Bass Lake
St. Croix County, WisconsinView mapDirections
Wisconsin DNR publishes the water-quality measurements for Bass Lake. Here is what has been measured.
- Mesotrophic
- Public access
Bass Lake in St. Croix County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 10 ft visibility. Phosphorus: 14 µg/L.
Bass Lake is a mesotrophic lake in St. Croix County, Wisconsin. Water clarity is declining over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 4 other monitored lakes in St. Croix County, Bass Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-04-22. Methodology: how these readings are compared.
What Bass Lake is good for
From access and monitoring records, not editorial picks.
- Clear water10 ft of visibility
- Boat launch1 documented ramp
Swimming conditions
Readings onlyLow algae
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Bass Lake is safe to swim in today is a call for the Wisconsin Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Bass Lake
These are the measurements Wisconsin DNR publishes for Bass Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Good clarity, visible to about 10 ft. Phosphorus 14 µg/L. TSI 43.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 10ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 14µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 43 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Bass Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Bass Lake typically sits around 70°F at the surface in September. Summer average is about 76°F. Usually warmest in Jul (about 79°F) and coldest in Sep (about 70°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (70°F) to its warmest (79°F).
Typical surface water temperature by month, from 33 field readings (2024–2025) via the EPA Water Quality Portal. See the full Bass Lake water temperature breakdown →
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 (205,116 cells/mL) on April 11, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Recreation & Access
- Bass LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Bass Lake
Compare lakeside cabins, hotels, and vacation rentals near Bass Lake in St. Croix 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 Bass Lake
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Fishing Bass Lake
Water Quality Trend: Stable
Based on 6 years of monitoring (2020–2025).
Water clarity
Worsening6 years
Phosphorus
Improving-0.8 µg/L/yr6 years
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Bass Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Somerset Wastewater Treatment FacilitySomerset · 3 mi away · NPDES WI0030252Recent 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.
Nearby Lakes in St. Croix County
Frequently asked questions about Bass Lake
Where is Bass Lake?
- Bass Lake is a lake in St. Croix County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Bass Lake?
- Bass Lake in St. Croix County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 10 ft visibility. Phosphorus: 14 µg/L.
Is Bass Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Bass Lake?
- Bass Lake typically sits around 70°F at the surface in September, from 33 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.
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 (205,116 cells/mL). Blue-green algae can appear and clear within days, so check Wisconsin's current advisory before swimming.
Are there boat ramps on Bass Lake?
- Bass Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Bass Lake. Public access is listed as yes.
Can I fish at Bass Lake?
- Bass Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Wisconsin's fish and wildlife agency, so check its current regulations before you go.
Explore Bass Lake across LakeQuality
4.3 mi away · 45 ft
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Fish species and best lakes in St. Croix County
Species activity outlook by water temperature and season
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Lakes in the St. Croix Watershed, ranked by water quality
Wisconsin's cleanest lakes, ranked on agency measurements
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Mesotrophic Lakes in Wisconsin
Where this data comes from
99 measurements from 2 monitoring stations, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX99 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (2)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Named boat-access points from the USGS National Boat Ramps inventory