Big Lake
Big Lake in Polk County, Wisconsin has a water quality grade of B (Good). Water clarity: 9 ft visibility. Phosphorus: 21.6 µg/L. Maximum depth: 24 ft. Surface area: 245 acres.
Wisconsin DNR lists Panfish as common on Big Lake. DNR survey details →
- Clarity
- 9 ft
- Max depth
- 24 ft
- Area
- 245 acres
- Type
- Mesotrophic
- Trend
- ↑ Improving
- Public access
- Yes
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Big Lake is a 245-acre mesotrophic lake in Polk County, Wisconsin with a maximum depth of 24 feet. Water quality is graded B based on 1 sampling years through 2025. Overall water quality is improving over recent sampling years. The lake supports 4 documented fish species including Panfish, Largemouth Bass, and Northern Pike. Public access is available. Compared to the 54 other monitored lakes in Polk County, Big Lake ranks #9 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-09-01. Grade methodology: LakeQuality methodology.
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Swimming Safety
Grade onlyLow algae
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.
Good for swimming, clear water with low algae levels
Water Quality Grade: B (Good)
Moderate clarity, visible to about 9 ft. Phosphorus level: 21.6 µg/L. Trophic State Index: 47.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 9 ft | Not graded |
| Phosphorus | 21.6 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 47 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Big Lake
Compare lakeside cabins, hotels, and vacation rentals near Big 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 Big Lake
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Wisconsin DNR lists Panfish as common on Big Lake.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Big Lake B from EPA Water Quality Portal chemistry, and the water-quality trend over 6 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 1986. 7 stations on file (most recent sample 2025).
Fish Species (DNR-rated)
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 24 ft |
| Surface Area | 245 acres |
| Public Access | Yes |
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Big 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 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.014 m/yr | 6 |
| Phosphorus | ↑ Improving | -0.63 µg/L/yr | 6 |
EPA Impairment Status
Big 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 WI10004943 · Official waterbody report · Matched by proximity (1.33 km)
County Ranking
Ranked #9 of 55 lakes in Polk County
Nearby Lakes in Polk County
Frequently asked questions about Big Lake
Where is Big Lake?
- Big Lake is a lake in Polk County, Wisconsin. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Big Lake?
- Big Lake in Polk County, Wisconsin has a water quality grade of B (Good). Water clarity: 9 ft visibility. Phosphorus: 21.6 µg/L. Maximum depth: 24 ft. Surface area: 245 acres.
Is Big Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Big Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
How deep is Big Lake?
- Big Lake has a maximum depth of 24 feet. The lake covers 245 acres.
What fish are in Big Lake?
- Fish species found in Big Lake include Panfish, Largemouth Bass, Northern Pike, Walleye. Big Lake is located in Polk County, Wisconsin.
What did the DNR fisheries survey find at Big Lake?
- Wisconsin DNR lists Panfish as common on Big Lake. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Big Lake B from EPA Water Quality Portal chemistry, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
Explore Big Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
Fish species and top-graded lakes across Wisconsin
Fish species and best lakes in Polk County
Species activity outlook by water temperature and season
Where to stay at Wisconsin's top lakes, each with its grade
Lakes in the St. Croix Watershed, ranked by water quality
Moderate nutrients, good water quality
Wisconsin's cleanest and most-polluted lakes, ranked
More Wisconsin Lake Rankings
State Parks Near Big Lake
Other Grade B Lakes in Wisconsin
Mesotrophic Lakes in Wisconsin
Where this data comes from
86 measurements from 2 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX86 samples · 2020–2025
Analytical methods
- Phosphorus by Colorimetry
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)
Fish and recreation data from Wisconsin DNR Lakes