Current through Register Vol. 30, No. 38, September 20, 2024
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.
