically has ice-out around Apr 12. Ice typically forms around Dec 8. The open water season is approximately 240 days.
Are there boat ramps on Minnetonka Lake?
- Minnetonka Lake has 3 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Lake Minnetonka, Spring Park Bay, Caribbean Marina, Tonka Bay Marina. Public access is listed as yes.
Explore Minnetonka Lake across LakeGrade
Depth, room, public access, and the state wake-sport rules
Fish species and top-graded lakes across Minnesota
Fish species and best lakes in Hennepin County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its grade
Lakes in the Crow River Watershed, ranked by water quality
Moderate nutrients, good water quality
Minnesota's cleanest and most-polluted lakes, ranked
More Minnesota Lake Rankings
State Parks Near Minnetonka Lake
Other Grade C Lakes in Minnesota
Mesotrophic Lakes in Minnesota
Compare Minnetonka Lake With Nearby Lakes
Carver County · Grade A
Hennepin County · Grade D
Hennepin County · Grade D
Hennepin County · Grade D
Hennepin County · Grade F
Hennepin County · Grade D
Where this data comes from
1,428 measurements from 24 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
MNPCA1,428 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (24)
- MNPCA-27-0133-05-207
- MNPCA-27-0133-02-311
- MNPCA-27-0133-13-302
- MNPCA-27-0133-14-110
- MNPCA-27-0133-05-208
- MNPCA-27-0133-03-201
- MNPCA-27-0133-01-102
- MNPCA-27-0133-09-201
- MNPCA-27-0133-05-203
- MNPCA-27-0133-09-204
- MNPCA-27-0133-15-106
- MNPCA-27-0133-10-102
- MNPCA-27-0133-10-101
- MNPCA-27-0133-05-112
- MNPCA-27-0133-12-101
- MNPCA-27-0133-05-113
- MNPCA-27-0133-02-126
- MNPCA-27-0133-06-201
- MNPCA-27-0133-14-103
- MNPCA-27-0133-02-205
- MNPCA-27-0133-02-402
- MNPCA-27-0133-02-201
- MNPCA-27-0133-05-115
- MNPCA-27-0133-11-101
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
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