Clean Water Act

The Federal Water Pollution Control Act was amended in 1977. These amendments are also known as the Clean Water Act (CWA). The overall framework of the National Pre-Treatment Program is contained in the General Pre-Treatment Regulations that EPA published in 1977. The General Pre-Treatment Regulations can be found in 40CFR 403.


The amendments require the local Publicly Owned Treatment Works (POTWs) with capacities greater than 5 million gallons per day or those with significant industrial discharges to establish Pre-Treatment programs. In other words, the administration of the Pre-Treatment Program was delegated from EPA to the local level.


The decision to delegate the Pre-Treatment program to the local POTWs was based on several factors. First, EPA realized it was having a difficult time implementing the Pre-Treatment program. Second, POTW officials are familiar with their industrial users. Third, the POTWs are in a better position to understand and correct problems within their own treatment systems. Finally, the POTW is the logical level of government to respond to emergencies in the treatment system.


The Pre-Treatment program for the Arapahoe County Water and Wastewater Authority (ACWWA)has been established to provide protection for the publicly owned treatment works (POTW) and the sewer collection system by controlling the introduction of non-domestic pollutants into the POTW. This program uses Appendix C to ACWWA's Rules and Regulations to enforce prohibitions and standards.

How the Program Works

Inspection, sampling, documentation and public education are the basis of ACWWA's program. Inspection and sampling ensure that pollutants and wastes are being discharged and /or handled by the commercial or industrial user (IU) in compliance with ACWWA's sewer use ordinances. Documentation gives ACWWA a hard copy of sampling, inspections and any event that may have occurred. Public education offers ACWWA the opportunity to give the public and industry an overview of the Pre-Treatment program, provide assistance in program compliance and answer questions.


All permitted industries get inspected. Permitted industries include, but are not limited to; electroplaters, laundries, restaurants, automotive repair shops, photofinishers, carwashes, dry cleaners, radiator shops, etc.  

Facility Classification

All facilities are evaluated by the information provided on the wastewater questionnaire and inspection before being classified. Facilities are classified as significant industrial users (SIU) if they fall under the federal definition of a significant or categorical industry.

Class I

Industrial users are defined as facilities that have no reasonable potential for adversely affecting the POTW (ACWWA) operation or for violating any Pre-Treatment standard.

Class II

Industrial users are defined as facilities that have materials or wastes that may impact ACWWA facilities in a negative manor. These wastes include, but are not limited to; hazardous wastes and materials, pH, and other non-conventional pollutants.

Class III

All industrial users are subject to Categorical Pre-Treatment standards and industrial users whose discharge may have an adverse effect on the POTW (ACWWA).

Pre-Treatment Documents