Illinois
Underground Injection Control (UIC)
Underground Injection Control (UIC) is a federal program set up under the Safe Drinking Water Act of 1974 to keep injection wells from contaminating groundwater. Illinois EPA's UIC page describes injection wells as wells that put fluids underground for disposal, built anywhere from elaborate designs monitored around the clock to a simple hole in the ground to take runoff. The program sorts them into five classes.
In a Phase I ESA
ASTM E1527-21 does not name injection well records among its standard record sources. Of the five classes, the shallow Class V wells are the most numerous: Illinois EPA counts over 6000 in Illinois.
| Class | What Illinois EPA's page says about it in Illinois |
|---|---|
| Class I | Deep wells that put waste, hazardous or not, beneath the deepest underground source of drinking water. The page says four are presently operating in Illinois. |
| Class II | Wells for fluids from producing and storing oil and natural gas. The page says the Illinois Department of Natural Resources, Office of Mines and Minerals, runs this class in Illinois. |
| Class III | Wells that inject fluids into an ore body to extract minerals. The page says none exist in Illinois. |
| Class IV | Wells that inject hazardous waste into or above an underground source of drinking water. Banned by regulation. |
| Class V | Shallow wells that inject non-hazardous waste into or above an underground source of drinking water. The page calls this the largest class, with over 6000 in Illinois. |
A Class V well needs no permit before it starts. It is authorized by rule, and before injection begins the Inventory Information must be submitted, on a form Illinois EPA posts, saying what kind of Class V well it is and what is injected. Once that is reviewed, the owner may have to show with more information that the well will not contaminate a drinking water source, and in rare cases may be required to get a permit. For a property with a Class V well, ask whether the inventory was submitted, and ask for it. The page, last modified July 7, 2025, does not date its counts.
This handbook does not read the Department of Natural Resources' pages.
Where to look a site up
- The pages read give no search or list of injection wells.
- Illinois EPA's UIC page links Underground Injection Well Forms, which this handbook did not open.
- The UIC page gives no program contact and does not say which bureau runs the program; its footer gives Illinois EPA's general line, (217) 782-3397. Illinois EPA's Contact page gives the Bureau of Water's line as (217) 782-9720.
Getting the file
Illinois EPA takes requests under the Illinois Freedom of Information Act through its online FOIA Request Web Form, which needs an account, or by fax, U.S. mail or special carrier. Give the facility name, address and any ID number you have. Fees, reply times and the options for large files are on the FOIA requests page.
Sources
Illinois Environmental Protection Agency pages, read October 13, 2026:
- Underground Injection Control, last modified July 7, 2025.
- Contact the Illinois EPA, last modified March 30, 2026.
- Freedom of Information Act, last modified May 2, 2024.