The Pretreatment Regulations apply to publicly owned treatment works (POTWs) and to industrial users discharging pollutants to POTWs from non-domestic sources. The Pretreatment Regulations prohibit any discharge to a POTW that causes a violation of the POTW?s NPDES permit or disrupts the POTW?s treatment process. With limited exceptions, POTWs that receive industrial waste are required to develop pretreatment programs. These programs must include mechanisms to ensure that industrial users comply with pretreatment standards and requirements, which include enforcement if necessary. The City of Fargo's (City) POTW has an approved pretreatment program and is considered a control authority with regard to the Pretreatment Regulations in their service area. EPA and North Dakota Department of Health (NDDH) inspectors conducted a pretreatment compliance inspection (PCI) at the Fargo POTW on September 12-14, 2016. Violations observed included a failure by the City to update its pretreatment ordinance, failure to implement its procedure for identifying and locating industrial users (IUs) discharging pollutants to the City?s publicly owned treatment works, failure to include all required elements in significant industrial user (SIU) permits, failure to evaluate the need for SIUs to develop slug control plans, failure to meet sampling and analysis requirements, failure to maintain records, failure to ensure that IUs complied with reporting requirements, failure to follow the City?s enforc