De Neveu Lake
Fond du Lac County, WisconsinMesotrophic
De Neveu Lake earns an A — every scored parameter (clarity and phosphorus) rates among the best monitored waters in Fond du Lac County. clarity and phosphorus rate similarly, so there is no obvious single lever to pull on watershed management.
A TSI near 44 places De Neveu Lake in the mesotrophic band — moderate productivity, with seasonal swings between clearer spring water and richer late-summer conditions. De Neveu Lake is unusually deep for Wisconsin at 67 ft, which buffers the lake against summer warming and helps the deep water stay oxygenated. The lake is compact at 80 acres, with partial shoreline records and little volume to buffer nutrient inputs. De Neveu Lake ranks 3 of 10 in Fond du Lac County — solidly in the upper half of the local distribution.
De Neveu Lake is on the Wisconsin infested-waters list for zebra mussels — boaters should follow clean-drain-dry protocols when moving gear to or from the lake. The fishery includes walleye among the lake's 4 documented species — a notable draw for Wisconsin anglers. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-09-04. Grade methodology: LakeGrade methodology.
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Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
Good clarity, visible to about 11 ft. Phosphorus level: 18.1 µg/L. Trophic State Index: 44.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 11 ft | B |
| Phosphorus | 18.1 µg/L | A |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 44 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 67 ft |
| Surface Area | 80 acres |
Fish Species
Click a species to see all Wisconsin and Minnesota lakes where it is found.
→ Best fishing times for De Neveu Lake (14-day solunar calendar)
→ Is it safe to eat fish from De Neveu Lake? (mercury & PFAS guide)
→ De Neveu Lake fishing regulations (limits, seasons, special rules)
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: ↓ Declining
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -1.097 m/yr | 5 |
| Phosphorus | → Stable | +0.01 µg/L/yr | 5 |
Location
County Ranking
Ranked #3 of 10 lakes in Fond du Lac County
Nearby Lakes in Fond du Lac County
More Wisconsin Lake Rankings
Other Grade A Lakes in Wisconsin
Washington County · Clarity: 11.8 ft
Washington County · Clarity: 12.6 ft
Walworth County · Clarity: 11 ft
Waukesha County · Clarity: 11.3 ft
Walworth County · Clarity: 20.2 ft
Kenosha County · Clarity: 10 ft
Mesotrophic Lakes in Wisconsin
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 2008. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
EPA Impairment Status
De Neveu Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit WI10000952 · Official waterbody report
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Grading methodology based on Metropolitan Council standards
Most recent sample: 2025-09-04
Monitoring stations: 1