Illinois Water Inventory Program, Illinois State Water Survey

Illinois Water Inventory Program

The Illinois Water Inventory Program (IWIP), a comprehensive program to inventory water use throughout the state, began in 1978. It is designed to collect data in three major categories: water withdrawal, water use, and water returns. For each water-using facility inventoried, the database includes locations and amounts of water withdrawn from surface water and groundwater sources, as well as significant amounts of water purchased from other facilities. Public water supplies, self-supplied industries, irrigation, fish and wildlife, and conservation uses are inventoried. Data can be summarized geographically by county, township, and drainage basin, as well as by various water use and water source categories for inclusion in publications of the USGS National Water Use Program. Annual submission of the Illinois Water Inventory form is mandatory according to Public Act 096-0222 (viewable online at

Water Irrigation Reporting Information is now available online. The site contains an irrigation handbook including forms and provides guidance on what an irrigator needs to do now and during the year for recordkeeping, calculating, and reporting irrigation water use for the 2015 growing season.

Data Uses

Current uses of the data collected through the IWIP program include:

Determination of community water supply usage

Examination of groundwater level observations and groundwater withdrawals (for example, comparisons of potentiometric surface maps of the Cambrian-Ordovician aquifer system and pumpage from that aquifer system)

Water use projections

Comparisons of aquifer withdrawals to estimated aquifer recharge (use-to-yield mapping). See An Analysis of Groundwater Use to Aquifer Potential Yield in Illinois

Regional groundwater modeling, such as performed for Kane County. See Water Resources Investigations for Kane County, Illinois

Determination of groundwater use for the U.S. Army Corps of Engineers Lake Michigan Diversion Accounting Program

Environmental impacts (for example, the impact of a toxic spill on aquifers or surface water)

Impact of high-capacity wells on neighboring wells

Publication in map form on the Arc/IMS portion of the Illinois Environmental Protection Agency's Source Water Assessment Program (SWAP) website. (Access to the mapping tool requires registration as a secure user)

Commercial-Industrial information is kept confidential: While the amount of water withdrawn by public wells and intakes is public information, the amount of water used by commercial and industrial facilities is not. Commercial-industrial pumpage, whether from wells or surface water intakes, is kept confidential unless the facility grants a specific release of the data. Commercial-industrial data is otherwise published only in combination with township or regional totals.

Data Collection

Every year, typically in January or February, a questionnaire about facilities' use of water during the previous calendar year is sent to all participating facilities, with the exception of water systems that have a Lake Michigan allocation (these systems use a different reporting period, the previous federal water year, which runs from October 1 through September 30). Facilities are given approximately twelve weeks to complete and return the form in a postage-paid return envelope. Public water systems and Industrial-Commercial facilities may also request an electronic form (see “Completing the Water Inventory Form Electronically,” below). The data are entered into the database as the completed forms are received. A second questionnaire is sent later in the year to facilities that did not respond to the first questionnaire. The IWIP staff work year-round to gather information from participants in order to resolve questions and fill data gaps for specific years.

Lake Michigan Ordinance (LMO-2 Recipients): Facilities that have a Lake Michigan allocation are required to submit a form (the LMO-2) to the Department of Natural Resources’ Office of Water Resources in Chicago. These facilities report water use on the previous federal water year, which runs from October 1 through September 30. A Water Inventory form is also sent to these facilities at approximately the same time, in October or November of the new water year.

Completing the Water Inventory Form

The paper copy of the inventory form is typically filled out by hand or with a typewriter. However, forms for certain types of Water Inventory recipients (Public Water Systems and Industrial-Commercial facilities) can be completed electronically and returned to the State Water Survey via e-mail.

Completing the Water Inventory Form Electronically

Fillable PDF: Email to request a fillable PDF of your Water Inventory form. The form and instructions for using the Typewriter tool will be sent to you. Be sure to identify your system by name and/or number in your e-mail subject line.

Steps in Completing the Water Inventory Form

A guide is available for completing your inventory form. Please refer to the explanation of terms when completing the uppermost part of the first page of the IWIP form.

The following links display sample pages for a Public Water Supply form and describe the questions in detail. Pages 1 and 3 are similar for all types of facilities, but please see How to Fill Out the Water Use Part of the Inventory Form for specific directions on filling out page 2.

    Wells and Surface Water Intakes   (Detailed Description)

    Purchased and Self-Supplied Water Use   (Detailed Description)

    Well Treatment, Water Levels, Conservation, and Discharge    (Detailed Description)

Frequently Asked Questions

If you are unsure about some part of the form or do not know how to determine the amount of water your facility purchases or withdraws, please do not hesitate to call the IWIP office at 217-333-0239 or send an e-mail ( Office hours are 8-12 and 1-5:00, Monday through Friday.

Mailing Address:

Illinois Water Inventory Program
Illinois State Water Survey
2204 Griffith Drive
Room 407A
Champaign, IL 61820-7463

Phone: 217-333-0239
Fax:     217-244-0777

Illinois State Water Survey

2204 Griffith Dr
Champaign, IL 61820-7463

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