Williams Lake
Marquette County, WisconsinView mapDirections
Wisconsin DNR publishes the water-quality measurements for Williams Lake. Here is what has been measured.
- Mesotrophic
- 37 ft max depth
- Public access
Williams Lake in Marquette County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 6 ft visibility. Phosphorus: 21.4 µg/L.
Williams Lake is a mesotrophic lake in Marquette County, Wisconsin with an estimated average depth of about 37 feet. 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 10 other monitored lakes in Marquette County, Williams Lake ranks #6 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-08-17. Methodology: how these readings are compared.
What Williams Lake is good for
From access and monitoring records, not editorial picks.
- 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 Williams 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 Williams Lake
These are the measurements Wisconsin DNR publishes for Williams Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 6 ft. Phosphorus 21.4 µg/L. TSI 50.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 6ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 21.4µg/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. | 50 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Williams Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~37 ft est.
Public access
Yes
Listed by Wisconsin DNR
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Wisconsin has not published bathymetry for Williams Lake.
Lake Size & Watershed
Watershed (drainage) area
1 sq mi
HydroLAKES / HydroSHEDS
Surface area
74 acres
HydroLAKES / HydroSHEDS
Shoreline
2.4 mi
HydroLAKES / HydroSHEDS
Elevation
784 ft
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
- Williams 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 Williams Lake
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Fishing Williams Lake
Water Quality Trend: Stable
Based on 6 years of monitoring (2020–2025).
Water clarity
Worsening5 years
Phosphorus
Improving-1.25 µg/L/yr6 years
Nearby Lakes in Marquette County
Frequently asked questions about Williams Lake
Where is Williams Lake?
- Williams Lake is a lake in Marquette County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Williams Lake?
- Williams Lake in Marquette County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 6 ft visibility. Phosphorus: 21.4 µg/L.
Is Williams Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Williams Lake?
- No published bathymetric survey covers Williams Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 37 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 Williams Lake?
- Williams Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Williams Lake. Public access is listed as yes.
Can I fish at Williams Lake?
- Williams 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 Williams Lake across LakeQuality
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Where this data comes from
46 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_WQX46 samples · 2020–2025
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Named boat-access points from the USGS National Boat Ramps inventory