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LakeQuality

Okauchee Lake Site

B
Grade B — Good
Good · #34 of 35 lakes in the county · 4.6 ft clear · Mesotrophic · 1,210 acres
Mesotrophic

Okauchee Lake Site in Waukesha County, Wisconsin has a water quality grade of B (Good). Water clarity: 4.6 ft visibility. Phosphorus: 16.2 µg/L. Maximum depth: 90 ft. Surface area: 1210 acres.

Wisconsin DNR lists Musky as common on Okauchee Lake Site. DNR survey details →

Clarity
4.6 ft
Max depth
90 ft
Area
1,210 acres
Type
Mesotrophic
Trend
Improving
Public access
Yes

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Okauchee Lake Site is a 1,210-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 2024. Overall water quality is improving over recent sampling years. The lake supports 6 documented fish species including Musky, Panfish, and Largemouth Bass. Public access is available. Compared to the 34 other monitored lakes in Waukesha County, Okauchee Lake Site ranks #34 for water quality.

Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2024-08-28. Grade methodology: LakeQuality methodology.

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Swimming Safety

Grade only

Low 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

Compare the safest swimming lakes near Milwaukee

Get alerts for Okauchee Lake Site

Water Quality Grade: B (Good)

Murky, only visible to about 4.6 ft. Phosphorus level: 16.2 µg/L. Trophic State Index: 50.

MetricValueGrade
Water Clarity (Secchi Depth)4.6 ftNot graded
Phosphorus16.2 µg/LGood
Chlorophyll-a (Algae)No recent samples
Trophic State Index (TSI)50Mesotrophic

Moderate nutrients, good water quality

Where to stay near Okauchee Lake Site

Compare lakeside cabins, hotels, and vacation rentals near Okauchee Lake Site 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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Planning a whole trip? See where to stay at Wisconsin’s top lakes →

DNR fisheries survey

Wisconsin DNR lists Musky as common on Okauchee Lake Site.

A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Okauchee Lake Site B from EPA Water Quality Portal chemistry, and the water-quality trend over 7 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. Monitored by volunteers since 1995. 17 stations on file (most recent sample 2025).

DNR Assessment
Reported
Trophic State Index 45 (mesotrophic) · 5-year average

Fish Species (DNR-rated)

Musky(Common)Largemouth Bass(Common)Northern Pike(Common)Panfish(Present)Smallmouth Bass(Present)Walleye(Present)

Lake Details

CharacteristicValue
Maximum Depth90 ft
Surface Area1,210 acres
Public AccessYes

Fish Species

Click a species to see every graded lake where it is documented.

Fishing Okauchee Lake Site

Invasive & Introduced Species

Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.

Banded Mystery SnailChinese Mystery SnailCurly-Leaf PondweedEurasian Water-MilfoilHybrid Eurasian / Northern Water-MilfoilPurple LoosestrifeZebra MusselStarry Stonewort

Based on 7 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Improving+1.12 m/yr7
Phosphorus Stable-0.09 µg/L/yr7
Chlorophyll-a Improving-0.4 µg/L/yr2
See year-by-year chart →

EPA Impairment Status

Okauchee Lake Site is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5R).

Causes of impairment

Nutrients (phosphorus, nitrogen)

Source: EPA ATTAINS assessment unit WI10009840 · Official waterbody report · Matched by proximity (0.25 km)

County Ranking

Ranked #34 of 35 lakes in Waukesha County

Nearby Lakes With Higher Grades

Okauchee Lake Site holds Grade B. One nearby lake has a higher nutrient-and-algae grade — useful for a swim day, not a reason to skip lodging here.

See full comparison →

Nearby Lakes in Waukesha County

Frequently asked questions about Okauchee Lake Site

Where is Okauchee Lake Site?

Okauchee Lake Site 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 Okauchee Lake Site?

Okauchee Lake Site in Waukesha County, Wisconsin has a water quality grade of B (Good). Water clarity: 4.6 ft visibility. Phosphorus: 16.2 µg/L. Maximum depth: 90 ft. Surface area: 1210 acres.

Is Okauchee Lake Site safe to swim in?

Good for swimming, clear water with low algae levels. Okauchee Lake Site has a water quality grade of B (Good). Always check local health department advisories before swimming.

How deep is Okauchee Lake Site?

Okauchee Lake Site has a maximum depth of 90 feet. The lake covers 1210 acres.

What fish are in Okauchee Lake Site?

Fish species found in Okauchee Lake Site include Musky, Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Walleye. Okauchee Lake Site is located in Waukesha County, Wisconsin.

What did the DNR fisheries survey find at Okauchee Lake Site?

Wisconsin DNR lists Musky as common on Okauchee Lake Site. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Okauchee Lake Site B from EPA Water Quality Portal chemistry, and the water-quality trend over 7 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.

State Parks Near Okauchee Lake Site

Where this data comes from

19 measurements from 2 monitoring stations, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • Wisconsin Department of Natural ResourcesWIDNR_WQX19 samples · 2020–2024

Analytical methods

  • Phosphorus by Colorimetry
Monitoring station identifiers (2)

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