525 ILCS 45/5.3
Any person or land occupier that is responsible for a point of withdrawal classified as a high-capacity well, high-capacity intake, or public water supply shall participate in the Illinois State Water Survey's Illinois Water Inventory Program. However, high-capacity wells used for agricultural irrigation and high-capacity intakes used for agricultural irrigation are exempt from this Section for the first 5 years after the effective date of this amendatory Act of the 96th General Assembly. A person or land occupier that is responsible for a point of withdrawal classified as a high-capacity well or high-capacity intake used for irrigation for agriculture shall determine water use through estimation methods deemed acceptable by the Illinois State Water Survey. A person or land occupier that is responsible for a point of withdrawal that is classified as a high-capacity well or a high-capacity intake used for irrigation that lies within the boundaries of a water authority or other local government entity that estimates irrigation withdrawals through a method deemed acceptable by the Illinois State Water Survey is exempt from participating as an individual in the Illinois Water Inventory Program.
525 ILCS 45/5.3