Big Twin Lake
Big Twin Lake in Green Lake County, Wisconsin is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 7 ft visibility.
- Clarity
- 7 ft
- Max depth
- ~45 ft est.
- Public access
- Yes
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Why Big Twin Lake has no grade
We grade a lake only when the monitoring record supports a letter: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Big Twin Lake, the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity. Sampling here has recorded water clarity, but not phosphorus and algae (chlorophyll-a).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by WI DNR and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Big Twin Lake is a lake in Green Lake County, Wisconsin with an estimated average depth of about 45 feet. Limited fish-species data available. Public access is available with 2 public boat landings.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2024-10-11. Grade methodology: LakeQuality methodology.
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Big Twin Lake
These readings exist but are not enough for an A–F grade — see why.
Moderate clarity, visible to about 7 ft. Trophic State Index: 49.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 7 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 49 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Big Twin Lake
Compare lakeside cabins, hotels, and vacation rentals near Big Twin Lake in Green Lake 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 Twin Lake
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DNR Reports & Resources
Wisconsin DNR Fisheries scientists publish multi-year survey reports for Big Twin Lake covering fish populations, stocking, water quality, and management. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- 2023Big Twin Lake spring shocking survey, 2023Spring Shocking Survey · WI DNR · 2023 (PDF)
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~45 ft est. |
| Average Depth | ~13 ft est. |
| Public Access | Yes |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Wisconsin has not published bathymetry for Big Twin 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.
Recreation & Access
- Twin Lakes County ParkPublic
- Spring Lake County ParkPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Big Twin Lake
EPA Impairment Status
Big Twin Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit WI10000971 · Official waterbody report
Graded lakes near Big Twin Lake
Big Twin Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Green Lake County
Frequently asked questions about Big Twin Lake
Where is Big Twin Lake?
- Big Twin Lake is a lake in Green Lake County, Wisconsin. LakeQuality has not rated this lake (UNRATED) — there is not enough recent sampling to assign a letter.
What is the water quality grade for Big Twin Lake?
- Big Twin Lake in Green Lake County, Wisconsin is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 7 ft visibility.
Is Big Twin Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Big Twin Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
How deep is Big Twin Lake?
- No published bathymetric survey covers Big Twin Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 45 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Are there boat ramps on Big Twin Lake?
- Big Twin Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Twin Lakes County Park, Spring Lake County Park. Public access is listed as yes.
Explore Big Twin Lake across LakeQuality
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Where this data comes from
16 measurements from 1 monitoring station, 2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX16 samples · 2024
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Named boat-access points from the USGS National Boat Ramps inventory