Plum Lake
Vilas County, Wisconsin1,057 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Plum Lake. Here is what has been measured.
- Oligotrophic
- 2 aquatic invasives
- 57 ft max depth
- Public access
Plum Lake in Vilas County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 14.2 ft visibility. Phosphorus: 13 µg/L. Maximum depth: 57 ft. Surface area: 1057 acres.
Wisconsin DNR lists Musky as common on Plum Lake. DNR survey details →
Plum Lake is a 1,057-acre cold, clear oligotrophic lake in Vilas County, Wisconsin with a maximum depth of 57 feet. Overall water quality is declining over recent sampling years. The lake supports 6 documented fish species including Musky, Panfish, and Largemouth Bass. Public access is available with 2 public boat landings. Compared to the 102 other monitored lakes in Vilas County, Plum Lake ranks #7 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-07-04. Methodology: how these readings are compared.
What Plum Lake is good for
From access and monitoring records, not editorial picks.
- Clear water14.2 ft of visibility
- Boat launch2 documented ramps
- Fishing6 species recorded
- Deep water57 ft surveyed max depth
- Big water1,057 acres
Swimming conditions
Readings onlyLow algae
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. Check local advisories before you swim.
Whether Plum 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 Plum Lake
These are the measurements Wisconsin DNR publishes for Plum Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Good clarity, visible to about 14.2 ft. Phosphorus 13 µg/L. TSI 40.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 14.2ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 13µg/L | Good 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. | 40 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Plum Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Plum Lake typically sits around 72°F at the surface in August. Summer average is about 71°F. Usually warmest in Jul (about 75°F) and coldest in Jun (about 67°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (67°F) to its warmest (75°F).
Typical surface water temperature by month, from 17 field readings (2024–2026) via the EPA Water Quality Portal. See the full Plum Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Plum Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was high (619,441 cells/mL) on November 22, 2025.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Wisconsin DNR lists Musky as common on Plum Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Plum Lake’s water-quality measurements separately, and the water-quality trend over 7 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. Monitored by volunteers since 1990. 12 stations on file (most recent sample 2025).
Fish Species (DNR-rated)
DNR Reports & Resources
Wisconsin DNR Fisheries scientists publish multi-year survey reports for Plum Lake covering fish populations, stocking, water quality, and management. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- 2024Plum Lake spring survey, 2024Fisheries Survey · WI DNR · 2024 (PDF)
Lake Details
Max depth
57 ft
Surface area
1,057 acres
Public access
Yes
Listed by Wisconsin DNR
Lake Size & Watershed
Watershed (drainage) area
29 sq mi
HydroLAKES / HydroSHEDS
Shoreline
13.3 mi
HydroLAKES / HydroSHEDS
Elevation
1,631 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Plum LakePublic
- Plum LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Plum Lake
Compare lakeside cabins, hotels, and vacation rentals near Plum 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 Plum Lake
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Planning a whole trip? See where to stay at Wisconsin’s top lakes →
Follow Plum Lake’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing Plum 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: Worsening
Based on 7 years of monitoring (2020–2026).
Water clarity
Stable7 years
Phosphorus
Worsening+2.56 µg/L/yr5 years
Nearby Lakes in Vilas County
Frequently asked questions about Plum Lake
Where is Plum Lake?
- Plum 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 Plum Lake?
- Plum Lake in Vilas County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 14.2 ft visibility. Phosphorus: 13 µg/L. Maximum depth: 57 ft. Surface area: 1057 acres.
Is Plum Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Plum Lake?
- Plum Lake typically sits around 72°F at the surface in August, from 17 EPA Water Quality Portal field readings (2024–2026). That is a typical value for the month, not a live reading.
How deep is Plum Lake?
- Plum Lake has a maximum depth of 57 feet. The lake covers 1057 acres.
What fish are in Plum Lake?
- Fish species found in Plum Lake include Musky, Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Walleye. Plum Lake is located in Vilas County, Wisconsin.
What did the DNR fisheries survey find at Plum Lake?
- Wisconsin DNR lists Musky as common on Plum Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Plum Lake’s water-quality measurements separately, and the water-quality trend over 7 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
Does Plum Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Plum Lake (clouds, ice, or an off-season gap). The most recent reading was high (619,441 cells/mL). Blue-green algae can appear and clear within days, so check Wisconsin's current advisory before swimming.
Are there boat ramps on Plum Lake?
- Plum Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Plum Lake, Plum Lake. Public access is listed as yes.
Can I fish at Plum Lake?
- Plum Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. 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.
Explore Plum Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
Fish species and the cleanest lakes across Wisconsin
Fish species and best lakes in Vilas County
Species activity outlook by water temperature and season
Top lakes and where to stay in the Northwoods Wisconsin area
Where to stay at Wisconsin's top lakes, each with its readings
Lakes in the Wisconsin River Watershed, ranked by water quality
Wisconsin's cleanest lakes, ranked on agency measurements
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Other Lakes in Wisconsin
Oligotrophic Lakes in Wisconsin
Compare Plum Lake With Nearby Lakes
Where this data comes from
77 measurements from 1 monitoring station, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX77 samples · 2020–2026
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
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