HomeMy WebLinkAboutEngineer's OWTS Design PlanProposed Single-Family OWTS System
Onsite Wastewater Treatment System Design
3-BR Single-Family Residence
146 Quicksilver Court
Rifle, CO 81650
Parcel No. 217 7 -27 2-01-001
Prepared for:
Clayton Homes
Julyo 2025
Digitall! signed by
Jeremy: Gilliam
Date:2025.07.31
1 1 :1 3:57-06'00'
Prepared by:
4 -Ngst Water E ry g i n ee ri n g
€ Environmental Consultin g Selvices
2516 Foresight circle #1, Grand Junction, Co 81505 Telephone: (970)241-7076
I.O SCOPE
This report presents the findings of an On-Site Wastewater Treatment System (OWTS) design
for a proposed three-bedroom (3-BR) single-family residence at 146 Quicksilver Court in Rifle,
Colorado. The purpose of this report was to establish design criteria for a new OWTS system.
The report includes an assessment of observed subsoil and groundwater conditions, percolation
test results, and the design and construction parameters for the OWTS. The findings are based on
data gathered from field percolation testing and engineering evaluation based on experience with
similar site conditions.
2.0 DESIGN SUMMARY
l. Encountered subsurface conditions in the test pits consisted of one foot of silty sandy
clay topsoil underlain by sandy silt to the maximum depth explored of 8 feet below
ground surface, with scattered gravels noted. (Appendix A for visual and tactile
evaluation). Groundwater was not encountered at the time of observation to 8 feet
below ground surface.
2. The percolation result at the elevation of infiltration was 11.5 minutes per inch. We
determined from Table 10-1 of Garfield County's On-Site Wastewater Treatment
System Regulation (Regulations) that the treatment area soil type is Type I and used
"Long Term Acceptance Rate" (LTAR) :0.8 gallons per day per square foot.
3. The design system will utilize a new CDPHE approved 1,000 gallon septic tank,
which will discharge effluent to four (4) new Quick 4 Plus Infiltrator trenches, each
with nine (9) units, for a total minimum disturbed area of about 24 feet by 39 feet,
including 4 feet separation distance between trenches and chamber end caps.
4. Design placement based on setbacks and comparison to minimum requirements,
which must be confirmed prior to installation by the licensed installation contractor.
3.0 EXISTING SITE CONDITIONS
The 1.13-acre parcel located at 146 Quicksilver Court was a barren lot with scattered
infrastrucfure. In the vicinity of the new construction, the lot slopes down to the northeast at
approximately lo/o.
4.0 PROPOSED SITE IMPROVEMENTS
A proposed three-bedroom (3-BR) single-family residence is to be constructed. The structure
will have no below grade/basement areas. If the proposed construction differs from what is
described above, WestWater Engineering should be notified to re-evaluate the recommendations.
The new 3-BR dwelling will be served by a new 1000-gallon septic tank (minimum) and atotal
of 36 new Standard Plus Quick4 Infiltrator@ units configured in four (4) trenches, each with nine
(9) Q4 Plus units for a minimum 24' x 39' footprint including 4 feet separation distance between
trenches and chamber end caps (FigureB2).
Page I
5.0 SOIL INVESTIGATION
WestWater Engineering collected soil and percolation data on June26,2025, in accordance with
the Regulations. The soil profile in the vicinity of the proposed Soil Treatment Area (STA)
shows topsoil I foot below ground surface underlain by sandy silt to the maximum depth
explored of 8 feet below ground surface. No groundwater was encountered at the time of
observation (Appendix A).
Percolation rates ranged from I 1.9 to I 1.2 minutes per inch (Appendix A). WestWater
Engineering finds the average percolation rate of 11.5 minutes per inch to be most applicable.
Based on the Garfield County, On-Site Wastewater Treatment System Regulations effective
April20, 2023, Table 10-1, the soil type was determined as Soil Type l, Long Term Acceptance
Rate (LTAR):0.8 gallons per day per square foot, which most nearly describes the condition
for this site and proposed construction.
6.0 OWTS WASTEWA DESIGN FLOW
Per guidelines, the occupancy is six (6) persons, tabulated as 2 people per bedroom for the first 3
bedrooms. The design flow is six (6) persons x 75 gallons per day per person : 450 gallons per
day (per Table 6-1 of the Regulations).
