Pewaukee Lake, Upper Fox River - Illinois Watershed (FX07)
Pewaukee Lake, Upper Fox River - Illinois Watershed (FX07)
Pewaukee Lake (772000)
2437.22 Acres
Natural Community
Natural communities (stream and lake natural communities) represent model results that use predicted flow and temperature based on landscape features and related assumptions. Ranges of flow and temperature associated with specific aquatic life communities (fish, macroinvertebrates) help biologists identify appropriate resource management goals. Wisconsin Natural Communities.
Deep Lowland
Year Last Monitored
This is the most recent date of monitoring data stored in SWIMS. Additional surveys for fish and habitat may be available subsequent to this date.
Trout Water 
Trout Waters are represented by Class I, Class II or Class III waters. These classes have specific ecological characteristics and management actions associated with them. For more information regarding Trout Classifications, see the Fisheries Trout Class Webpages.
Outstanding or Exceptional 
Wisconsin has designated many of the state's highest quality waters as Outstanding Resource Waters (ORWs) or Exceptional Resource Waters (ERWs). Waters designated as ORW or ERW are surface waters which provide outstanding recreational opportunities, support valuable fisheries and wildlife habitat, have good water quality, and are not significantly impacted by human activities. ORW and ERW status identifies waters that the State of Wisconsin has determined warrant additional protection from the effects of pollution. These designations are intended to meet federal Clean Water Act obligations requiring Wisconsin to adopt an 'antidegradation' policy that is designed to prevent any lowering of water quality - especially in those waters having significant ecological or cultural value.
Impaired Water 
A water is polluted or 'impaired' if it does not support full use by humans, wildlife, fish and other aquatic life and it is shown that one or more of the pollutant criteria are not met.

Fish and Aquatic Life

Current Use
The use the water currently supports. This is not a designation or classification; it is based on the current condition of the water. Information in this column is not designed for, and should not be used for, regulatory purposes.
Deep Lowland
Deep lowland lake describes the depth and location of the lake in a watershed. These variables affect the lakes response to watershed variables.
Attainable Use
The use that the investigator believes the water could achieve through managing "controllable" sources. Beaver dams, hydroelectric dams, low gradient streams, and naturally occurring low flows are generally not considered controllable. The attainable use may be the same as the current use or it may be higher.
Fish and Aquatic Life - waters that do not have a specific use designation subcategory assigned but which are considered fishable, swimmable waters.
Designated Use
This is the water classification legally recognized by NR102 and NR104, Wis. Adm. Code. The classification determines water quality criteria and effluent limits. Waters obtain designated uses through classification procedures.
Default FAL
Fish and Aquatic Life - Default Waters do not have a specific use designation subcategory but are considered fishable, swimmable waters.


Pewaukee Lake, in the Upper Fox River - Illinois Watershed, is a 2,437.16 acre lake that falls in Waukesha County. This lake is managed for fishing and swimming and is currently not considered impaired.

Date  2011

Author   Aquatic Biologist

Historical Description

A large elongated lake created by moraine blocking of a preglacial erosion valley (Juday, 1914) causing impoundment and reversal of drainage. Nearly half the present acreage is the result of impoundment by an artificial dam of six-foot head on the outlet stream, Pewaukee River. The east end is very shallow and was marsh prior to impoundment. There are three small contributing streams in addition to springs supplying water. The fishery consists of northern pike, pan fish, largemouth bass and walleyes. The lake has enjoyed a reputation for excellent fishing for many years. The water is generally cloudy or turbid due to algae in suspension. Weeds and algae are major-use problems and great quantities of chemicals are applied annually for treatment. Public access is afforded by several road ends, a city park beach, and an unimproved county park area currently being developed. Well over a thousand homes border the lake, many without sewage disposal. They contribute indirectly to the fertility level and are partially the cause of vegetation problems. The lake community provides little cover for nesting waterfowl, however it is used extensively by migrating ducks as a resting area. In 1941, it was suggested that a waterfowl refuge be created on the west end.

Source: 1963, Surface Water Resources of Waukesha County Pewaukee Lake T7N, R18, 19E Surface Acres = 2,359, S.D.F. = 2.01, Maximum Depth = 45 feet.

