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. Jefferson County has 7 municipal water systems.  

GROUNDWATER PROTECTION POLICIES   

• 5 of 7 municipal water systems in Jefferson County have a wellhead protection plan: Jefferson, Johnson Creek, Lake Mills, Waterloo and Watertown.
• 3 of 7 municipal water systems in Jefferson County have a wellhead protection ordinance: Johnson Creek, Lake Mills and Watertown.
• Jefferson County has adopted an animal waste management ordinance.

MONEY SPENT ON CLEANUP

• Over $23 million has been spent on petroleum cleanup in Jefferson County from leaking underground storage tanks, which equates to $295 per county resident.
• No municipal water systems in Jefferson County have spent money to reduce nitrate levels.

GROUNDWATER USE    

• From 1979 to 2005, total water use in Jefferson County has increased from about 16.0 million gallons per day to 28.1 million gallons per day.*
• The increase in total water use is due to increases in all categories, but most notably aquaculture and irrigation uses.
• The proportion of county water use supplied by groundwater has been consistently about 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 Jefferson County can be seen in the FULL REPORT or accessed through the map link above.

GROUNDWATER QUALITY

• 93% of 613 private well samples collected in Jefferson 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 Jefferson 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 Jefferson County.
• 89% of 19 private well samples collected in Jefferson County met the health standard for arsenic.

POTENTIAL SOURCES OF CONTAMINANTS

• There are 70 open-status sites in Jefferson County that have contaminated groundwater and/or soil. These sites include 44 Leaking Underground Storage Tank (LUST) sites, 22 Environmental Repair (ERP) sites, 2 spill sites and 2 Voluntary Party Liability Exemption (VPLE) sites.  
• There are 7 concentrated animal feeding operations in Jefferson County.
• There is 1 licensed landfill in Jefferson County.
• There are no Superfund sites in Jefferson County.

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