Sunfish Lake
Washington County, MinnesotaLimited DataMesotrophic
Sunfish Lake sits at a C on the grading scale — not impaired, not pristine, with summer measurements that vary year to year. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.
The lake sits in the mesotrophic zone — the band where most well-managed Minnesota lakes fall. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. The lake's surface area is not consistently recorded across state datasets — physical context remains partial. Among the 31 graded lakes in Washington County, Sunfish Lake sits at rank 14, above the county median.
Eurasian watermilfoil is established at Sunfish Lake, which can dampen recreational access and pressure the native plant community. The state fisheries records do not list documented species for Sunfish Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. The lake lacks a documented public access point, so visitor use is limited. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-09-27. Grade methodology: LakeGrade methodology.
Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Moderate clarity, visible to about 8.5 ft. Trophic State Index: 46.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 8.5 ft | C |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 46 | Mesotrophic |
Moderate nutrients, good water quality
Invasive Species
Water Quality Trend: ↓ Declining
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.068 m/yr | 5 |
Location
County Ranking
Ranked #14 of 31 lakes in Washington County
Nearby Lakes in Washington County
More Minnesota Lake Rankings
State Parks Near Sunfish Lake
Other Grade C Lakes in Minnesota
Mesotrophic Lakes in Minnesota
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Most recent sample: 2024-09-27
Monitoring stations: 1