Pretreatment maintains an Industrial Waste Survey to identify industrial users that require regulatory oversight. The Pretreatment Program works with the Business Licensing and Building and Fire Safety Certificate of Occupancy inspection process to identify new or prospective businesses that may require this type of regulatory oversight.

Industrial Users that pose an elevated risk to the POTW or are classified in the federal regulations as a Significant Industrial User or Categorical Industrial User are required to complete a Waste Discharge Authorization Application. These permits define the facility's responsibilities and obligations, establish sampling and reporting requirements, and set limits for allowable pollutant discharge concentrations. The City's enforcement process for non-compliance with permit requirements is set forth in HMC 14.09.170 and the Pretreatment Enforcement Response Plan.

Sampling is used to determine the compliance status of an Industrial User. Inspections are used to collect and/or update changes in staffing or operations, review the facility's compliance history, identify hazards and ensure adequate protections, and identify opportunities for improvement.

Pretreatment investigates illicit discharges and odor issues. To report a complaint or other concern, please use Contact Henderson.

FOG are known to accumulate in the sewer collection system and can cause blockage and odor issues. Commercial food service establishments are required to prevent the discharge of fats, oils and grease into the sewer collection system. The most common FOG pretreatment device is the gravity grease interceptor (GGI), however other types of devices can be used under certain circumstances to prevent the discharge of FOG into the sewer.

Mercury is a potent neurotoxin that bioaccumulates in the environment. Silver colored amalgam dental fillings are made up of a mixture of metals which contains mercury. When improperly disposed or washed down a drain, amalgam waste from dental practices is a significant source of mercury releases to the environment. In an effort to reduce the amount of mercury released into the environment, the Environmental Protection Agency (EPA) promulgated 40 CFR 441 (Dental Office Point Source Category). All dental practices are required to submit a one-time Dental Practice Inventory and Certification Form.

A surcharge is assessed to Significant Industrial Users that discharge high strength waste which is waste that has a high biological oxygen demand (BOD) or contains high concentrations of total suspended solids (TSS). The surcharge rates are identified in the Department Service Rules.

Information on Salinity Control is available at: Colorado River Basin Salinity Control Program

This letter serves as official notice to Industrial Users (IU) about the PFAS concerns and pending regulations. The letter is also intended to provide advanced awareness that self-monitoring requirements &/or adherence to best management practices (BMPs) may soon be required for permitted IUs which use PFAS-containing materials are part of their operations.

• Notification of Pending PFAS Regulation (12/2023)