SOURCES OF DRINKING WATER

• Wisconsin has nearly 11,500 public water systems which meet the daily water needs of about 4 million people. Public water systems that are owned by a community are called municipal water systems. Waukesha County has 20 municipal water systems.  

GROUNDWATER PROTECTION POLICIES   

• 10 of 20 municipal water systems in Waukesha County have a wellhead protection plan: Brookfield, City of Pewaukee, Delafield, Hartland, Menomonee Falls, Mukwonago, Muskego, Oconomowoc, Pewaukee Village and Sussex.
• 7 of 20 municipal water systems in Waukesha County have a wellhead protection ordinance: Brookfield, Delafield, Hartland, Menomonee Falls, Muskego, Pewaukee Village and Sussex.
• Waukesha County has adopted an animal waste management ordinance.

MONEY SPENT ON CLEANUP

• Over $70 million has been spent on petroleum cleanup in Waukesha County from leaking underground storage tanks, which equates to $186 per county resident.
• 1 municipal water system in Waukesha County has spent money to reduce nitrate levels.

GROUNDWATER USE    

• From 1979 to 2005, total water use in Waukesha County has increased from about 28.0 million gallons per day to about 39.7 million gallons per day.*
• The increase in total water use over this period is due to increases in all use categories except aquaculture through 2000, with a decrease in industrial, irrigation and public use and losses to 2005.
• The proportion of county water use supplied by groundwater has generally been greater than 99% during the period 1979 to 2000 and decreased in 2005 to 86%.*
• Water use in Wisconsin is generally estimated for the following categories:
  • Domestic
  • Livestock
  • Aquaculture
  • Irrigation
  • Industrial
  • Commercial
  • Public use and losses
  • Thermoelectric or mining*

* Thermoelectric and mining data are not considered in water-use tables or figures on this web site. Thermoelectric-power water use is the amount of water used in the process of generating thermoelectric power. The predominant use of water is as non-contact cooling water to condense the steam created to turn the turbines and generate electricity.

SUSCEPTIBILITY OF GROUNDWATER TO CONTAMINANTS   

• Wisconsin has abundant quantities of high-quality groundwater, but once groundwater is contaminated, it's very expensive and often not technically possible to clean.
• An evaluation of the susceptibility of groundwater to contamination in Waukesha County can be seen in the FULL REPORT or accessed through the map link above.

GROUNDWATER QUALITY

• 97% of 664 private well samples collected in Waukesha County from 1990-2006 met the health-based drinking water limit for nitrate-nitrogen.  
• A 2002 study estimated that 21% of private drinking water wells in the region of Wisconsin that includes Waukesha County contained a detectable level of an herbicide or herbicide metabolite. Pesticides occur in groundwater more commonly in agricultural regions, but can occur anywhere pesticides are stored or applied.   
• There are no atrazine prohibition areas in Waukesha County.
• 90% of 61 private well samples collected in Waukesha County met the health standard for arsenic.

POTENTIAL SOURCES OF CONTAMINANTS

• There are 427 open-status sites in Waukesha County that have contaminated groundwater and/or soil. These sites include 124 Leaking Underground Storage Tank (LUST) sites, 159 Environmental Repair (ERP) sites, 132 spill sites and 12 Voluntary Party Liability Exemption (VPLE) sites.   
• There is 1 concentrated animal feeding operation in Waukesha County.
• There are 2 licensed landfills in Waukesha County.
• There are 4 Superfund sites in Waukesha County.

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