Thole Lake
Thole Lake in Scott County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 2.8 ft visibility. Phosphorus: 76.5 µg/L. Chlorophyll-a (algae): 39 µg/L. Maximum depth: 12 ft. Surface area: 118.52 acres.
- Clarity
- 2.8 ft
- Typical in August
- 78°F
- Max depth
- 12 ft
- Area
- 119 acres
- Type
- Eutrophic
- Trend
- ↓ Declining
- Public access
- Yes
- Ice-out
- Mar 25
Grade F measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Thole Lake →
Next lake in Scott County
Thole Lake is a 119-acre productive, nutrient-rich eutrophic lake in Scott County, Minnesota with a maximum depth of 12 feet. Water quality is graded F based on 2 sampling years through 2025. Overall water quality is declining over recent sampling years. The lake supports 12 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 20 other monitored lakes in Scott County, Thole Lake ranks #20 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-10. Grade methodology: LakeGrade methodology.
Watch Thole Lake water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Swimming Safety
Grade onlyAlgae 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.
Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom
Water Quality Grade: F (Algae-prone)
Very murky, less than 2.8 ft of visibility. Phosphorus level: 76.5 µg/L. Chlorophyll-a: 39 µg/L. Trophic State Index: 65.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.8 ft | Not graded |
| Phosphorus | 76.5 µg/L | Poor |
| Chlorophyll-a (Algae) | 39 µg/L | Poor |
| Trophic State Index (TSI) | 65 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Thole Lake
Compare lakeside cabins, hotels, and vacation rentals near Thole 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 Thole Lake are listed below.
Top-rated places to stay near Thole 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
Thole Lake typically sits around 78°F at the surface in August. Summer average is about 76°F. Usually warmest in Jul (about 78°F) and coldest in Oct (about 56°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 72 field readings (2010–2025) via the EPA Water Quality Portal. See the full Thole Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 12 ft |
| Surface Area | 119 acres |
| Shoreline Length | 5.2 mi |
| Littoral Zone | 100% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Thole LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Thole 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: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.117 m/yr | 6 |
| Phosphorus | ↓ Declining | +42.5 µg/L/yr | 2 |
| Chlorophyll-a | ↓ Declining | +7.5 µg/L/yr | 2 |
Ice Season
Historical ice data from Minnesota DNR (4 observations).
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2016-03-12 (2016) | 2018-05-01 (2018) |
Most recent ice-out: 2021-03-24
EPA Impairment Status
Thole 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 MN70-0120-01 · Official waterbody report
County Ranking
Ranked #20 of 21 lakes in Scott County
Nearby Lakes With Higher Grades
Thole Lake holds Grade F. 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 Scott County
Frequently asked questions about Thole Lake
What is the water quality grade for Thole Lake?
- Thole Lake in Scott County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 2.8 ft visibility. Phosphorus: 76.5 µg/L. Chlorophyll-a (algae): 39 µg/L. Maximum depth: 12 ft. Surface area: 118.52 acres.
Is Thole Lake safe to swim in?
- Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom. Thole Lake has a water quality grade of F (Algae-prone). Algae concentration (chlorophyll-a) is 39 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Thole Lake?
- Thole Lake typically sits around 78°F at the surface in August, from 72 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
How deep is Thole Lake?
- Thole Lake has a maximum depth of 12 feet. The lake covers 118.52 acres.
What fish are in Thole Lake?
- Fish species found in Thole Lake include black bullhead, black crappie, bluegill, brown bullhead, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, white sucker, yellow perch. Thole Lake is located in Scott County, Minnesota.
When does Thole Lake thaw?
- Thole Lake typically has ice-out around Mar 25.
Are there boat ramps on Thole Lake?
- Thole Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Thole Lake. Public access is listed as yes.
Explore Thole Lake across LakeGrade
Fish species and top-graded lakes across Minnesota
Fish species and best lakes in Scott County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its grade
Lakes in the Minnesota River Watershed, ranked by water quality
High nutrients, frequent algae, reduced clarity
Minnesota's cleanest and most-polluted lakes, ranked
More Minnesota Lake Rankings
State Parks Near Thole Lake
Other Grade F Lakes in Minnesota
Eutrophic Lakes in Minnesota
Where this data comes from
46 measurements from 1 monitoring station, 2024–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA46 samples · 2024–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- Total Phosphorus After Block Digestion
- 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
Ice data from Minnesota DNR Climate