7.0 OWTS DESIGN
Septic Tank
The minimum septic tank capacity required to service a total of three (3) bedrooms is 1,000
gallons in accordance with Table 9-1 of the Regulations. The minimum required septic tank
volume will provide a 48-hour (2-day) particle detention time for the wastewater flow capacity
of the proposed OWTS. The required capacity of 1,000 gallons exceeds the estimated daily
wastewater flow of 450 gallons per day (GPD) over a two-day period (450 GPD x 2 days:900
gallons), ensuring compliance with the Regulations. The tank shall be equipped with locking or
secured access lids to prevent unintended access, as well as an effluent screen (or filter) at the
tank outlet.
Furthermore, the proposed 1,00O-gallon septic tank for the OWTS shall be selected from the
current Colorado Department of Public Health and Environment (CDPHE) approved septic tank
list.
Distribution Box
For this design, use a new distribution box (D-box) approved for use in Garfield County. Ensure
that the flow is equal between laterals by using flow equalizers in the D-box, and access is
available for maintenance and inspection via an approved riser assembly with a locking lid.
Sbil Treatment Area (STA)
Sandy silt occurring at the 4.O-foot depth interval will be used for the upper infiltrative surface
for the proposed STA (Figure B3). Maximum trench depth must not exceed 4 feet in accordance
Page 2
with the Regulations. Trench excavation will remove approximately 4.0 feet of soil and upper
root mass to prepare the level surface for installing infiltrators on the receiving soil infiltrative
surface, providing secondary treatment of discharged wastewater. Soil should not be wet at the
time of excavation. Soil covering the STA must be crowned over proposed trenches or match
the existing grade so water runs off and is not ponded over any area of the STA. Prior to
backfilling the final soil cover, a pervious soil barrier of non-woven geotextile fabric (2 ozlyd2
minimum) or similar pervious material shall be installed over the STA to prohibit soil intrusion
(See Figure 83 - OWTS Cross Section). All setback distances in accordance with the
Regulations are applicable to septic system installation.
The following design calculations propose to discharge septic tank effluent to four (a) Quick4
Plus Infiltrator trenches, each with nine (9) units, for a total minimum disturbed area of about24
feet by 39 feet, including 4 feet separation distance between trenches and chamber end caps. A
total of 36 Quick 4 Standard Plus Infiltrator units will be installed in the four-trench
configuration, which is generally oriented south to north. It should be noted that other
manufacturers of infiltrators can be used, but the use of alternative system components will
require verification by the Engineer to determine conformance with design requirements for this
system.
Destan Flow
STA = Lf AR x Method x Media (1)
Where:
STA:
Design Flow:
LTAR:
Method:
Media:
Total surface area required to effectively discharge sewage effluent
Estimated volume of wastewater per day
Long-Term Acceptance Rate of soil treatment area
Method of effluent application and type of soil treatment area
Type of distribution media
STA
Total Chambers = cham
The County and State approved bottom chamber area for Quick 4 Plus
Standard Infiltrator tJnit, 12 ft2
(2)
Where:
Chamber Area:
Page 3
If,
Per Regulations Table 6-1,
Design Flow : 450 Gallons/Day
Long Term Acceptance Rate (LTAR) review of Regulations Table l0-1,
LTAR : 0.8 Gallo nslDay lF oot2
The type of application for this system is a gravity-fed trench system, per Regulations Table l0-)
Method: 1.0
Distribution media is chosen as chambers, per Regulation Table l0-3,
Media:0.7
Then,
The minimum STA Area is 393.8 ft2.
450STA= 03 rL.0 x0.7
393.8Total Chambers =n
(1)
(2)
The minimum number of Quick 4 Plus Infiltrators is 32.8. As 32.8 Infiltrators cannot be evenly
divided between four trenches to ensure equal effluent flow, the design increases the number of
Quick 4 Plus Infiltrators to a total of 36, divided between four trenches with nine (9) units each.
8.0 SYSTEMINSTALLATIONREOUIREMENTS
The installer should confirm the feasibility of gravity discharge of sewage effluent from the
proposed residence to the STA. If field measurements do not confirm the design assumptions for
gravity discharge of sewage effluent from the proposed residence to the STA, or if the installer
does not consider the above design assumptions practical, please contact the design engineer to
address any design modifications necessary for the effective operation of the OWTS.
The installer must also confirm all setbacks from property lines, building envelopes, and existing
easements are maintained. Additionally, any unknown utility lines, easements, or other adverse
conditions disclosed during construction must maintain at the required minimum setbacks.
All sewer pipe couplings must be completed with primed and glued or bell and spigot joints
using 4-inch SDR 35 PVC pipe. Schedule 40 PVC 4-inch pipe with a minimum l-foot soil cover
must be used if pipe is installed in a vehicular traffic crossing. Drain-waste-vent (DWV) rated
Page 4
Schedule 40 PVC pipe is called out for crossings but may also be used instead of SDR 35 PVC
pipe.
