Current through Register Vol. 47, No. 5, March 10, 2024
A. The
OWTS for single-family homes shall be designed to accommodate the proposed
flows from the structure as defined in 43.6.A.2. Flow estimates for
multi-family or commercial OWTS must comply with 43.6.A.4 Expected waste
strength as noted in Table 6-3 and Table 6-4 must also be addressed, where
applicable. Installation of low flow fixtures or the separation of toilet waste
or other sources of wastewater does not allow for the reduction in the size of
an OWTS.
B OWTS shall be designed
and constructed to achieve the treatment level specified by the
design.
C. OWTS must be designed
and constructed such that each component shall function, when installed and
operated, in a manner not adversely affected by normal operating conditions
including erosion, corrosion, vibration, shock, climatic conditions, and usual
household chemicals. Each component must be free of non-functional protrusions
or sharp edges, or other hazards, which could cause injury to persons, animals,
or properties. Design must be such as to exclude flies and rodents and other
vectors and to prevent the creation of nuisances and public health hazards and
must provide for efficient operation and maintenance.
D. Accessibility for Inspection, Maintenance,
and Servicing
1. Septic tanks must have
watertight risers over each access manhole and all risers must extend to or
above final grade.
2. For new
construction, the top of any septic tank, dosing tank or vault must be no
deeper than four feet below finished grade.
3. Each treatment component of an OWTS other
than the septic tank and soil treatment area must be equipped with access
manholes with risers that extend to or above final grade, located to permit
periodic physical inspection, collection and testing of samples and maintenance
of all components and compartments.
4. Riser Lids
a. Each riser lid must be watertight, brought
to or above the surface, and must have a secure closing mechanism, such as a
lock, special headed bolts or screws, or sufficient weight (defined as 59
pounds) to prevent unauthorized access.
b. A local public health agency may require a
secondary plug, cap, cover or screen be provided below the riser cover to
prevent tank entry if the cover is unknowingly damaged or removed.
5. Components that require access
for maintenance must include but not be limited to submerged bearings, moving
parts, pumps, siphons, valves, tubes, intakes, slots, distribution boxes, drop
boxes, cleanouts, effluent screens, filters, inlet and outlet baffles,
aerators, treatment equipment and other devices.
6. Components must be designed and
constructed so that, when installed, they must be easily maintained, sampled,
and serviced according to the manufacturer's recommendations. Easy physical
access to treatment components by maintenance personnel and equipment must be
provided.
E. Plumbing
Codes: Plumbing fixtures, building sewers, vents, sewer lines and other
appurtenances must be designed, operated and maintained so as to comply with
the minimum requirements of the most recently revised locally enforceable
plumbing code. In absence of a local plumbing code, designs must adhere to the
Colorado Plumbing Code (3 CCR 720-1). A local plumbing
permit may be required.
F.
Electrical Equipment, If Used
1. All
electrical work, equipment, and material must comply with the requirements of
the currently applicable National Electrical Code as designated by the State
Electrical Board Rules and Regulations (3 CCR 710-1).
A local electrical permit may be required.
2. Electrical components must be protected
from moisture and corrosive gases.
G. Indicators of Failure or Malfunctioning
for Systems Utilizing Mechanical Apparatus: A signal device must be installed
which will provide a recognizable indication or warning to the user that the
system or component is not operating as intended. This indication or warning
must be a visual signal and an audible signal, and be located in a centralized
area within visual and audible range of the system user. A signal or message
may also be sent remotely to a maintenance provider.
H. Sampling Access
1. If sampling for testing or as a
requirement for a permit will be required of effluent from a component other
than the soil treatment area, an accessible sampling point must be
provided.
2. If sampling of the
treated wastewater from the soil treatment area will be required for testing or
as a requirement for a permit, a monitoring well or wells must be constructed.
Monitoring wells must be located down gradient from the soil treatment area,
accessible, and provided with a properly securable cover at or above the ground
surface. Monitoring wells up gradient of the system may also be required.
Lysimeters or other collection devices under the soil treatment area may be
used instead of a monitoring well if approved by the local public health agency
or other issuer of a permit.
I. Component Operating Instructions
1. The manufacturer of proprietary treatment
units utilizing mechanical components must provide clear, concise written
instructions covering the components which, when followed, must assure proper
installation and safe and satisfactory operation and maintenance.
2. If the OWTS uses public domain technology,
the design engineer must provide clear, concise written instructions covering
the components which, when followed, must assure proper installation and safe
and satisfactory operation and maintenance.
J. Surface Activity: Activity or use on the
surface of the ground over any part of the OWTS must be restricted. The soil
treatment area must not be subject to damage or soil compaction from livestock,
vehicular traffic, recreational use, or other site development activity.
Construction equipment not necessary to install the OWTS must be kept off of
the soil treatment area to prevent undesirable compaction of the soils. If
compaction occurs, the disturbed or compacted soil must be re-evaluated and/or
new soil evaluations performed. The system must be redesigned if the soil
permeability have changed.
K.
Floodplains
1. A new, expanded or
repair/replacement OWTS installed in a 100-year floodplain must meet or exceed
the requirements of the Federal Emergency Management Agency and the local
emergency agency. Repairs of an existing system must meet the requirements as
feasible. The system as approved by a local public health agency must be
designed to minimize or eliminate infiltration of floodwaters into the system
and discharge from the system into the floodwaters. The OWTS must be located to
avoid impairment to floodwaters or contamination from them during
flooding.
2. A new or expanded OWTS
must not be installed in a floodway designated in a 100-year floodplain where a
conforming OWTS outside the floodway can be installed. For any new OWTS or
system repair that may affect the floodway delineation, appropriate procedures
must be followed including revision of the floodway designation, if
necessary.
L. Business
Commercial, Industrial, Institutional or Multi-Family Dwelling Wastewater
Systems
1. An OWTS that will serve a business,
commercial, industrial or institutional property, or a multifamily dwelling
must:
a. Be designed by a professional
engineer;
b. Receive only such
biodegradable wastes for treatment and distribution as are compatible with
those biological treatment processes as occur within the septic tank, any
additional treatment unit and the soil treatment area; and
c. Receive authorization by rule or a class V
underground injection permit from the United States Environmental Protection
Agency (EPA) before an application for an OWTS permit is approved if the system
may receive non-residential wastewater or is otherwise covered by the EPA
underground injection control program. Subsequent to acceptance by the EPA, the
local public health agency may choose to also issue a permit for this type of
use.
