Bear Trap Lake
Bear Trap Lake in Polk County, Wisconsin has a water quality grade of C (Fair). Water clarity: 8.8 ft visibility. Phosphorus: 24.9 µg/L. Maximum depth: 25 ft. Surface area: 247 acres.
Wisconsin DNR lists Panfish as common on Bear Trap Lake. DNR survey details →
- Clarity
- 8.8 ft
- Typical in August
- 74°F
- Max depth
- 25 ft
- Area
- 247 acres
- Type
- Mesotrophic
- Trend
- ↑ Improving
- Public access
- Yes
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Bear Trap Lake is a 247-acre mesotrophic lake in Polk County, Wisconsin with a maximum depth of 25 feet. Water quality is graded C based on 1 sampling years through 2026. Overall water quality is improving over recent sampling years. The lake supports 5 documented fish species including Musky, Panfish, and Largemouth Bass. Public access is available with 1 public boat landing. Compared to the 54 other monitored lakes in Polk County, Bear Trap Lake ranks #32 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-21. Grade methodology: LakeQuality 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 8.8 ft. Phosphorus level: 24.9 µg/L. Trophic State Index: 48.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 8.8 ft | Not graded |
| Phosphorus | 24.9 µg/L | Fair |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 48 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Bear Trap Lake
Compare lakeside cabins, hotels, and vacation rentals near Bear Trap Lake in Polk County, Wisconsin — 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 Bear Trap Lake
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Planning a whole trip? See where to stay at Wisconsin’s top lakes →
Water Temperature
Bear Trap Lake typically sits around 74°F at the surface in August. Summer average is about 75°F. Usually warmest in Jul (about 78°F) and coldest in Sep (about 70°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 28 field readings (2024–2025) via the EPA Water Quality Portal. See the full Bear Trap Lake water temperature breakdown →
Wisconsin DNR lists Panfish as common on Bear Trap Lake.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Bear Trap Lake C from EPA Water Quality Portal chemistry, and the water-quality trend over 7 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 1991. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 25 ft |
| Surface Area | 247 acres |
| Public Access | Yes |
Recreation & Access
- Beartrap LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Bear Trap 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: ↑ Improving
Based on 7 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.607 m/yr | 6 |
| Phosphorus | → Stable | +0.23 µg/L/yr | 7 |
EPA Impairment Status
Bear Trap Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5R).
Causes of impairment
Source: EPA ATTAINS assessment unit WI10004970 · Official waterbody report
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Bear Trap Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Lake Wapogasset Bear Trap Lake S DGarfield · 0.4 mi away · NPDES WI0060313Recent violation
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 #32 of 55 lakes in Polk County
Nearby Lakes in Polk County
Frequently asked questions about Bear Trap Lake
Where is Bear Trap Lake?
- Bear Trap Lake is a lake in Polk County, Wisconsin. LakeQuality grades it C for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Bear Trap Lake?
- Bear Trap Lake in Polk County, Wisconsin has a water quality grade of C (Fair). Water clarity: 8.8 ft visibility. Phosphorus: 24.9 µg/L. Maximum depth: 25 ft. Surface area: 247 acres.
Is Bear Trap Lake safe to swim in?
- Generally safe for swimming, moderate water quality. Bear Trap Lake has a water quality grade of C (Fair). Always check local health department advisories before swimming.
What is the water temperature of Bear Trap Lake?
- Bear Trap Lake typically sits around 74°F at the surface in August, from 28 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.
How deep is Bear Trap Lake?
- Bear Trap Lake has a maximum depth of 25 feet. The lake covers 247 acres.
What fish are in Bear Trap Lake?
- Fish species found in Bear Trap Lake include Musky, Panfish, Largemouth Bass, Northern Pike, Walleye. Bear Trap Lake is located in Polk County, Wisconsin.
What did the DNR fisheries survey find at Bear Trap Lake?
- Wisconsin DNR lists Panfish as common on Bear Trap Lake. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Bear Trap Lake C from EPA Water Quality Portal chemistry, and the water-quality trend over 7 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Bear Trap Lake?
- Bear Trap Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Beartrap Lake. Public access is listed as yes.
Explore Bear Trap Lake across LakeQuality
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Moderate nutrients, good water quality
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Where this data comes from
138 measurements from 1 monitoring station, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX138 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
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 size & watershed from HydroLAKES (HydroSHEDS)
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory