Ariz. Admin. Code § 18-9-A311

Current through Register Vol. 30, No. 24, June 14, 2024

Section R18-9-A311 - Facility Selection for Type 4 On-site Wastewater Treatment Facilities

A. A person shall select, design, and install an on-site wastewater treatment facility that is appropriate for the site's geographic location, setback limitations, slope, topography, drainage and soil characteristics, wastewater infiltration capability, depth to the seasonal high water table, and any surface or subsurface limiting condition.

1. A person may use on-site treatment and disposal technologies covered by a Type 4 General Permit alone or in combination with another Type 4 General Permit to overcome site limitations.

2. An applicant may submit a single Notice of Intent to Discharge for an on-site wastewater treatment facility consisting of components or technologies covered by multiple general permits if the information submittal requirements of all the general permits are met.

3. The Director shall issue a single Construction Authorization under R18-9-A301(D)(1) and a single Discharge Authorization under R18-9-A301(D)(2) for an on-site wastewater treatment facility that consists of components or technologies covered by multiple general permits.

4. If either a septic tank or disposal method, or both, as identified in R18-9-E302, is appropriately used in combination with an alternative technology listed under R18-9-E303 through R18-9-E322, the applicant shall apply the design requirements specified in R18-9-E302, except that the specific requirements for R18-9-E303 through R18-9-E323, as applicable, supersede requirements in R18-9-E302 if the rules conflict. If additional modifications are necessary and appropriate to ensure adequate treatment, the applicant may request review under R18-9-A312(G) to allow the Department to approve the application.

B. A person may install a septic tank and disposal works system described in R18-9-E302 as the sole method of wastewater treatment and disposal at a site if the site investigation conducted under R18-9-A310 indicates that no limiting condition identified under R18-9-A310(C) or R18-9-A310(D) exists at the site.

1. A person may install a seepage pit only in valley-fill sediments in a basin-and-range alluvial basin and only if the seepage pit performance test results meet the criteria specified in R18-9-A312(E).

2. The person shall specify in the Notice of Intent to Discharge that no limiting conditions described in R18-9-A310(C) and (D) were identified at the site.

C. If any surface or subsurface limiting condition is identified in the site investigation report, an applicant may propose installation of a septic tank and disposal works system described in R18-9-E302 as the sole method of wastewater treatment and disposal at a facility only if:

1. The applicant submits information under R18-9-A312(G) that describes:

a. How the design of the septic tank and disposal works system specified in R18-9-E302 was modified to overcome limiting conditions;

b. How the modified design meets the criteria of R18-9 -A312(G)(3); and

c. A site-specific SAR under R18-9-A312(D)(2)(a) or (b), as applicable; and

2. None of the following surface or subsurface limiting conditions are identified at the site:

a. An outcropping of rock that cannot be excavated or will impair the function of soil receiving the discharge exists in the intended location of the on-site wastewater treatment facility, as described in R18-9-A310(C)(2)(e);

b. The vertical separation distance from the bottom of the lowest point of the disposal works to the seasonal high water table is less than the minimum vertical separation distance, as described in R18-9-A310(D)(2)(b); or

c. A subsurface condition that promotes accelerated downward movement of insufficiently treated wastewater as described in R18-9-A310(D)(2)(e).

D. If a site can accommodate a septic tank and disposal works system described in R18-9-E302, the applicant shall not install a treatment works or disposal works described in R18-9-E303 through R18-9-E322 unless the applicant submits a statement to the Department with the Notice of Intent to Discharge acknowledging the following:

1. The applicant is aware that although a septic tank and disposal works system described in R18-9-E302 is appropriate for the site, the applicant desires to install a treatment works or disposal works authorized under R18-9-E303 through R18-9-E322; and

2. The applicant is aware that a treatment works or disposal works authorized under R18-9-E303 through R18-9-E322 may result in higher capital, operation, and maintenance costs than a septic tank and disposal works system described in R18-9-E302.

Ariz. Admin. Code § R18-9-A311

New Section adopted by final rulemaking at 7 A.A.R. 235, effective January 1, 2001 (Supp. 00-4). Amended by final rulemaking at 11 A.A.R. 4544, effective November 12, 2005 (05-3). Amended by final rulemaking at 29 A.A.R. 1023, effective 6/19/2023.