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. Rock County has 9 municipal water systems.  

GROUNDWATER PROTECTION POLICIES   

• 6 of 9 municipal water systems in Rock County have a wellhead protection plan: Clinton, Evansville, Footville, Janesville, Milton, and Orfordville.
• 2 of 9 municipal water systems in Rock County have a wellhead protection ordinance: Evansville and Janesville.
• Rock County has adopted an animal waste management ordinance.

MONEY SPENT ON CLEANUP

• Over $24 million has been spent on petroleum cleanup in Rock County from leaking underground storage tanks, which equates to $156 per county resident.
• 4 municipal water systems in Rock County have spent money to reduce nitrate levels.

GROUNDWATER USE    

• From 1979 to 2005, total water use in Rock County has increased from about 27.2 million gallons per day to about 45.4 million gallons per day.*
• The increase in total water use over this period is due to increases in domestic and irrigation uses.
• The proportion of county water use supplied by groundwater increased from about 92% to over 99% during the period 1979 to 2005.*
• 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 Rock County can be seen in the FULL REPORT or accessed through the map link above.

GROUNDWATER QUALITY

• 75% of 482 private well samples collected in Rock County from 1990-2006 met the health-based drinking water limit for nitrate-nitrogen.  
• A 2002 study estimated that 62% of private drinking water wells in the region of Wisconsin that includes Rock 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.   
• 18,941 acres of land in Rock County are in atrazine prohibition areas.
• 100% of 18 private well samples collected in Rock County met the health standard for arsenic.

POTENTIAL SOURCES OF CONTAMINANTS

• There are 85 open-status sites in Rock County that have contaminated groundwater and/or soil. These sites include 34 Leaking Underground Storage Tank (LUST) sites, 47 Environmental Repair (ERP) sites, 3 spill sites and 1 Voluntary Party Liability Exemption (VPLE) site.  
• There are 2 concentrated animal feeding operations in Rock County.
• There are 3 licensed landfills in Rock County.
• There are 2 Superfund sites in Rock County.

return to top