Significant Industrial User (SIU) Program

The City of Sioux Falls Industrial Pretreatment Program (IPP) issues permits, performs inspections, and conducts sampling of local industrial facilities classified as Significant Industrial Users (SIUs). A SIU is defined by the US Environmental Protection Agency (EPA) as an industrial user that discharges process wastewater into a publicly owned treatment works (POTW) and meets at least one of the following:

  • All industrial users subject to Categorical Pretreatment Standards under the Code of Federal Regulations - Title 40 (40 CFR) Part 403.6, and CFR Title 40 Chapter I, Subchapter N- Effluent Guidelines and Standards; and
  • Any other industrial user that:
    • discharges an average of 25,000 gallons per day or more of process wastewater to the POTW (excluding sanitary, non-contact cooling and boiler blowdown wastewater); or
    • contributes a process wastestream which makes up 5 percent or more of any design capacity of the POTW treatment plant; or
    • is designated by the City of Sioux Falls on the basis that the industrial user has a reasonable potential to adversely affect the POTW's operation.

For any questions related to the SIU Program contact the Environmental Division at 605-367-8276.

SIU Program forms & other documents