- a) A Class A community water supply means any surface water community water supply and any community water supply that includes coagulation, lime softening, ultraviolet disinfection, membrane filtration (including reverse osmosis), or sedimentation as part of its primary treatment. [415 ILCS 45/5.1]
- b) A Class B community water supply means any community water supply that includes filtration (other than membrane filtration), aeration and filtration (other than membrane filtration), or ion exchange equipment as a part of its primary treatment, and is not a Class A community water supply. [415 ILCS 45/5.1] Facilities with aeration but without filtration or ion exchange are not considered Class B facilities.
- c) A Class C community water supply means any community water supply that uses chemical feeding, and is not a Class A or Class B community water supply. [415 ILCS 45/5.1]
- d) A Class D community water supply means any community water supply that has pumpage, storage, or distribution facilities, and is not a Class A, Class B or Class C community water supply. [415 ILCS 45/5.1]
Community water supply facilities are classified as follows:
(Source: Amended at 41 Ill. Reg. 14182, effective November 13, 2017)