Nagawicka Lake
Nagawicka Lake in Waukesha County, Wisconsin has a water quality grade of B (Good). Water clarity: 9.5 ft visibility. Phosphorus: 13.5 µg/L. Maximum depth: 90 ft. Surface area: 981 acres.
Wisconsin DNR lists Largemouth Bass as common on Nagawicka Lake. DNR survey details →
- Clarity
- 9.5 ft
- Max depth
- 90 ft
- Area
- 981 acres
- Type
- Mesotrophic
- Trend
- ↑ Improving
- Public access
- Yes
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Nagawicka Lake is a 981-acre mesotrophic lake in Waukesha County, Wisconsin with a maximum depth of 90 feet. Water quality is graded B based on 1 sampling years through 2026. Overall water quality is improving over recent sampling years. The lake supports 5 documented fish species including Panfish, Largemouth Bass, and Smallmouth Bass. Public access is available with 2 public boat landings. Compared to the 34 other monitored lakes in Waukesha County, Nagawicka Lake ranks #29 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-04-29. Grade methodology: LakeGrade 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)
Moderate clarity, visible to about 9.5 ft. Phosphorus level: 13.5 µg/L. Trophic State Index: 43.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 9.5 ft | Not graded |
| Phosphorus | 13.5 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 43 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Nagawicka Lake
Compare lakeside cabins, hotels, and vacation rentals near Nagawicka Lake in Waukesha 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.
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Wisconsin DNR lists Largemouth Bass as common on Nagawicka Lake.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Nagawicka Lake B from EPA Water Quality Portal chemistry, and the water-quality trend over 6 years of monitoring is improving. 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. 7 stations on file (most recent sample 2025).
Fish Species (DNR-rated)
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 90 ft |
| Surface Area | 981 acres |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Pewaukee LakePublic
- Nagawicka LakePublic
Named access points from the USGS National Boat Ramps inventory, snapped within 5 km. More lakes with boat ramps
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Nagawicka 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: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +1.016 m/yr | 6 |
| Phosphorus | → Stable | -0.07 µg/L/yr | 5 |
Reservoir Info (USACE NID)
Nagawicka Lake is a man-made reservoir impounded by the Delafield Fish Hatchery (completed 1936), built primarily for other on the BARK; gravity-type dam, 10 ft tall and 140 ft long.
- Surface area
- 917 ac
- Normal storage
- 6,000 ac-ft
- Max storage
- 917 ac-ft
- Drainage area
- 46 sq mi
- Hazard class
- Low
- Owner
- CITY OF DELAFIELD
All listed purposes: Other;Recreation.
Source: USACE National Inventory of Dams, NID ID WI00683 · Operator website
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Nagawicka Lake under Clean Water Act (NPDES) discharge permits.
- Medline Industries, Inc.Hartland, Village Of · 1.5 mi away · NPDES WI0065943
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 #29 of 35 lakes in Waukesha County
Nearby Lakes in Waukesha County
Frequently asked questions about Nagawicka Lake
Where is Nagawicka Lake?
- Nagawicka Lake is a lake in Waukesha County, Wisconsin. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Nagawicka Lake?
- Nagawicka Lake in Waukesha County, Wisconsin has a water quality grade of B (Good). Water clarity: 9.5 ft visibility. Phosphorus: 13.5 µg/L. Maximum depth: 90 ft. Surface area: 981 acres.
Is Nagawicka Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Nagawicka Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
How deep is Nagawicka Lake?
- Nagawicka Lake has a maximum depth of 90 feet. The lake covers 981 acres.
What fish are in Nagawicka Lake?
- Fish species found in Nagawicka Lake include Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Walleye. Nagawicka Lake is located in Waukesha County, Wisconsin.
What did the DNR fisheries survey find at Nagawicka Lake?
- Wisconsin DNR lists Largemouth Bass as common on Nagawicka Lake. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Nagawicka Lake B from EPA Water Quality Portal chemistry, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Nagawicka Lake?
- Nagawicka Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Pewaukee Lake, Nagawicka Lake. Public access is listed as yes.
Explore Nagawicka Lake across LakeGrade
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Moderate nutrients, good water quality
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Where this data comes from
46 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_WQX46 samples · 2020–2026
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