Significant and Categorical Industrial Users


The Board of Public Utilities implements and enforces National Pretreatment Program requirements.

The EPA classifies two special types of industrial users. The first is Significant Industrial User (SIU) which is primarily based on the quantity of water discharged and how it relates to the publicly owned treatment works (POTW). The second is a Categorical Industrial User (CIU) which is based on the type of industry. The Board of Public Utilities has both Significant and Categorical Users discharging to our sanitary sewer system.

Industrial and commercial users that are of a certain size (SIU) or type of industry (CIU) may have wastewater that contains pollutants at levels that could affect the environment or the infrastructure of the publicly owned treatment works (POTW). Federal requirements have been established for a number of industrial categories. Additionally, the Board of Public Utilities regularly completes a study to develop local limits. Local limits consider the type and quantity of pollutants our wastewater treatment facilities can treat. The study also accounts for what type and amount of pollutants come from residential users on a regular basis, and a portion of the remaining amount of pollutant that the treatment facilities can treat is allotted for these large or specialized industrial users. Permits are issued to these industrial users, explaining what limits their wastewater must meet prior to being discharged into the sewer system, what parameters to sample for and how often, and other types of requirements especially for industrial users.