Current through Register Vol. 18, September 20, 2024
(1) The
reviewing authority may require that percolation tests, conducted in accordance with
department Circular DEQ-4, be performed within the boundary of each proposed
subsurface sewage treatment system. Percolation tests must be keyed by a number on
the lot layout to the results in the report form.
(2) If the applicant or the department has reason
to believe that ground water will be within seven feet of the surface at any time of
the year within the boundaries of the treatment system, ground water monitoring must
be conducted in accordance with Department Circular DEQ-4.
(3) The applicant shall provide descriptions of
the soils within 25 feet of the boundaries of each proposed drainfield. Soil
descriptions for the proposed subdivision must meet the following requirements:
(a) Soil descriptions must be done in accordance
with Department Circular DEQ-4. The characteristics that must be addressed include,
but are not limited to, soil texture, soil structure, soil consistence, and
indicators of redoximorphic features.
(b) Soil descriptions must be based on data
obtained from test holes. Test holes must be dug in accordance with Department
Circular DEQ-4. The number of test holes must be as provided in (c), unless a waiver
is granted by the department pursuant to ARM
17.36.601. Before a waiver is granted,
the applicant shall complete test holes for 25 percent of the proposed drainfield
locations in the proposed subdivision, shall demonstrate that the soils are
consistent throughout the area requested for a waiver, and shall obtain the approval
of the local reviewing authority. The department may require additional test holes
than are required in (c) if the department determines that there is significant
variability of the soils in the proposed drainfield areas. Each test hole must be
keyed by a number on a copy of the lot layout or map with the information provided
in the application.
(c) At least one
test hole must be dug for each individual drainfield and for each shared (two-user)
drainfield. At least three test holes must be dug for each multiple-user and public
drainfield. At least one test hole must be dug for each zone of a pressure-dosed
drainfield.
(d) If the applicant or the
department has reason to believe that a limiting layer is within seven feet of the
ground surface at the site of a proposed subsurface sewage treatment system, the
department may require additional test holes and soil descriptions sufficient to
describe the suitability of the soil.
(4) Sewage systems that are subject to the design
requirements of Department Circular DEQ-2 must meet the siting requirements of that
circular.
76-4-104, MCA; IMP,
76-4-104,
MCA;
