Fond du Lac County Lake Quality
Wisconsin, 10 lakes, average grade C (Fair)
Only 10 lakes in Fond du Lac County carry an active grade. The county-level summary is therefore representative of those specific lakes, not necessarily of every water body in the county. The county average is C — the middle of the rubric, with one or two lakes pulling the average up or down depending on year.
Most of the county's monitored lakes are shallow — under 50 feet — which means wind keeps the water column mixed all summer and sediment-bound phosphorus releases back into the surface layer whenever the bottom is disturbed. Long Lake (B) is the cleanest in the county.
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Quick Answers for Fond du Lac County
Planning a trip? Check special fishing regulations for Long Lake, whether the fish are safe to eat, and the best times to fish — or browse the full Wisconsin regulations index.
Fishing in Fond du Lac County
DNR Reports (1)
Wisconsin DNR Fisheries Survey resources for lakes in Fond du Lac County. browse all reports →
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- 2023Lakeside Park (Lake Winnebago) spring shocking survey, 2023Spring Shocking Survey · WI DNR · 2023 (PDF)
All Lakes in Fond du Lac County
10 lakes · 9 graded, 1 not rated9 graded lakes · 1 not rated, hidden
| # | Lake | Grade | Clarity | Phosphorus | Algae | Trophic | Max Depth | Access |
|---|---|---|---|---|---|---|---|---|
| 1 | BLong LakeFond du Lac | B | 9.1 ft | 19.3 µg/L | No recent samples | No recent samples | 47 ft | ✓ Public |
| 2 | BWolf LakeFond du Lac | B | 5 ft | 31 µg/L | No recent samples | No recent samples | 47 ft | ✓ Public |
| 3 | BForest LakeFond du Lac | B | 14 ft | 14.1 µg/L | No recent samples | No recent samples | 32 ft | ✓ Public |
| 4 | BAuburn LakeFond du Lac | B | 7.6 ft | 24.4 µg/L | No recent samples | No recent samples | 29 ft | ✓ Public |
| 5 | BKettle Moraine LakeFond du Lac | B | 11 ft | 16.2 µg/L | No recent samples | No recent samples | 30 ft | Not recorded |
| 6 | BDe Neveu LakeFond du Lac | B | 11 ft | 18.1 µg/L | No recent samples | No recent samples | 67 ft | Not recorded |
| 7 | CMauthe LakeFond du Lac | C | 6 ft | 54 µg/L | No recent samples | No recent samples | 23 ft | ✓ Public |
| 8 | DBernice LakeFond du Lac | D | 6.5 ft | 74.9 µg/L | No recent samples | No recent samples | 11 ft | Not recorded |
| 9 | DGiltners LakeFond du Lac | D | No recent samples | 171 µg/L | No recent samples | No recent samples | 13 ft | Not recorded |
| NRDickman LakeFond du Lac | NR | No recent samples | No recent samples | No recent samples | No recent samples | 12 ft | Not recorded |
NR = not rated: the monitoring record does not meet the evidence bar for a grade. That is EPA Integrated Reporting Category 3 (insufficient information), not a failing grade. How grading works.
Lake Match
Which lake suits how you actually use one?
Six questions — swimming, fishing, quiet, cabins, drive time — and a shortlist of graded lakes that fit, with the water quality behind each one.
Other Counties in Wisconsin
See how Fond du Lac County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 39 states and 2 Canadian provinces.
Source: EPA National Aquatic Resource Surveys, 2026.