HomeMy WebLinkAboutOWTS Installation Observations 12.13.2021CBO Inc.
129 Cains Lane
Carbondale, CO 81623
970.309.5259
carla.ostberg@gmail.com
December 13, 2021 Project No. C1511
Gary Littell
gary@littellelectric.com
Onsite Wastewater Treatment System (OWTS) Installation Observations
969 CR 113
Garfield County, Colorado
OWTS Permit SEPT-6221
Gary,
CBO Inc. observed the installation of the onsite wastewater treatment system (OWTS) on June 5 and 9,
2020 for the subject property. Hagist Excavation installed the system.
The existing septic tank was abandoned by pumping and crushing the top, sides, and bottom and filling the
void with on-site material. The existing STA was abandoned in place.
We verified the minimum required setback from the well to the septic tank and STA.
The OWTS design is based on 5-bedrooms in the main house and 1-bedroom in a future accessory
dwelling unit (ADU). An average daily wastewater flow of 750 GPD was used. The ADU may be
constructed at a later date. A new, minimum 1000-gallon septic tank will be required to serve the ADU at
the time of construction. An OWTS Permit must be obtained for the septic tank installation at the time the
Building Permit is obtained. The soil treatment area (STA) has been sized to accommodate both the
main house and future ADU.
The sewer line exiting the residence was replaced with 4-inch diameter sewer pipe with a double-sweep
clean out and a minimum 2% grade to the septic tank.
The system installation included a 2000-gallon, two-compartment concrete septic tank with Orenco®
ProPak with a PF3005 pump in the second compartment of the septic tank. There is an effluent filter in
the second compartment of the septic tank that must be cleaned annually, or as needed. The floats
were set to dose approximately 70 gallons each pump cycle. The control panel for the pump is mounted
on a post within line of sight of the septic tank.
A 1.5-inch diameter Schedule 40 pump line was installed from the pump to an Orenco® automatic
distributing valve (ADV), model 6404. The ADV was placed a high point in the system in an insulated riser
with access from grade.
Effluent is pressure dosed through FOUR 1.5-inch diameter pipes to two beds, each with 4 rows of 10
‘Quick 4’ Low Profile Infiltrator® chambers, for a total of 80 chambers and 960 square feet of infiltrative
area. Laterals were hung with zip ties from the underside of the chambers. Laterals have 5/32-inch
diameter orifices facing up, with the exception of the first and last holes facing down for drainage. The
orifices were drilled 3-feet on center. Each lateral ends in a 90-degree ell facing up with a ball valve for
flushing. Valves were placed in a valve box, accessible from grade, for access. Inspection ports were
placed in each corner of each bed. Ports were cut to grade and covered with a valve box for access.
1-1-2022
The OWTS was generally installed according to specifications. This observation is not a guarantee of
workmanship and/or parts and materials. CBO Inc. should be notified if changes are made to the OWTS
in the future. Any additional OWTS construction must be according to the county regulations.
LIMITS: Observations are limited to components that are visible at the time of the inspection. The installer must
have documented and demonstrated knowledge of the requirements and regulations of the county in
which they are working. The quality of the installation is dependent of the expertise of the installer, soil
type, and weather conditions.
Please call with questions.
Sincerely,
CBO Inc. Reviewed By:
Carla Ostberg, MPH, REHS Romeo Baylosis, P.E.
STA layout Chambers in bed
Tank in the middle of beds
Flushing valves
ADV
STAs backfilled Inspection ports and flushing valves
832‐R‐13‐002