Frequently Asked Questions
Here are some of the Illinois Water Inventory Program’s most common questions. If you cannot find the information you’re looking for here or on IWIP’s other pages, please contact the IWIP team.
Yes. As of January 1, 2010, facilities with high-capacity wells or surface water intakes are required by Public Act 096-0222 to report water use each year. A high-capacity system includes any single source — or group of sources — that can pump 70 gallons per minute or more.
Agricultural irrigation was exempt for the first five years, but annual reporting became mandatory for irrigators on January 1, 2015. If you kept good water use records before that date, you are encouraged to submit them as reference points. These early records can help serve as benchmarks for estimating irrigation use across the state.
Public water systems in our database have an extra “9” in the fourth digit of the facility number. It is just a way for us to flag those systems internally — your actual EPA number has not changed.
The SIC code — or Standard Industrial Classification — is a four-digit number used to describe what your facility does. We use these codes to help organize water use data by category. For example, public water systems are classified under 4941, while electric utilities are categorized as 4911.
The contact person should be the staff member most familiar with your facility’s water use. This person may be different from the administrator or manager who receives the form. IWIP staff will reach out to this person if we have questions about your data.
Wells and surface water intakes are listed separately, with each list beginning its numbering at “1.” Surface water intakes do not have a depth and are usually labeled by name or with the word “Intake.”
Yes. IWIP tracks both self-supplied and purchased water. If you buy water but do not pump it yourself, you still need to complete the relevant sections of the form. You can simply leave the first part blank and continue with the remainder of the form.
Withdrawn water is raw water from your own wells or surface water sources that is delivered directly to your treatment plant. Purchased water is what you buy from another system. The form asks for both, with raw water withdrawals on the first page and distribution of treated water on the second.
That information is usually handled by the billing department. They should be able to give you figures on population within and outside city limits, service types, and usage amounts.
If your sources are used evenly, divide the total volume by the number of active wells or intakes. If you know the percentage output from the sources, take the percentage of the total amount and report the result in gallons.