Date  1963

Author   Surface Water Inventory Of Wisconsin

Pewaukee Lake, Upper Fox River - Illinois Watershed (FX07) Fish and Aquatic LifePewaukee Lake, Upper Fox River - Illinois Watershed (FX07) RecreationPewaukee Lake, Upper Fox River - Illinois Watershed (FX07) Fish Consumption

General Condition

Pewaukee Lake (772000) was assessed during the 2016 listing cycle; total phosphorus and chlorophyll sample data were clearly below 2016 WisCALM listing thresholds for the Recreation use and Fish and Aquatic Life use. This water is meeting these designated uses and is not considered impaired.

Date  2015

Author  Ashley Beranek


Wisconsin has over 84,000 miles of streams, 15,000 lakes and milllions of acres of wetlands. Assessing the condition of this vast amount of water is challenging. The state's water monitoring program uses a media-based, cross-program approach to analyze water condition. An updated monitoring strategy (2015-2020) is now available. Compliance with Clean Water Act fishable, swimmable standards are located in the Executive Summary of Water Condition in 2018. See also the 'monitoring and projects' tab.



Land Acquisition
The Pewaukee Lake Sanitary District (PLSD) will use this grant to pay for part of the purchase of the Ogden property, located in the Town of Pewaukee. The parcel is 56 acres, including 50 acres of wetland and 6 acres of upland.
Aquatic Invasive Species Removal
LAKE PEWAUKEE SANITARY DISTRICT: ACQ-Lake Pewaukee SD Property Acquisition
Land Acquisition
The Pewaukee Lake Sanitary District (PLSD) will use this grant to pay for the recent purchase of the Gluth property, located in the City of Pewaukee. The parcel is 30.67acres, including 26 acres of wetland and 4.67acres of upland woods and prairie. The parcel is primarily located in the shoreland zone of Pewaukee Lake.
Aquatic Invasive Species Removal
Land Acquisition
The Waukesha County Park and Planning Commission will acquire 86.6 acres of land for lake protection. The preservation of this parcel for open space and passive park use.

Management Goals

Wisconsin's Water Quality Standards provide qualitative and quantitative goals for waters that are protective of Fishable, Swimmable conditions [Learn more]. Waters that do not meet water quality standards are considered impaired and restoration actions are planned and carried out until the water is once again fishable and swimmable

Management goals can include creation or implementation of a Total Maximum Daily Load analysis, a Nine Key Element Plan, or other restoration work, education and outreach and more. If specific recommendations exist for this water, they will be displayed below online.


Monitoring the condition of a river, stream, or lake includes gathering physical, chemical, biological, and habitat data. Comprehensive studies often gather all these parameters in great detail, while lighter assessment events will involve sampling physical, chemical and biological data such as macroinvertebrates. Aquatic macroinvertebrates and fish communities integrate watershed or catchment condition, providing great insight into overall ecosystem health. Chemical and habitat parameters tell researchers more about human induced problems including contaminated runoff, point source dischargers, or habitat issues that foster or limit the potential of aquatic communities to thrive in a given area. Wisconsin's Water Monitoring Strategy was recenty updated.

Grants and Management Projects

Monitoring Projects

Watershed Characteristics

Pewaukee Lake is located in the Upper Fox River - Illinois watershed which is 151.08 miĀ². Land use in the watershed is primarily suburban (35.10%), wetland (17%) and a mix of urban (14.20%) and other uses (33.70%). This watershed has 218.00 stream miles, 2,907.45 lake acres and 12,048.42 wetland acres.

Nonpoint Source Characteristics

This watershed is ranked Not Available for runoff impacts on streams, Not Available for runoff impacts on lakes and High for runoff impacts on groundwater and therefore has an overall rank of High. This value can be used in ranking the watershed or individual waterbodies for grant funding under state and county programs.However, all waters are affected by diffuse pollutant sources regardless of initial water quality. Applications for specific runoff projects under state or county grant programs may be pursued. For more information, go to surface water program grants.

Natural Community

Pewaukee Lake is considered a Deep Lowland under the state's Natural Community Determinations.

Natural communities (stream and lake natural communities) represent model resultsand DNR staff valiation processes that confirm or update predicted conditions based on flow and temperature modeling from historic and current landscape features and related variables. Predicated flow and temperatures for waters are associated predicated fish assemblages (communities). Biologists evaluate the model results against current survey data to determine if the modeled results are corect and whether biological indicators show water quaity degradation. This analysis is a core component of the state's resource management framework. Wisconsin's Riverine Natural Communities.

Deep lowland lake describes the depth and location of the lake in a watershed. These variables affect the lakes response to watershed variables.