Big Lake
Big Lake in Shawano County, Wisconsin has a water quality grade of A (Excellent). Water clarity: 8 ft visibility. Phosphorus: 15 µg/L. Chlorophyll-a (algae): 2.7 µg/L.
- Clarity
- 8 ft
- Typical in July
- 65°F
- Mean depth
- ~9 ft est.
- Type
- Mesotrophic
- Trend
- ↑ Improving
Next lake in Shawano County
Big Lake is a mesotrophic lake in Shawano County, Wisconsin with an estimated average depth of about 9 feet. Water quality is graded A based on 2 sampling years through 2026. Overall water quality is improving over recent sampling years. Compared to the 20 other monitored lakes in Shawano County, Big Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-22. Grade methodology: LakeGrade 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.
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A (Excellent)
Moderate clarity, visible to about 8 ft. Phosphorus level: 15 µg/L. Chlorophyll-a: 2.7 µg/L. Trophic State Index: 44.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 8 ft | Not graded |
| Phosphorus | 15 µg/L | Good |
| Chlorophyll-a (Algae) | 2.7 µg/L | Good |
| Trophic State Index (TSI) | 44 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Big Lake
Compare lakeside cabins, hotels, and vacation rentals near Big Lake in Shawano 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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Water Temperature
Big Lake typically sits around 65°F at the surface in July. Summer average is about 59°F. Usually warmest in Sep (about 66°F) and coldest in May (about 49°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 134 field readings (2024–2025) via the EPA Water Quality Portal. See the full Big Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Average Depth | ~9 ft est. |
Depth marked “est.” is a modeled estimate from HydroLAKES, not a measured survey. Wisconsin has not published bathymetry for Big Lake.
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Fishing Big Lake
Water Quality Trend: ↑ Improving
Based on 7 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.664 m/yr | 6 |
| Phosphorus | → Stable | -0.24 µg/L/yr | 7 |
| Chlorophyll-a | ↑ Improving | -0.45 µg/L/yr | 2 |
Regulated Pollution Sources Nearby
3 EPA-permitted facilities operate within about 5 miles of Big Lake under Clean Water Act (NPDES) discharge permits. 3 facilities have a reported Clean Water Act violation in the past three years.
- Wolf River Ranch WwtfShawano County · 0.8 mi away · NPDES WI0071307Recent violation
- Menominee Tribal EnterpriseNeopit · 3.3 mi away · NPDES WI0046868Recent violation
- Newburg VillageNewburg · 4.9 mi away · NPDES WI0024911Recent 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 #1 of 21 lakes in Shawano County
Nearby Lakes in Shawano County
Frequently asked questions about Big Lake
What is the water quality grade for Big Lake?
- Big Lake in Shawano County, Wisconsin has a water quality grade of A (Excellent). Water clarity: 8 ft visibility. Phosphorus: 15 µg/L. Chlorophyll-a (algae): 2.7 µg/L.
Is Big Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Big Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 2.7 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Big Lake?
- Big Lake typically sits around 65°F at the surface in July, from 134 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.
How deep is Big Lake?
- No published bathymetric survey covers Big Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 9 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Explore Big Lake across LakeGrade
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Moderate nutrients, good water quality
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Where this data comes from
94 measurements from 4 monitoring stations, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Stockbridge_Munsee Community
STOCKBRIDGE_MUNSEE63 samples · 2021–2025 - Wisconsin Department of Natural Resources
WIDNR_WQX31 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
- 4500 P E ~ Phosphorus in Water by Colorimetry- Ascorbic Acid Method
- 10200 H ~ Chlorophyll a-b-c Determination
- Phosphorus in Water by Colorimetry- Ascorbic Acid Method
Monitoring station identifiers (4)
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)