Ocauchee Lake
Waukesha County, Wisconsin1,210 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Ocauchee Lake. Here is what has been measured.
- Mesotrophic
- Impaired · Nutrients (phosphorus, nitrogen)
- 3 aquatic invasives
- 90 ft max depth
- Public access
- Limited data
Ocauchee Lake in Waukesha County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 6.6 ft visibility. Phosphorus: 17.5 µg/L. Maximum depth: 90 ft. Surface area: 1210 acres.
Wisconsin DNR lists Musky as common on Ocauchee Lake. DNR survey details →
Ocauchee Lake is a 1,210-acre mesotrophic lake in Waukesha County, Wisconsin with a maximum depth of 90 feet. 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, Ocauchee Lake ranks #33 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2024-08-28. Methodology: how these readings are compared.
What Ocauchee Lake is good for
From access and monitoring records, not editorial picks.
- Fishing6 species recorded
- Deep water90 ft surveyed max depth
- Big water1,210 acres
Swimming conditions
Readings onlyRecreation use not supported
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Ocauchee Lake is listed impaired under Clean Water Act §303(d) (IR 5R) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Ocauchee Lake is safe to swim in today is a call for the Wisconsin Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Ocauchee Lake
These are the measurements Wisconsin DNR publishes for Ocauchee Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 6.6 ft. Phosphorus 17.5 µg/L. TSI 48.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 6.6ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 17.5µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 48 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Ocauchee Lake
Answers come straight from the public measurements and survey records on this page.
Wisconsin DNR lists Musky as common on Ocauchee Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Ocauchee Lake’s water-quality measurements separately, 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).
Fish Species (DNR-rated)
Lake Details
Max depth
90 ft
Surface area
1,210 acres
Public access
Yes
Listed by Wisconsin DNR
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Fish Species
Click a species to see every lake where it is documented.
Fishing Ocauchee 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 7 years of monitoring (2020–2026).
Water clarity
Improving7 years
Phosphorus
Stable+0.09 µg/L/yr7 years
Chlorophyll-a
Improving-0.61 µg/L/yr4 years
EPA Impairment Status
Ocauchee Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5R).
Causes of impairment
Designated uses not supporting: Aquatic life, Recreation.
Source: EPA ATTAINS assessment unit WI10009840 · Official waterbody report
Nearby Lakes in Waukesha County
Frequently asked questions about Ocauchee Lake
Where is Ocauchee Lake?
- Ocauchee Lake is a lake in Waukesha County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Ocauchee Lake?
- Ocauchee Lake in Waukesha County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 6.6 ft visibility. Phosphorus: 17.5 µg/L. Maximum depth: 90 ft. Surface area: 1210 acres.
Is Ocauchee Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Ocauchee Lake is listed impaired under Clean Water Act §303(d) (IR 5R) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
How deep is Ocauchee Lake?
- Ocauchee Lake has a maximum depth of 90 feet. The lake covers 1210 acres.
What fish are in Ocauchee Lake?
- Fish species found in Ocauchee Lake include Musky, Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Walleye. Ocauchee Lake is located in Waukesha County, Wisconsin.
What did the DNR fisheries survey find at Ocauchee Lake?
- Wisconsin DNR lists Musky as common on Ocauchee Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Ocauchee Lake’s water-quality measurements separately, 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.
Can I fish at Ocauchee Lake?
- Public access to Ocauchee Lake is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by Wisconsin's fish and wildlife agency, so check its current regulations before you go.
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Where this data comes from
6 measurements from 1 monitoring station, 2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX6 samples · 2024
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Fish and recreation data from Wisconsin DNR Lakes