St Joe Lake
St Joe Lake in Carver County, Minnesota has a water quality grade of A (Excellent). Water clarity: 8.4 ft visibility. Phosphorus: 21 µg/L. Chlorophyll-a (algae): 5.9 µg/L. Maximum depth: 52 ft. Surface area: 19.55 acres.
- Clarity
- 8.4 ft
- Typical in August
- 78°F
- Max depth
- 52 ft
- Area
- 20 acres
- Type
- Mesotrophic
- Trend
- ↓ Declining
- Public access
- Yes
- Ice-out
- Apr 3
- Open water
- 241 days
Next lake in Carver County
St Joe Lake is a 20-acre mesotrophic lake in Carver County, Minnesota with a maximum depth of 52 feet. Water quality is graded A based on 2 sampling years through 2024. Overall water quality is declining over recent sampling years. The lake supports 10 documented fish species including black bullhead, bluegill, and bowfin (dogfish). Public access is available. Compared to the 37 other monitored lakes in Carver County, St Joe Lake ranks #6 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-10-21. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLimited 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.
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A (Excellent)
Moderate clarity, visible to about 8.4 ft. Phosphorus level: 21 µg/L. Chlorophyll-a: 5.9 µg/L. Trophic State Index: 48.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 8.4 ft | Not graded |
| Phosphorus | 21 µg/L | Good |
| Chlorophyll-a (Algae) | 5.9 µg/L | Good |
| Trophic State Index (TSI) | 48 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near St Joe Lake
Compare lakeside cabins, hotels, and vacation rentals near St Joe Lake in Carver 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.
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Water Temperature
St Joe Lake typically sits around 78°F at the surface in August. Summer average is about 71°F. Usually warmest in Aug (about 78°F) and coldest in Jan (about 36°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 205 field readings (2010–2024) via the EPA Water Quality Portal. See the full St Joe Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 52 ft |
| Surface Area | 20 acres |
| Shoreline Length | 0.9 mi |
| Littoral Zone | 33% |
| Public Access | Yes |
Fish Species
Click a species to see every graded lake where it is documented.
Fishing St Joe Lake
DNR Fisheries Survey Summary
3 surveys on file from MN DNR Fisheries. Most recent: 1994-06-21 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 62.81 | 0.13 lb |
| Black Bullhead | 26.02 | 0.21 lb |
| Green Sunfish | 6.78 | 0.09 lb |
| Hybrid Sunfish | 3.93 | 0.21 lb |
| Northern Pike | 3.92 | 0.82 lb |
| Pumpkinseed | 2.92 | 0.03 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.
Bluegill
Black Bullhead
Green Sunfish
Hybrid Sunfish
From the 1994-06-21 survey
St. Joe Lake currently has a fish population dominated by small black bullheads, northern pike and several species of panfish. Approximately 25 percent of individual bluegill and hybrid sunfish sampled were over 7.0 inches in length. Growth rate was found to be generally below average for all species present in the…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for St Joe Lake. 2 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — St. JoeFisheries Lake Survey · MN DNR LakeFinder
- —Public Water Access Sites — St. JoePublic 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 | ↓ Declining | -0.125 m/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (36 observations).
Estimated open water season: 241 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2024-03-03 (2024) | 2013-04-28 (2013) |
| Ice-In | 2019-11-12 (2019) | 2015-12-19 (2015) |
Most recent ice-out: 2026-03-30
EPA Impairment Status
St Joe Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN10-0009-00 · Official waterbody report · Matched by proximity (1.43 km)
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of St Joe Lake under Clean Water Act (NPDES) discharge permits.
- Excelsior WtpExcelsior · 0.7 mi away · NPDES MN0041769
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 #6 of 38 lakes in Carver County
Nearby Lakes in Carver County
Frequently asked questions about St Joe Lake
What is the water quality grade for St Joe Lake?
- St Joe Lake in Carver County, Minnesota has a water quality grade of A (Excellent). Water clarity: 8.4 ft visibility. Phosphorus: 21 µg/L. Chlorophyll-a (algae): 5.9 µg/L. Maximum depth: 52 ft. Surface area: 19.55 acres.
Is St Joe Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. St Joe Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 5.9 µg/L. Always check local health department advisories before swimming.
What is the water temperature of St Joe Lake?
- St Joe Lake typically sits around 78°F at the surface in August, from 205 EPA Water Quality Portal field readings (2010–2024). That is a typical value for the month, not a live reading.
How deep is St Joe Lake?
- St Joe Lake has a maximum depth of 52 feet. The lake covers 19.55 acres.
What fish are in St Joe Lake?
- Fish species found in St Joe Lake include black bullhead, bluegill, bowfin (dogfish), brown bullhead, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, yellow bullhead. St Joe Lake is located in Carver County, Minnesota.
When does St Joe Lake thaw?
- St Joe Lake typically has ice-out around Apr 3. Ice typically forms around Nov 30. The open water season is approximately 241 days.
Explore St Joe Lake across LakeGrade
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Where this data comes from
56 measurements from 1 monitoring station, 2023–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA56 samples · 2023–2024
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake details from Minnesota DNR LakeFinder
Ice data from Minnesota DNR Climate