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 technol- ogies covered by a Type 4 General Permit alone or in combination with another Type 4 General Permit to over- come site limitations.

2.        An applicant may submit a single Notice of Intent to Dis- charge for an on-site wastewater treatment facility con- sisting 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 Authoriza- tion 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.

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 con- ducted 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 sedi- ments 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 Dis- charge 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 installa- tion of a septic tank and disposal works system described in R18-9-E302 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 modi- fied 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 con- ditions are identified at the site:

a.         An outcropping of rock that cannot be excavated or will impair the function of soil receiving the dis- charge 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 sea- sonal high water table is less than the minimum ver- tical  separation   distance,  as  described   in  R18-9-

A310(D)(2)(c); 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 dis- posal works system described in R18-9-E302 is appropri- ate 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 mainte- nance costs than a septic tank and disposal works system described in R18-9-E302.

Historical Note

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).