School Section Lake
Waukesha County, WisconsinMesotrophic
On the LakeGrade rubric, School Section Lake pulls an A: clarity at 16.7 ft and 26 µg/L of phosphorus put it in the top bracket for Wisconsin. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.
Mesotrophic conditions dominate at School Section Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. At 122 acres, School Section Lake fits the Wisconsin median for monitored lakes, with partial shoreline records. Within Waukesha County's 48 graded lakes, School Section Lake ranks 34 — below the local median, though not at the bottom.
School Section Lake carries an invasive watermilfoil record — boat-launch decontamination and shoreline care matter more here than at uninfested lakes. Bass fishing is part of the appeal: the species list runs to 3, anchored by largemouth and/or smallmouth bass. Public access is available — the lake is on the Wisconsin DNR public-access list. 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 2025-11-23. Grade methodology: LakeGrade methodology.
Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
Crystal clear, you can see 16.7 ft down. Phosphorus level: 26.2 µg/L. Trophic State Index: 44.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 16.7 ft | A |
| Phosphorus | 26.2 µg/L | B |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 44 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 122 acres |
| Public Access | Yes |
Fish Species
Click a species to see all Wisconsin and Minnesota lakes where it is found.
→ Best fishing times for School Section Lake (14-day solunar calendar)
→ Is it safe to eat fish from School Section Lake? (mercury & PFAS guide)
→ School Section Lake fishing regulations (limits, seasons, special rules)
Invasive Species
Water Quality Trend: ↑ Improving
Based on 7 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.575 m/yr | 7 |
| Phosphorus | ↑ Improving | -1.79 µg/L/yr | 6 |
Recreation & Access
Location
County Ranking
Ranked #34 of 48 lakes in Waukesha County
Nearby Lakes in Waukesha County
More Wisconsin Lake Rankings
State Parks Near School Section Lake
Other Grade A Lakes in Wisconsin
Walworth County · Clarity: 19 ft
Washington County · Clarity: 12 ft
Kenosha County · Clarity: 10.1 ft
Washington County · Clarity: 12.5 ft
Walworth County · Clarity: 10.8 ft
Walworth County · Clarity: 11 ft
Mesotrophic Lakes in Wisconsin
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. 2 stations on file (most recent sample 2026).
Fish Species (DNR-rated)
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Fish and recreation data from Wisconsin DNR Lakes
Most recent sample: 2025-11-23
Monitoring stations: 1