Many industries discharge to municipal Wastewater Treatment Plants (WWTP) rather than discharge directly to surface waters or groundwater. Municipal WWTPs often regulate their industrial users through an Industrial Pretreatment Program (IPP) required by their NPDES or Groundwater discharge permit. The IPPs provide the basis for WWTPs to regulate industries so industrial pollutants do not interfere with treatment processes or pass through to our lakes, and streams, and groundwater. IPPs may require industries to pretreat wastewater or otherwise reduce or eliminate harmful pollutants. The IPP is a federally mandated program and a core part of the federal Clean Water Act.

Since implementation, significant progress has been made in identifying sources of PFAS, specifically PFOS, to WWTPs and reducing levels released to the environment.