Reducing Pollutants in Industrial Stormwater Runoff: Improved Water Quality Protection Using Prioritized Facility Regulation

Stormwater pollutants originating from industrial facilities can lead to degraded water quality, even in residentially dominated regions of the country. The National Pollutant Discharge Elimination System permit program regulates stormwater pollutants generated at industrial sites using Multi-Sector General Permits (Generic permits) for industrial facilities and a permit requirement for Municipal Separate Storm Sewer System (MS4) operators. All industrial facilities within 11 broad categories of industry are responsible for self-identifying the need to comply with the Generic permit, and subsequently, implementing self-selected pollution prevention strategies. MS4 operators are required to identify and inspect “high risk” industrial and commercial facilities that may be contributing substantial pollutant loads to the MS4, in addition to other requirements. This is partially in recognition that compliance with the Generic permit has been poor. This dual level of regulations is designed to enhance water quality protection, however, the reliance on local inspectors to develop a definition of “high risk” has led to irregular implementation. This research developed a methodology to identify industrial facilities and then screen out facilities that may not require inspection by the MS4 operator. Phone questionnaires were administered to 250 industrial facilities. Results were validated using fenceline visits and on-site inspections with local inspectors. Overall compliance by participating facilities with the Generic permit was approximately 10%. Neither the Generic permit nor the MS4 permit has been effective because numerous facilities have gone unregulated. Currently, the Generic permit has attempted to regulate too many facilities, many of which may not be affecting water quality. MS4 “high risk” inspections have not improved compliance with Generic permit either because of the prioritization of facilities. The reliance on local interpretation, which requires MS4 operators to select a definition of “high risk” based on their desired level of water quality protection and available resources, can potentially exclude many facilities from inspection. Adopting a definition of intensity for regulating industry may both improve compliance with the General permit, ensure water quality protection, and improve resource usage