Water quality data
The Bureau of Drinking Water and Groundwater developed and maintains data about Wisconsin’s drinking water and groundwater quality. Learn more about what’s in the water you drink:
Drinking Water System
The purpose of the Drinking Water System is to enforce Safe Drinking Water Act (SDWA) regulations covering Public Water Systems (PWS). The public Drinking Water System (DWS) is a data system created and maintained by the Wisconsin Department of Natural Resources, Bureau of Drinking Water and Groundwater. It contains the monitoring and reporting requirements for each Public Water System and their drinking water sampling results. It also includes violations for any missing requirements and exceedances of the maximum contaminant levels (MCLs).
Groundwater Retrieval Network
This system reports data from the department’s Public Water Supply (public drinking water supply wells), Private Water Supply (private drinking water supply wells, non-point source priority watershed projects, and special groundwater studies), and the Bureau of Waste’s Groundwater and Environmental Monitoring System (GEMS) (landfill wells). Data covers the period from the early 1970s to present for the Public Water Supply data, 1988 to present for the Private Water Supply data, and from the mid 1970s to present for the GEMS database
Drinking water and groundwater standards and health advisory levels
Includes a table of information with Wisconsin NR 140 Groundwater Enforcement Standard (ES), NR 809 Maximum Contaminant Level (MCL) or Lifetime Health Advisory Level (HAL) for contaminants that apply to drinking water or groundwater.
Source water assessment
The 1996 amendments to the Safe Drinking Water Act require that states complete source water assessments for all public drinking water systems. The primary purpose of an assessment is to determine the relative susceptibility of an area’s source water to contamination. For all assessments on this site, susceptibility is defined as the likelihood that a contaminant of concern will enter a public water supply at a level that may result in adversely impacting human health. Source water is untreated water from streams, rivers, lakes, and groundwater aquifers. A susceptibility determination is based on a stepwise synthesis of information regarding the well or surface water intake vulnerability and the source water’s sensitivity to a potential source of a contaminant of concern.