Bass Lake
Bass Lake in Otter Tail County, Minnesota has a water quality grade of C (Fair). Water clarity: 8.5 ft visibility. Phosphorus: 40 µg/L. Chlorophyll-a (algae): 12.9 µg/L. Maximum depth: 36 ft. Surface area: 310.92 acres.
- Clarity
- 8.5 ft
- Typical in August
- 77°F
- Max depth
- 36 ft
- Area
- 311 acres
- Type
- Eutrophic
- Trend
- → Stable
- Public access
- Yes
Next lake in Otter Tail County
Bass Lake is a 311-acre productive, nutrient-rich eutrophic lake in Otter Tail County, Minnesota with a maximum depth of 36 feet. Water quality is graded C based on 2 sampling years through 2025. Water clarity is improving over recent sampling years. The lake supports 7 documented fish species including black bullhead, bluegill, and brown bullhead. Public access is available with 3 public boat landings. Compared to the 65 other monitored lakes in Otter Tail County, Bass Lake ranks #55 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-14. Grade methodology: LakeGrade methodology.
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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)
Moderate clarity, visible to about 8.5 ft. Phosphorus level: 40 µg/L. Chlorophyll-a: 12.9 µg/L. Trophic State Index: 53.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 8.5 ft | Not graded |
| Phosphorus | 40 µg/L | Fair |
| Chlorophyll-a (Algae) | 12.9 µg/L | Fair |
| Trophic State Index (TSI) | 53 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Bass Lake
Compare lakeside cabins, hotels, and vacation rentals near Bass Lake in Otter Tail 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
Bass Lake typically sits around 77°F at the surface in August. Summer average is about 75°F. Usually warmest in Aug (about 77°F) and coldest in Sep (about 65°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 18 field readings (2011–2025) via the EPA Water Quality Portal.
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Bass Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was high (248,886 cells/mL) on November 8, 2025.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 36 ft |
| Surface Area | 311 acres |
| Shoreline Length | 5.6 mi |
| Littoral Zone | 44% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Bass LakePublic
- German LakePublic
- Norway LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Bass Lake
DNR Fisheries Survey Summary
5 surveys on file from MN DNR Fisheries. Most recent: 2021-06-07 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Black Bullhead | 135.23 | 0.78 lb |
| Largemouth Bass | 45.42 | 0.96 lb |
| Bluegill | 37.93 | 0.25 lb |
| Pumpkinseed | 19.70 | 0.11 lb |
| Northern Pike | 13.54 | 2.93 lb |
| Walleye | 11.23 | 2.59 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
Largemouth Bass
Bluegill
Pumpkinseed
From the 2021-06-07 survey
Bass lake is a 292-acre eutrophic (fertile) lake located in south-central Otter Tail County. The town of Underwood, MN abuts the southeast shoreline of the lake. The immediate watershed is composed primarily of agricultural land interspersed with hardwood woodlots. The maximum depth is 36 feet; however, 47% of the…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Bass Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — BassFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — BassFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — BassPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: → Stable
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +1.25 m/yr | 2 |
| Phosphorus | → Stable | +0.65 µg/L/yr | 5 |
| Chlorophyll-a | ↓ Declining | +1.63 µg/L/yr | 5 |
EPA Impairment Status
Bass 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 MN56-0569-02 · Official waterbody report · Matched by proximity (2.48 km)
County Ranking
Ranked #55 of 66 lakes in Otter Tail County
Nearby Lakes With Higher Grades
Bass Lake holds Grade C. 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 Otter Tail County
Frequently asked questions about Bass Lake
What is the water quality grade for Bass Lake?
- Bass Lake in Otter Tail County, Minnesota has a water quality grade of C (Fair). Water clarity: 8.5 ft visibility. Phosphorus: 40 µg/L. Chlorophyll-a (algae): 12.9 µg/L. Maximum depth: 36 ft. Surface area: 310.92 acres.
Is Bass Lake safe to swim in?
- Generally safe for swimming, moderate water quality. Bass Lake has a water quality grade of C (Fair). Algae concentration (chlorophyll-a) is 12.9 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Bass Lake?
- Bass Lake typically sits around 77°F at the surface in August, from 18 EPA Water Quality Portal field readings (2011–2025). That is a typical value for the month, not a live reading.
How deep is Bass Lake?
- Bass Lake has a maximum depth of 36 feet. The lake covers 310.92 acres.
What fish are in Bass Lake?
- Fish species found in Bass Lake include black bullhead, bluegill, brown bullhead, largemouth bass, northern pike, walleye, yellow bullhead. Bass Lake is located in Otter Tail County, Minnesota.
Does Bass Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Bass Lake (clouds, ice, or an off-season gap). The most recent reading was high (248,886 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Bass Lake?
- Bass Lake has 3 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Bass Lake, German Lake, Norway Lake. Public access is listed as yes.
Explore Bass Lake across LakeGrade
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Where this data comes from
58 measurements from 2 monitoring stations, 2021–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA58 samples · 2021–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (2)
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