Delavan Lake vs Outlet To Lake Geneva
Water quality, depth, fish species, and recreation comparison.
Delavan Lake has a higher water quality grade (B, Good) than Outlet To Lake Geneva (D, Poor). Both are in Walworth County, Wisconsin.
Delavan Lake and Outlet To Lake Geneva are both in Wisconsin — a same-state head-to-head where the comparison comes down to lake-specific differences in depth, watershed, and monitoring history rather than the broader state-level water-quality regime. The grades are meaningfully apart: Delavan Lake grades a B while Outlet To Lake Geneva grades a D. That two-letter spread reflects real underlying differences — different watershed inputs, different depth profiles, or different monitoring rigor.
For a recreational visitor, the wider grade gap is decisive — Delavan Lake is the better water-quality choice. For a researcher, the gap is the interesting part: what is different about the two watersheds, and which of those differences is mutable?
Delavan Lake
No clarity data.
Outlet To Lake Geneva
No clarity data.
Side-by-Side Metrics
| Metric | Delavan Lake | Outlet To Lake Geneva |
|---|---|---|
| Overall Grade | B (Good) | D (Poor) |
| Water Clarity | No data | No data |
| Phosphorus | 25.9 µg/L | 658 µg/L |
| Chlorophyll-a (Algae) | No data | No data |
| Maximum Depth | 52 ft | 135 ft |
| Surface Area | 1,906 acres | 5,401 acres |
| Public Access | Yes | Yes |
| Fish Species | 6 | 6 |
| Trophic State | eutrophic | hypereutrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Delavan Lake wins on overall water quality with a Grade B versus Outlet To Lake Geneva's Grade D. For fishing diversity, Delavan Lake also leads with 6 species.
Source: EPA National Aquatic Resource Surveys, 2026.