Trego Lake
Trego Lake in Washburn County, Wisconsin is not rated for water quality — its monitoring record does not meet the evidence bar. Maximum depth: 36 ft. Surface area: 383 acres.
Wisconsin DNR rates Panfish as abundant on Trego Lake. DNR survey details →
- Max depth
- 36 ft
- Area
- 383 acres
- Public access
- Yes
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Why Trego Lake has no grade
We grade a lake only when the monitoring record supports a letter: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Trego Lake, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by WI DNR and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Trego Lake is a 383-acre lake in Washburn County, Wisconsin with a maximum depth of 36 feet. The lake supports 7 documented fish species including Musky, Panfish, and Largemouth Bass. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-05-06. Grade methodology: LakeQuality methodology.
Watch Trego Lake water quality
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Trego Lake
These readings exist but are not enough for an A–F grade — see why.
No clarity data.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples |
Where to stay near Trego Lake
Compare lakeside cabins, hotels, and vacation rentals near Trego Lake in Washburn 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 Trego Lake
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Planning a whole trip? See where to stay at Wisconsin’s top lakes →
Wisconsin DNR rates Panfish as abundant on Trego Lake.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality does not assign an A–F grade on Trego Lake — official chemistry is on file, not a letter. 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 2025).
Fish Species (DNR-rated)
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 36 ft |
| Surface Area | 383 acres |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Trego - NorthPublic
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 Trego 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.
Reservoir Info (USACE NID)
Trego Lake is a man-made reservoir impounded by the Trego (completed 1927), built primarily for hydroelectric on the Namekagon River; gravity-type dam, 39 ft tall and 625 ft long.
- Surface area
- 470 ac
- Normal storage
- 4,700 ac-ft
- Max storage
- 4,700 ac-ft
- Drainage area
- 488 sq mi
- Hazard class
- Significant
- Owner
- Northern States Power Co
All listed purposes: Hydroelectric;Recreation.
Source: USACE National Inventory of Dams, NID ID WI00812 · Operator website
EPA Impairment Status
Trego Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5R).
Causes of impairment
Source: EPA ATTAINS assessment unit WI10005676 · Official waterbody report
Graded lakes near Trego Lake
Trego Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Washburn County
Frequently asked questions about Trego Lake
Where is Trego Lake?
- Trego Lake is a lake in Washburn County, Wisconsin. LakeQuality has not rated this lake (UNRATED) — there is not enough recent sampling to assign a letter.
What is the water quality grade for Trego Lake?
- Trego Lake in Washburn County, Wisconsin is not rated for water quality — its monitoring record does not meet the evidence bar. Maximum depth: 36 ft. Surface area: 383 acres.
Is Trego Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Trego Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
How deep is Trego Lake?
- Trego Lake has a maximum depth of 36 feet. The lake covers 383 acres.
What fish are in Trego Lake?
- Fish species found in Trego Lake include Musky, Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Walleye, Sturgeon. Trego Lake is located in Washburn County, Wisconsin.
What did the DNR fisheries survey find at Trego Lake?
- Wisconsin DNR rates Panfish as abundant on Trego Lake. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality does not assign an A–F grade on Trego Lake — official chemistry is on file, not a letter. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Trego Lake?
- Trego Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Trego - North. Public access is listed as yes.
Explore Trego Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
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Species activity outlook by water temperature and season
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Where this data comes from
5 measurements from 1 monitoring station, 2024–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX5 samples · 2024–2026
Analytical methods
- Total Phosphorus After Block Digestion
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