South Twin Lake
South Twin Lake in Washburn County, Wisconsin has a water quality grade of B (Good). Water clarity: 14 ft visibility. Phosphorus: 11.5 µg/L. Maximum depth: 29 ft. Surface area: 106 acres.
Wisconsin DNR rates Panfish as abundant on South Twin Lake. DNR survey details →
- Clarity
- 14 ft
- Typical in August
- 73°F
- Max depth
- 29 ft
- Area
- 106 acres
- Type
- Oligotrophic
- Trend
- → Stable
- Public access
- Yes
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South Twin Lake is a 106-acre cold, clear oligotrophic lake in Washburn County, Wisconsin with a maximum depth of 29 feet. Water quality is graded B based on 1 sampling years through 2025. The lake supports 4 documented fish species including Panfish, Largemouth Bass, and Northern Pike. Public access is available with 2 public boat landings. Compared to the 26 other monitored lakes in Washburn County, South Twin Lake ranks #16 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-08-17. 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)
Good clarity, visible to about 14 ft. Phosphorus level: 11.5 µg/L. Trophic State Index: 39.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 14 ft | Not graded |
| Phosphorus | 11.5 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 39 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near South Twin Lake
Compare lakeside cabins, hotels, and vacation rentals near South Twin Lake in Washburn 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 South Twin Lake
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Planning a whole trip? See where to stay at Wisconsin’s top lakes →
Water Temperature
South Twin Lake typically sits around 73°F at the surface in August. Summer average is about 76°F. Usually warmest in Jul (about 79°F) and coldest in Aug (about 73°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 12 field readings (2024–2025) via the EPA Water Quality Portal. See the full South Twin Lake water temperature breakdown →
Wisconsin DNR rates Panfish as abundant on South Twin Lake.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades South Twin Lake B from EPA Water Quality Portal chemistry, and the water-quality trend over 6 years of monitoring is stable. 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 1994. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 29 ft |
| Surface Area | 106 acres |
| Public Access | Yes |
Recreation & Access
- South Twin LakePublic
- Pear 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 South Twin 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: → Stable
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | -0.113 m/yr | 6 |
| Phosphorus | → Stable | -0.07 µg/L/yr | 6 |
County Ranking
Ranked #16 of 27 lakes in Washburn County
Nearby Lakes in Washburn County
Frequently asked questions about South Twin Lake
Where is South Twin Lake?
- South Twin Lake is a lake in Washburn County, Wisconsin. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for South Twin Lake?
- South Twin Lake in Washburn County, Wisconsin has a water quality grade of B (Good). Water clarity: 14 ft visibility. Phosphorus: 11.5 µg/L. Maximum depth: 29 ft. Surface area: 106 acres.
Is South Twin Lake safe to swim in?
- Good for swimming, clear water with low algae levels. South Twin Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
What is the water temperature of South Twin Lake?
- South Twin Lake typically sits around 73°F at the surface in August, from 12 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.
How deep is South Twin Lake?
- South Twin Lake has a maximum depth of 29 feet. The lake covers 106 acres.
What fish are in South Twin Lake?
- Fish species found in South Twin Lake include Panfish, Largemouth Bass, Northern Pike, Walleye. South Twin Lake is located in Washburn County, Wisconsin.
What did the DNR fisheries survey find at South Twin Lake?
- Wisconsin DNR rates Panfish as abundant on South Twin Lake. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades South Twin Lake B from EPA Water Quality Portal chemistry, and the water-quality trend over 6 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on South Twin Lake?
- South Twin Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include South Twin Lake, Pear Lake. Public access is listed as yes.
Explore South Twin Lake across LakeQuality
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Where this data comes from
31 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX31 samples · 2020–2025
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
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