Industrial Wastewater Control (IWC)

For more information
Wastewater Control

(520) 724-6200 or

The Pima County Industrial Wastewater Control (IWC) section is responsible for implementing the federally mandated Pretreatment Program. The Pretreatment Program regulates industrial facilities discharging wastewater to publicly owned treatment works (POTWs). These facilities, known as industrial users, discharge process wastewater often contaminated by a variety of toxic or otherwise harmful substances. Because POTWs are usually not specifically designed to treat these substances, Pretreatment Programs are needed to eliminate potentially serious problems that occur when these substances are discharged into the public sanitary sewerage system .

Pollutants in industrial wastewater may compromise municipal treatment plant processes or contaminate receiving streams and environment. To protect municipal treatment plants and the environment, the Pretreatment Program requires industrial dischargers to use treatment techniques and management practices to reduce or eliminate the discharge of harmful pollutants to sanitary sewers. The Pretreatment Program is a core part of the Clean Water Act's National Pollutant Discharge Elimination System (NPDES).

The goal of all Pretreatment Programs is to keep harmful substances out that could:
2021 AR cover
  • Damage sewer systems and treatment plant structures
  • Interfere with treatment operations
  • Jeopardize worker safety by exposure to chemical hazards
  • Reduce reclamation options due to contaminated effluent and biosolids
  • Result in violations of the treatment facilities' own Discharge Requirements
  • Add maintenance, repair, operational and disposal costs to the treatment of wastewater

IWC Ordinance

P.C.C. Section 13.36.060 was revised in March 2020 to reflect additional discharge restrictions for aqueous film forming foams (AFFF). 

Enforcement Actions

The Pima County Regional Wastewater Reclamation Department (RWRD) is tasked as the enforcement authority for the Pretreatment Program. Regulations are enforced through actions that could escalate from simple Notice of Non-compliance to a Cease and Desist Order if discharges constitute a public health and safety issue. Compliance through pollution prevention measures instead of enforcement actions is highly preferred. Increasing facility inspections have played an active role in improving communication with industries and the overall compliance rate in the last five years. The protection of the environment is achieved through a partnership between government and industry
Enforcement Response Plan

Industrial Wastewater Discharge Program

Commercial facilities that discharge regulated wastes into the sewers, such as metal finishers, car washes, auto repair shops, photo developers, military facilities and hospitals, must have industrial discharge permits. Pima County Development Services and RWRD's IWC section can help you determine what types of discharge require a permit.

Septage Haulers

Grease Management Program

A thriving business community is vital to Pima County and its neighborhoods. A healthy economy benefits every Arizonan, but when businesses discharge grease into the sewers, it can cause sanitary sewer overflows and interfere with the County’s sewage treatment operations.

RWRD is responsible for maintaining the County’s public sanitary sewerage system and for enforcing the Industrial Wastewater Ordinance {Ordinance 2013-32, §13.36.400, Article XIV, Grease Management Program}. Sewer back-ups are a major sewer system problem that damages property and affects public health. In some areas, back-ups are frequently caused by grease clogging the local sewers. To address this problem, RWRD is helping businesses comply with the County’s Industrial Wastewater Ordinance, which also include requirements concerning the proper sizing, installation, and maintenance of grease interceptors. RWRD is educating not only restaurant owners but also operators of nursing homes, hospitals, laundries, and dry cleaners, among others, to keep grease and other materials and chemicals out of the public sanitary sewerage system .


Dental Facility

Pima County Regional Wastewater Reclamation Department's (PCRWRD) Industrial Wastewater Control Section is responsible for monitoring and controlling non-domestic wastewater discharges into our sanitary sewer system. As you may be aware, on June 14, 2017, the Environmental Protection Agency (EPA) established Effluent Limitations Guidelines and Standards for the Dental Category (40 CFR Part 441) that became effective on July 14, 2017. The rule applies to wastewater discharges to PCRWRD from offices where the practice of dentistry is performed, including: large institutions such as dental schools and clinics; permanent or temporary offices; home offices; and dental facilities owned and operated by the military and federal, state, or local governments. The EPA rule requires the above listed dental facilities to submit to PCRWRD a One-Time Compliance Report.

In an effort to make this process as easy as possible for dental practices in Pima County, and to assist in your compliance with this federal requirement, we developed the enclosed Dental Amalgam Survey. Please complete a survey for each facility that you operate and in which dentistry is performed.

Additional Resources

Follow Wastewater Reclamation on Social MediaShare the Vector (Roach) Control page.

Wastewater Reclamation

201 N. Stone Ave., 8th Fl.
Tucson, AZ 85701

Customer Service: 
(520) 724-6500
Customer Service Hours:
8:00 a.m. — 4:00 p.m.
24-Hour Sewer Emergencies: 
(520) 724-3400
Service Request Online Portal

Wastewater Reclamation Department Home Page
Wastewater Reclamation Department News
Wastewater Reclamation Department Directory
Send Wastewater Reclamation Feedback
Wastewater Reclamation Boards, Commissions and Committees
Appeal Sewer Bill
Report an Odor to Wastewater Reclamation
Report an Odor to Wastewater Reclamation
Public Works Quick Guide
Wastewater Reclamation Permitting
Wastewater Reclamation Regulatory Bill of Rights
Volunteer with Pima County

WaterISAC logo