Pierce County Lake Quality
Wisconsin, 2 lakes, average grade C (Fair)
Only 2 lakes in Pierce 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. Pierce County averages to a C. The distribution behind that average matters more than the letter: a few stressed lakes versus many decent ones can produce the same average as the inverse.
Many of the county's lakes are deep glacial basins — over 50 feet at their deepest point — which gives them thermal stratification and a buffer against summer warming. Nugget Lake (grade B) is the cleanest in the county.
Quick Answers for Pierce County
Planning a trip? Check special fishing regulations for Nugget Lake, whether the fish are safe to eat, and the best times to fish — or browse the full Wisconsin regulations index.
All Lakes in Pierce County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Nugget Lake | B | 8.2 ft | - | 27.4 µg/L |
| 2 | St. Croix 8 Mi. Upstream of Point Douglas Dr Lake | C | 8.9 ft | 60 ft | 51 µg/L |
Source: EPA National Aquatic Resource Surveys, 2026.