Fay Lake
Florence County, WisconsinMesotrophic
Fay Lake comes in at a B on the grading rubric — a respectable showing for a Wisconsin lake of its size and depth. Clarity is the limiting factor — phosphorus is reasonable but suspended particles or algal cells keep water transparency below Wisconsin norms.
The lake sits in the mesotrophic zone — the band where most well-managed Wisconsin lakes fall. A maximum depth of just 10 ft means sediment-bound phosphorus releases back into the water column whenever wind stirs the bottom — a classic shallow-lake dynamic. At 272 acres, Fay Lake fits the Wisconsin median for monitored lakes, with partial shoreline records. Fay Lake ranks 16 of 39 in Florence County — solidly in the upper half of the local distribution.
An invasive species record — Banded Mystery Snail — has been logged at Fay Lake; Wisconsin DNR maintains the official infested-waters list. The fishery includes walleye alongside the lake's other 4 documented species — a notable draw for Wisconsin anglers. A documented public access point at Fay Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. 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, Wisconsin DNR Surface Water, last sampled 2025-08-25. Grade methodology: LakeGrade methodology.
Watch Fay Lake water quality
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Swimming Safety
Good for swimming, clear water with low algae levels
Water Quality Grade: B, Good
Moderate clarity, visible to about 7 ft. Phosphorus level: 15.5 µg/L. Trophic State Index: 46.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 7 ft | C |
| Phosphorus | 15.5 µg/L | A |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 46 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 10 ft |
| Surface Area | 272 acres |
| Public Access | Yes |
Fish Species
Click a species to see every graded lake where it is documented.
→ Best fishing times for Fay Lake (14-day solunar calendar)
→ Is it safe to eat fish from Fay Lake? (mercury & PFAS guide)
→ Fay Lake fishing regulations (limits, seasons, special rules)
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.324 m/yr | 6 |
Recreation & Access
Location
County Ranking
Ranked #16 of 39 lakes in Florence County
Cleaner Lakes Within 30 Miles
Fay Lake holds Grade B. 3 nearby lakes hold higher grades.
- ALost LakeFlorence County · mi · Higher grade (B → A)
- APorcupine LakeFlorence County · mi · Higher grade (B → A)
- APatten LakeFlorence County · mi · Higher grade (B → A)
Nearby Lakes in Florence County
More Wisconsin Lake Rankings
Other Grade B Lakes in Wisconsin
Mesotrophic Lakes in Wisconsin
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 2006. 1 station on file (most recent sample 2025).
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
Public boat-access points from the USGS National Boat Ramps inventory
Most recent sample: 2025-08-25
Monitoring stations: 1
Where to stay near Fay Lake
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