Jefferson Lake vs Washington Lake
Water quality, depth, fish species, and recreation comparison.
Jefferson Lake and Washington Lake both received the same overall water quality grade of F (Very Poor). Both are in Le Sueur County, Minnesota.
Jefferson Lake and Washington Lake are both in Minnesota — 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 close: Jefferson Lake (F) and Washington Lake (F) are within one letter of each other on the LakeGrade rubric. The per-parameter sub-grades below will show where the small differences actually live.
With grades this close, the choice between the two lakes turns on non-water-quality factors: depth, fish species, public access, distance from home. The per-lake pages below cover all of those.
Jefferson Lake
Very murky, less than 2 ft of visibility.
Washington Lake
Murky, only visible to about 4.5 ft.
Side-by-Side Metrics
| Metric | Jefferson Lake | Washington Lake |
|---|---|---|
| Overall Grade | F (Very Poor) | F (Very Poor) |
| Water Clarity | 2 ft | 4.5 ft |
| Phosphorus | 86.5 µg/L | 122 µg/L |
| Chlorophyll-a (Algae) | 72 µg/L | 51.3 µg/L |
| Maximum Depth | - | 51 ft |
| Surface Area | 700 acres | 1,516 acres |
| Public Access | Yes | Yes |
| Fish Species | 0 | 18 |
| Trophic State | eutrophic | eutrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Both lakes earn the same Grade F. The tiebreakers come down to clarity (Jefferson Lake: 2 ft, Washington Lake: 4.5 ft) and what you want from the lake. Jefferson Lake has fewer fish species than Washington Lake.
Source: EPA National Aquatic Resource Surveys, 2026.