Willis Lake is a cold, clear oligotrophic lake in Hamilton County, New York. Water quality is graded A based on 1 sampling years through 2023. Overall water quality is improving over recent sampling years. Compared to the 6 other monitored lakes in Hamilton County, Willis Lake ranks #5 for water quality.
Source: EPA Water Quality Portal sampling records, New York DNR, last sampled 2023-07-12. Grade methodology: LakeGrade methodology.
Watch Willis Lake water quality
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Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
No clarity data. Phosphorus level: 8 µg/L. Trophic State Index: 34.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No data | |
| Phosphorus | 8 µg/L | A |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 34 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Willis Lake
Compare lakeside cabins, hotels, and vacation rentals near Willis Lake in Hamilton County, New York — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
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Fishing Willis Lake
Water Quality Trend: ↑ Improving
Based on 3 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Phosphorus | ↑ Improving | -0.5 µg/L/yr | 3 |
Location
County Ranking
Ranked #5 of 7 lakes in Hamilton County
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Low nutrients, clear water, excellent for swimming
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Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Willis Lake under Clean Water Act (NPDES) discharge permits.
- Sacandaga CampgroundWells · 2.1 mi away · NPDES NY0034371
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Data Sources
Water quality data from the EPA Water Quality Portal
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Grading methodology based on Metropolitan Council standards
Most recent sample: 2023-07-12
Monitoring stations: 1