Otter Lake
Vilas County, Wisconsin174 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Otter Lake. Here is what has been measured.
- Eutrophic
- Impaired · Nutrients (phosphorus, nitrogen)
- Rusty Crayfish
- 30 ft max depth
- Public access
- Limited data
Otter Lake in Vilas County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 5 ft visibility. Phosphorus: 30.8 µg/L. Maximum depth: 30 ft. Surface area: 174 acres.
Wisconsin DNR lists Musky as common on Otter Lake. DNR survey details →
Otter Lake is a 174-acre productive, nutrient-rich eutrophic lake in Vilas County, Wisconsin with a maximum depth of 30 feet. The lake supports 6 documented fish species including Musky, Panfish, and Largemouth Bass. Public access is available. Compared to the 102 other monitored lakes in Vilas County, Otter Lake ranks #97 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-10-18. Methodology: how these readings are compared.
What Otter Lake is good for
From access and monitoring records, not editorial picks.
- Fishing6 species recorded
- Deep water30 ft surveyed max depth
Swimming conditions
Readings onlyRecreation use not supported
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Otter Lake is listed impaired under Clean Water Act §303(d) (IR 5) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Otter Lake is safe to swim in today is a call for the Wisconsin Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Otter Lake
These are the measurements Wisconsin DNR publishes for Otter Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 5 ft. Phosphorus 30.8 µg/L. TSI 54.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 30.8µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 54 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Otter Lake
Answers come straight from the public measurements and survey records on this page.
Wisconsin DNR lists Musky as common on Otter Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Otter Lake’s water-quality measurements separately, and the water-quality trend over 7 years of monitoring is stable. 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. Monitored by volunteers since 1993. 2 stations on file (most recent sample 2025).
Fish Species (DNR-rated)
Lake Details
Max depth
30 ft
Surface area
174 acres
Public access
Yes
Listed by Wisconsin DNR
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Stays near Otter Lake
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Fish Species
Click a species to see every lake where it is documented.
Fishing Otter Lake
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: Stable
Based on 7 years of monitoring (2020–2026).
Water clarity
Stable7 years
EPA Impairment Status
Otter Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Aquatic life, Recreation.
Source: EPA ATTAINS assessment unit WI10007690 · Official waterbody report
Nearby Lakes in Vilas County
Frequently asked questions about Otter Lake
Where is Otter Lake?
- Otter Lake is a lake in Vilas County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Otter Lake?
- Otter Lake in Vilas County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 5 ft visibility. Phosphorus: 30.8 µg/L. Maximum depth: 30 ft. Surface area: 174 acres.
Is Otter Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Otter Lake is listed impaired under Clean Water Act §303(d) (IR 5) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
How deep is Otter Lake?
- Otter Lake has a maximum depth of 30 feet. The lake covers 174 acres.
What fish are in Otter Lake?
- Fish species found in Otter Lake include Musky, Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Walleye. Otter Lake is located in Vilas County, Wisconsin.
What did the DNR fisheries survey find at Otter Lake?
- Wisconsin DNR lists Musky as common on Otter Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Otter Lake’s water-quality measurements separately, and the water-quality trend over 7 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
Can I fish at Otter Lake?
- Public access to Otter Lake is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by Wisconsin's fish and wildlife agency, so check its current regulations before you go.
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Where this data comes from
32 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX32 samples · 2020–2025
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Fish and recreation data from Wisconsin DNR Lakes