Nepco Lake
Nepco Lake in Wood County, Wisconsin has a water quality grade of B (Good). Water clarity: 10.5 ft visibility. Phosphorus: 10.9 µg/L. Maximum depth: 29 ft. Surface area: 496 acres.
Wisconsin DNR lists Panfish as common on Nepco Lake. DNR survey details →
- Clarity
- 10.5 ft
- Typical in August
- 73°F
- Max depth
- 29 ft
- Area
- 496 acres
- Type
- Mesotrophic
- Trend
- → Stable
- Public access
- Yes
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Nepco Lake is a 496-acre mesotrophic lake in Wood County, Wisconsin with a maximum depth of 29 feet. Water quality is graded B based on 1 sampling years through 2026. Water clarity is declining over recent sampling years. The lake supports 6 documented fish species including Musky, Panfish, and Largemouth Bass. Public access is available with 4 public boat landings. Compared to the 2 other monitored lakes in Wood County, Nepco Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-28. Grade methodology: LakeQuality methodology.
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Swimming Safety
Grade onlyLow algae
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)
Good clarity, visible to about 10.5 ft. Phosphorus level: 10.9 µg/L. Trophic State Index: 41.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10.5 ft | Not graded |
| Phosphorus | 10.9 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 41 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Nepco Lake
Compare lakeside cabins, hotels, and vacation rentals near Nepco Lake in Wood 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 Nepco Lake
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Planning a whole trip? See where to stay at Wisconsin’s top lakes →
Water Temperature
Nepco Lake typically sits around 73°F at the surface in August. Summer average is about 74°F. Usually warmest in Jul (about 78°F) and coldest in Sep (about 69°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 16 field readings (2024–2025) via the EPA Water Quality Portal. See the full Nepco Lake water temperature breakdown →
Wisconsin DNR lists Panfish as common on Nepco Lake.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Nepco Lake B from EPA Water Quality Portal chemistry, and the water-quality trend over 5 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 2013. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 29 ft |
| Surface Area | 496 acres |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Nepco Lake County ParkPublic
- Ben Hanson ParkPublic
- Wisconsin River DrivePublic
- Riverside ParkSemi-private
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 Nepco 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 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.625 m/yr | 5 |
| Phosphorus | ↑ Improving | -1.75 µg/L/yr | 3 |
Reservoir Info (USACE NID)
Nepco Lake is a man-made reservoir impounded by the Four Mile Creek (completed 1926), built primarily for water supply on the FOURMILE CREEK & BLOODY RUN; gravity-type dam, 33 ft tall and 2,084 ft long.
- Surface area
- 494 ac
- Normal storage
- 4,748 ac-ft
- Max storage
- 6,000 ac-ft
- Drainage area
- 29 sq mi
- Hazard class
- Low
- Owner
- Domtar Wisconsin Dam Corp.
All listed purposes: Water Supply;Recreation;Hydroelectric.
Source: USACE National Inventory of Dams, NID ID WI00032 · Operator website
Regulated Pollution Sources Nearby
6 EPA-permitted facilities operate within about 5 miles of Nepco Lake under Clean Water Act (NPDES) discharge permits, including 3 classified by the EPA as major dischargers. 6 facilities have a reported Clean Water Act violation in the past three years.
- Wisconsin Rapids City WwtfWisconsin Rapids · 2.2 mi away · NPDES WI0025844MajorRecent violation
- Erco Worldwide (Usa) Inc - Port EdwardsPort Edwards · 2.4 mi away · NPDES WI0003565MajorRecent violation
- Domtar - NekoosaNekoosa · 3.4 mi away · NPDES WI0003620MajorRecent violation
- Port Edwards Wastewater Treatment FacilityPort Edwards · 0.8 mi away · NPDES WI0020451Recent violation
- Vesper Wastewater Treatment FacilityVesper · 1.8 mi away · NPDES WI0030309Recent violation
- Nekoosa Wastewater Treatment FacilityNekoosa · 4.6 mi away · NPDES WI0020613Recent violation
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
County Ranking
Ranked #1 of 3 lakes in Wood County
Nearby Lakes in Wood County
Frequently asked questions about Nepco Lake
Where is Nepco Lake?
- Nepco Lake is a lake in Wood County, Wisconsin. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Nepco Lake?
- Nepco Lake in Wood County, Wisconsin has a water quality grade of B (Good). Water clarity: 10.5 ft visibility. Phosphorus: 10.9 µg/L. Maximum depth: 29 ft. Surface area: 496 acres.
Is Nepco Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Nepco Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
What is the water temperature of Nepco Lake?
- Nepco Lake typically sits around 73°F at the surface in August, from 16 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.
How deep is Nepco Lake?
- Nepco Lake has a maximum depth of 29 feet. The lake covers 496 acres.
What fish are in Nepco Lake?
- Fish species found in Nepco Lake include Musky, Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Walleye. Nepco Lake is located in Wood County, Wisconsin.
What did the DNR fisheries survey find at Nepco Lake?
- Wisconsin DNR lists Panfish as common on Nepco Lake. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Nepco Lake B from EPA Water Quality Portal chemistry, and the water-quality trend over 5 years of monitoring is stable. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Nepco Lake?
- Nepco Lake has 4 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Nepco Lake County Park, Ben Hanson Park, Wisconsin River Drive, Riverside Park. Public access is listed as yes.
Explore Nepco Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
Fish species and top-graded lakes across Wisconsin
Fish species and best lakes in Wood County
Species activity outlook by water temperature and season
Where to stay at Wisconsin's top lakes, each with its grade
Lakes in the Wisconsin River Watershed, ranked by water quality
Moderate nutrients, good water quality
Wisconsin's cleanest and most-polluted lakes, ranked
More Wisconsin Lake Rankings
State Parks Near Nepco Lake
Other Grade B Lakes in Wisconsin
Mesotrophic Lakes in Wisconsin
Where this data comes from
37 measurements from 1 monitoring station, 2022–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX37 samples · 2022–2026
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
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