The Metropolitan Water Reclamation District of Greater Chicago's (District) Sewage and Waste Control Ordinance (Ordinance) defines a significant industrial user (SIU) as:
"…any person who: (i) is subject to categorical pretreatment standards, or (ii) discharges greater than 25,000 gallons per day of process wastewater to the sewerage system, excluding water-carried human wastes from sanitary conveniences such as toilets, wash bowls, bathtubs, showers and residential laundries, noncontact cooling water, boiler blowdown water, and uncontaminated storm water, or (iii) discharges process wastewater in excess of five percent or more of the average dry weather hydraulic or organic capacity of the receiving water reclamation facilities, or (iv) is designated by the District as having a reasonable potential for adversely affecting the operations of the water reclamation facilities or for violating any standard or requirement of this Ordinance."
The District has identified 333 SIUs under its jurisdiction. The following SIU list is current as of May 23, 2019.
