State Rules:
The Arizona Administrative Code Title 18 (AAC R18-9), Water Pollution Control, covers wastewater permitting under the Aquifer Protection Permitting (APP) process with the purpose of protecting groundwater from degradation. Click here to read more.

Permits are broken down into individual permits and general permits. General Permits cover sewer collection systems including pipes and lift stations, and treatment and disposal systems (on-site wastewater) for one house or business. A new or upgrade to a wastewater treatment plant serving more than one house or business requires an individual permit. These types of individual permits are reviewed and approved by the Arizona Department of Environmental Quality (ADEQ). An individually owned wastewater system generating more than 24,000 gallons per day also requires an individual permit. These permits may be reviewed by ADEQ or the County depending on the location.

Mills Engineering is familiar with the state regulations and can help you determine how your project can comply with the requirements, the permitting costs, and help you through the permitting process.

County Delegation:
ADEQ has delegated various Counties different aspects of the review of wastewater systems. The delegation agreements are available at the ADEQ website for review.  Click here to read more.

Mills Engineering can help you determine who will review your project, the requirements of the agency, and help you meet their requirements.

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On-site Wastewater/Septic Systems
New Construction, The steps for your septic system project include:

1. Site and soils Evaluation by the regulatory agency (Phase 1) or Mills Engineering to determine if there are any limiting conditions present or if a sewer system connection is within 400 feet and feasible.

2. Notice of Intent to Discharge (NOID) application
Design of the system by Mills Engineering based on building and site plan and limiting conditions: Residential: number of bedrooms and number of fixture units; Commercial: based on use and wastewater generation rates and plumbing fixtures

3. Construction Authorization (CA) – County or state approves the design.

4. Construction of the system by contractor followed by review of the installed system

5. Discharge Authorization (DA) – After construction and review by the county or designer, system is authorized to operate by the regulatory agency. For alternative treatment systems, a contract with a certified operator may be required.

If the house changes include a change in the number of plumbing fixtures and/or bedrooms, the existing septic system will likely require expansion or replacement. Soil evaluation and design followed by filing the NOID will be required. The records of the system may be found by contacting your county health department. 

Septic systems may fail for a number of reasons: age, soil plugging from salts build up, improper maintenance, damage, etc. Replacement of the entire system requires the steps shown above for new construction. For alterations or repairs, a smaller fee is charged, but the same process as new construction is followed.

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Local and Regional Wastewater Systems
Gravity Sewer System, Lift Station, and pressurized force main pipe

The steps to permit a larger project include:
Connection to existing system, authorized by the owner with enough capacity in the pipes, treatment plant, and disposal system

1. Notice of Intent to Discharge (NOID) application: The application and construction plans showing design of the system, specifications, a design report, authorization from the owner if you are connecting to another system, and draft Operation and maintenance manual are required. Mills Engineering can help you by designing the system and writing the reports and draft manual.

2. Construction Authorization: The regulatory agency reviews the NOID and requests more information or approves the design.

3. System is constructed and operation and installation are reviewed by Mills Engineering. An Engineer’s Certificate of Completion is submitted to the regulatory agency with test results.

4. Discharge Authorization: The regulatory agency reviews the certificate and may visit the project before issuing the DA that authorizes operation of the completed system. For most larger projects that do not become part of an existing system, a certified operator will be required to oversee the operation.

Wastewater Treatment Plant or Treatment Plant Expansion
208 Plan Small Plant Review or Amendment

The permitting process that is required to expand a wastewater treatment facility or construct a new one includes the 208 Amendment or Small Plant Review. The concept for the plant must follow the 208 Plan, a regional wastewater plan to protect the environment, following Section 208 of the Clean Water Act. The state of Arizona is divided into different regions with a governmental agency overseeing the 208 plan in each region. Some examples are the Central Arizona Association of Governments, Maricopa Association of Governments, and Pima Association of Governments. Members of the associations are representatives of local governments. The associations review the changes to the 208 plan to oversee regional wastewater planning.

The first step for a 208 Plan Amendment or Small Plant Review is to complete a Design Concept Report and 208 Report detailing the scope of the project. This document is reviewed by neighboring communities and the community that will submit it to the association for review.

After approval by neighboring communities, the association will review the document followed by the Arizona Department of Environmental Quality and Environmental Protection Agency.

Plant Design
Once the plant has been approved by the government association, detailed Design of plant and sewer system will continue. Construction plans and specifications and a draft operation and maintenance manual are prepared for review by the delegated County or Arizona Department of Environmental Quality (ADEQ).

Aquifer Protection Permit
An Individual Aquifer Protection Permit Application is also submitted to ADEQ, who reviews it for Administrative Completeness, Technical Completeness, issues a Draft Permit, gives Public Notice, and issues a final permit.

Certificate of Completion and Discharge Authorization
Once the plant is constructed, operation and installation are reviewed by Mills Engineering. Once all punch list items are addressed, the Engineer’s Certificate of Completion is submitted to the regulatory agency along with test results.

The agency reviews the submittal and may visit the installation before issuing the Discharge Authorization. The final APP permit and 208 Plan approval is required before operation can begin. The operation and startup of the plant follows.

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State Rules:
The Arizona Administrative Code Title 18 (AAC R18-4 and 5, Article 5), Safe Drinking Water and Environmental Reviews and Certification, cover water system permitting with the purpose of providing safe drinking water for public consumption. Click here to read more:  Chapter 4, Chapter 5

Mills Engineering is familiar with the rules for water system design and compliance and can help you plan and complete your water system.

The permitting process consists of:
1. Submitting an application for Approval to Construct (AtC) with the design report, construction plans and specifications, draft operation and maintenance manual and water quality sample results, if needed. Mills Engineering can design the system and submit the permit application to the delegated agency.

2. Review by the regulatory agency and issuance of the Approval to Construct.

3. Construction of the system and review of the installation and operation by Mills Engineering. Sample testing for verification of disinfection or required treatment.

4. Submitting the Engineer’s Certificate of Completion, final O and M manual and Application for Approval of Construction (AoC) to the regulatory agency.

5. Review by the regulatory agency and issuance of the Approval of Construction. A certified operator will be required to oversee it if it is a community water system.

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