Collection Systems Operating With CMOM Permits

Some wastewater collection systems operate under Capacity, Management, Operation and Maintenance (CMOM) permits in accordance with the provisions of the Arizona Administrative Code (AAC), Title 18, Chapter 9, Section C305. A CMOM permit is issued by the Arizona Department of Environmental Quality (ADEQ) and allows a permittee to manage, operate, and maintain a wastewater collection system under the terms of an approved CMOM Plan.

Reporting Characteristics


Some characteristics of CMOM permits that affect Sanitary Sewer Overflow (SSO) reporting:
  • Wastewater spills of less than 50 gallons do not have to be reported.
  • Wastewater spills between 50 - 2,000 gallons only have to be reported if there is an "imminent and substantial threat to public health or the environment."
  • Wastewater spills greater than 2,000 gallons must be reported.
The definition of "imminent and substantial threat to public health or the environment" is explained in AAC R18-9-C305 (A). Refer to the AAC for additional details about the specific rules and regulations governing CMOM permits.

Health Code


Although the MCESD is not delegated CMOM permitting responsibilities by the ADEQ, the Maricopa County Environmental Health Code (MCEHC) recognizes CMOM permits as related to wastewater spills as noted in Chapter 2, Section I, Regulation 2b of the MCEHC. If a utility is operating under a CMOM permit a Spill Notification Report and a Written Spill Report is required to be submitted to the Treatment Program:
  • For critical wastewater spills between 50 - 2,000 gallons.
  • For all wastewater spill greater than 2,000 gallons.
Wastewater spills of less than 50 gallons do not have to be reported.

Please note that the CMOM permit requires that all critical spills greater than 50 gallons but less than 2,000 gallons and all spills greater than 2,000 gallons must be recorded and submitted in an annual report to the ADEQ. The MCESD requires that a copy of this annual report be submitted to the Treatment Program.