Day Lake
Day Lake in Vilas County, Wisconsin has a water quality grade of B (Good). Phosphorus: 10.2 µg/L. Maximum depth: 57 ft. Surface area: 110 acres.
Wisconsin DNR lists Panfish as common on Day Lake. DNR survey details →
- Max depth
- 57 ft
- Area
- 110 acres
- Type
- Oligotrophic
- Trend
- ↓ Declining
- Public access
- Yes
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Day Lake is a 110-acre cold, clear oligotrophic lake in Vilas County, Wisconsin with a maximum depth of 57 feet. Water quality is graded B based on 1 sampling years through 2022. Overall water quality is declining over recent sampling years. The lake supports 2 documented fish species including Panfish and Smallmouth Bass. Public access is available with 2 public boat landings. Compared to the 102 other monitored lakes in Vilas County, Day Lake ranks #84 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2022-09-07. Grade methodology: LakeQuality methodology.
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Swimming Safety
Grade onlyLimited data
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Good for swimming, clear water with low algae levels
Water Quality Grade: B (Good)
No clarity data. Phosphorus level: 10.2 µg/L. Trophic State Index: 38.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 10.2 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 38 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Day Lake
Compare lakeside cabins, hotels, and vacation rentals near Day Lake in Vilas County, Wisconsin — 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.
Top-rated places to stay near Day Lake
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Wisconsin DNR lists Panfish as common on Day Lake.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Day Lake B from EPA Water Quality Portal chemistry, and the water-quality trend over 2 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. 1 station on file (most recent sample 2022).
Fish Species (DNR-rated)
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 57 ft |
| Surface Area | 110 acres |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Diamond LakePublic
- Day LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Day Lake
Water Quality Trend: ↓ Declining
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Phosphorus | ↓ Declining | +1.1 µg/L/yr | 2 |
EPA Impairment Status
Day Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit WI10003879 · Official waterbody report · Matched by proximity (2.95 km)
County Ranking
Ranked #84 of 103 lakes in Vilas County
Nearby Lakes in Vilas County
Frequently asked questions about Day Lake
Where is Day Lake?
- Day Lake is a lake in Vilas County, Wisconsin. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Day Lake?
- Day Lake in Vilas County, Wisconsin has a water quality grade of B (Good). Phosphorus: 10.2 µg/L. Maximum depth: 57 ft. Surface area: 110 acres.
Is Day Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Day Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
How deep is Day Lake?
- Day Lake has a maximum depth of 57 feet. The lake covers 110 acres.
What fish are in Day Lake?
- Fish species found in Day Lake include Panfish, Smallmouth Bass. Day Lake is located in Vilas County, Wisconsin.
What did the DNR fisheries survey find at Day Lake?
- Wisconsin DNR lists Panfish as common on Day Lake. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Day Lake B from EPA Water Quality Portal chemistry, and the water-quality trend over 2 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Day Lake?
- Day Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Diamond Lake, Day Lake. Public access is listed as yes.
Explore Day Lake across LakeQuality
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Where this data comes from
5 measurements from 1 monitoring station, 2021–2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX5 samples · 2021–2022
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory