North Lake
North Lake in Waukesha County, Wisconsin has a water quality grade of B (Good). Water clarity: 8 ft visibility. Phosphorus: 17.9 µg/L. Maximum depth: 78.4 ft. Surface area: 440 acres.
- Clarity
- 8 ft
- Max depth
- 78.4 ft
- Area
- 440 acres
- Type
- Mesotrophic
- Trend
- ↑ Improving
Next lake in Waukesha County
North Lake is a 440-acre mesotrophic lake in Waukesha County, Wisconsin with a maximum depth of 78 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. Compared to the 34 other monitored lakes in Waukesha County, North Lake ranks #12 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-03-31. 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 8 ft. Phosphorus level: 17.9 µg/L. Trophic State Index: 46.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 8 ft | Not graded |
| Phosphorus | 17.9 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 46 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near North Lake
Compare lakeside cabins, hotels, and vacation rentals near North 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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Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 78.4 ft |
| Surface Area | 440 acres |
Fish Species
Click a species to see every graded lake where it is documented.
Fishing North 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.
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 1986. 10 stations on file (most recent sample 2025).
Fish Species (DNR-rated)
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.6 m/yr | 5 |
| Phosphorus | → Stable | +0.18 µg/L/yr | 6 |
EPA Impairment Status
North 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 WI10001324 · Official waterbody report
County Ranking
Ranked #12 of 35 lakes in Waukesha County
Nearby Lakes in Waukesha County
Frequently asked questions about North Lake
What is the water quality grade for North Lake?
- North Lake in Waukesha County, Wisconsin has a water quality grade of B (Good). Water clarity: 8 ft visibility. Phosphorus: 17.9 µg/L. Maximum depth: 78.4 ft. Surface area: 440 acres.
Is North Lake safe to swim in?
- Good for swimming, clear water with low algae levels. North Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
How deep is North Lake?
- North Lake has a maximum depth of 78.4 feet. The lake covers 440 acres.
What fish are in North Lake?
- Fish species found in North Lake include Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Walleye. North Lake is located in Waukesha County, Wisconsin.
Explore North Lake across LakeGrade
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Species activity outlook by water temperature and season
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Moderate nutrients, good water quality
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Where this data comes from
300 measurements from 8 monitoring stations, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX300 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
- Total Phosphorus After Block Digestion
Monitoring station identifiers (8)
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