BACOG Water Resources Initiative 

Nearly all of the BACOG area’s water comes from the same shared shallow aquifer system.  This is true whether households and businesses get their water from a private well in the yard or through a municipal distribution system.  It’s all groundwater coming from the same shared aquifers.  

BACOG has been working to determine the quantity, quality, vulnerability, and sustainability of our areas water supply since 2001. BACOG’s mapping, monitoring, and testing programs provide vital information to help our region ensure there is sufficient amount of water to support the population and development in and around our region and protect it from contamination.   

The Water Resources Initiative consists of three major components: 1. Aquifer Water Level Monitoring; 2. Water Quality Well Network; and 3. Private Well Water Testing.   

Aquifer Water Levels Monitoring Program  

BACOG measures water levels in the shallow aquifer system each year and coordinates a comprehensive assessment of the data for each five-year period.  The resulting trend information about water quantity in our region will be critical to helping BACOG governments respond with any necessary actions to protect our primary water source.  Annual measurements are taken at:  

  • 14 monitoring wells throughout the BACOG area that are measured by hand – with services donated from the U.S. Geological Survey (USGS) and Illinois State Water Survey (ISWS).  
  • 3 USGS transducer-equipped monitoring wells at the Villages of South Barrington, Deer Park and Lake Barrington.  
  • 5 stream gages in Flint Creek – data downloaded in the field by BACOG staff  
  • 65 public wells in 14 municipalities in and adjacent to the BACOG area.   

BACOG also contracts with USGS for continuous water level monitoring at 3 well sites in the BACOG area. These transducer-equipped monitoring wells provide real-time access to water level information 365 days per year via the BACOG / USGS websites.  

See below for more details.

The Water Quality Well Network Program

The Water Quality Well Network Program, established in 2019, consists of a network of semi-public wells throughout the BACOG area where well water can be tested on a regular basis, with the goal of establishing the water quality in the area’s shallow aquifer system and identifying changes over time.   Wells are on properties where there is little potential for turnover in ownership and access for testing will be available year after year.  Examples include:  cemeteries, parks, conservation areas, schools, fire districts, community centers with a well.  

BACOG government members have each committed to a once-a-year water sampling of wells in their community that are part of the BACOG network.  The first year of testing in each network well established the baseline water quality in that community’s wells.   Repeat testing of the same wells on an annual, or once every two years basis, will demonstrate changes, if any, in water quality parameters over the long term and inform important local government decision-making.    

Private Well Water Quality Testing

In partnership with the Lake County Health Department and Barrington Area Library, BACOG hosts an annual Private Well Water Testing Event to help residents with private wells test their well water for bacteria and nitrates.     

In 2022, over 320 water samples from BACOG area homes were collected.  Water testing found no evidence of elevated nitrate levels in any samples, less than 13% of the samples returned positive results for coliform bacteria, and less than 1% returned positive results for e.coli.   

The 2023 event will be held on October 11th at the site our of Community Partner, the Barrington Area Library. 


Continuous Water Level Monitoring

Click here for REAL-TIME data from BACOG’s three wells in Deer Park, Lake Barrington and South Barrington.

Click here for REAL-TIME data from wells in Illinois


Science & Methodology

The methodology for the science portion of the BACOG groundwater resources initiative defined the processing and classification of well log descriptions into simplified units of bedrock, aquifer, aquitard, and aquiclude. These procedures are described in detail in the reports and articles under the “Educate / Resources” tab.

Well Classification

The science portion has been heavily advised by Dr. Kurt O. Thomsen,Ph.D., P.G., a professional hydrogeologist with many years of experience in hydrological and environmental consulting. His work with BACOG’s groundwater has been invaluable to this project. The science and methodology have also been reviewed and advised by various other academic and State and U.S. governmental sources.

A Rapid Method for Analyzing Well Log Records in Preparation for Water Resource Mapping


GIS: Mapping and Visualization

GIS, or a Geographic Information System, is used to create the layer maps for the 3 dimensional stratigraphic model as well as other important maps that define the shallow aquifer system.

Aquifer Diagram

BACOG has used GIS in many ways and it has been an integral part of analyzing the groundwater resources and communicating that information to officials and community members. Creating the model has allowed BACOG to apply and query information from this data for applications at local and regional scales.

Online video shows the representative model produced using GIS software.

Depth to Bedrock

In the BACOG area, the shallow aquifer system is composed of unconsolidated glacial soil materials and the shallow dolomite bedrock. The unconsolidated soils, including gravel, sand, clay and other sediments, contain underground pockets of water that supply water to the vast majority of BACOG-area wells. Bedrock is a unit of consolidated rock that lies beneath the glacial soils. Bedrock is also considered aquifer because it contains fractures, cracks, and void spaces that contain and transmit water. Though less common, a number of wells in the area are drilled into the upper portion of this bedrock unit.

Depth to bedrock is the distance from the ground surface to the top of the shallow bedrock unit.

BACOG Groundwater Recharge Areas

Recharge characteristics were mapped in the BACOG area from the research undertaken in the water resource initiative. Recharge is the process by which rain, snow melt and stormwater move downward from the surface to groundwater aquifers. Recharge is the primary method through which water enters an aquifer.

BACOG analyzed the soil materials from ground surface down to the first aquifer encountered to establish hydro-conductivity, that is, the relative time of travel of water through the soils. Hydro-conductivity was used to classify area recharge characteristics as highly sensitive, sensitive, moderately sensitive, poor, or very poor.

In the highly sensitive areas, the travel times of water are measured in days. In sensitive areas, recharge times range from days to several years. Poor to very poor recharge areas exhibit travel times from 40+ years to hundreds of years or more.

Click Here for Legend Recharge Descriptions

Identification of Groundwater Recharge Areas Using Readily Available Data