One water line is proposed from the south face of the proposed single-family dwelling to the
existing water cistem. Per the Regulations, the septic tank must be setback a minimum of 50 feet
from the water cistern and all STA components must be setback a minimum of 100 feet from the
water cistern.
Building sewer pipe must be installed at a slope between ls-inch and %-inch per foot slope (l to
2Yo), preferably using the %-inch per foot slope as recommended by the International Plumbing
Code (IPC) as administered by the County. Fittings shall be sweep 90-degree curves or two (2)
45-degree elbows at all influent pipe turns. Fittings must be DWV for schedule 40 PVC pipe.
Two-way clean-outs are required between dwelling and tank and beyond tank where pipe lengths
exceed 100-feet from tank to STA and at all pipe bends greater than 45 degrees. Clean outs shall
be installed with screw caps at finished grade with a protective housing for easy access by
homeowner.
The installer must adhere to the minimum and maximum depth requirements for the STA.
System components must be placed on native soils or re-stabilized soils, as specified by the
engineered OWTS reports, in excavated areas.
The owner will ultimately be responsible for septic system maintenance including pumping the
septic tank once every 2-3 years and cleaning the effluent filter every 6 months.
9.0 SYSTEM INSPECTION
WestWater Engineering is responsible for inspecting the OWTS to ensure construction conforms
to the design plan and meets all aspects of County Regulations, including:
o Inspect and measure the system before backfilling, including piping and septic system
components.
Complete the as-built drawing of the system and submit it to Garfield County for
approval.
Reviewing and approving any submitted changes necessary for installation of the OWTS
as deemed necessary by the owner or their contractor. Any system changes installed by
the owner/contractor that were not approved by the Engineer are the responsibility of the
owner.
1O.O DESIGNLIMITATIONS
The OWTS design is based on site-specific soil conditions and percolation data collected in the
vicinity of the proposed STA, as well as local experience in designing OWTSs in Colorado. The
design is only valid for the proposed new OWTS serving the proposed 3-BR dwelling at the
referenced location provided in this report. WestWater Engineering assumes no liability for
inaccurate information or conditions that vary from the design assumptions listed above.
Additionally, WestWater Engineering is not responsible for the quality of work for any person(s)
or entity performing or supporting construction activities relating to the project, or for any
Page 5
a
a
contractor's failure to furnish or perform its work in accordance with the plans, specifications or
the Regulations. The owner/contractor is to notiff WestWater Engineering and/or Garfield
County immediately if actual site conditions differ from those described herein.
Please do not hesitate to contact us if you have any questions regarding this report.
Page 6
APPENDIX A
SOILS AND PERCOLATION DATA
QNest Water En g i neeri ng
-€ Consulting Engineers & Scientists
2516 FORESIGHT CIRCLE, #1 GRAND JUNCTION, COLORADO 81505 (97O) 241-7076 - FAX (970) 241-7097
SOILS AND PERCOLATION REPORT
Date July 16,2025
Consultant:Curtis Beckel, EIT
WestWater Engineering
2516 Foresight Circle #1
Grand Junction, CO 81505
(970) 241-7076
Client: Clayton Homes
Land Parcel: 146 Quicksilver Court, Rifle, CO 81650
2177-272-01-001
SECTION 1 _SOILS LOG
Two test pits were evaluated at the empty 1. 13-acre parcel for an onsite wastewater treatment
system (OWTS) that will serve a new proposed 3-BR single-family dwelling located at 146
Quicksilver Court, Rifle, Colorado.
The first Test Pit (TP-l) was located approximately 90 south of the north property line and 17
feet east of the west property line (see Figure B1 of the Design Report). The second Test pit (Tp-
2) was located approximately 10 feet north 5 feet east of TP-l. The benched test pits were in
general conformance with Figure Al with a maximum depth of 8 feet (96 inches) below ground
surface.
The visual description of the profile soils, with ASTM D 2488 "Standard Practice for
Description and Identification of Soils (Visual-Manual Procedures)" used for guidance, is
summarized below and in Table I - Log of Exploratory Test Pits. ASTM D 2488 identifies soils
based on visual examination and manual tests.
Table I - Log of Exploratory Test Pit 1
146 Quicksilver Court
Rifle, Colorado
Test Pit 1
Location: See Figure B-l Date:6-26-25
Depth
(f0 Description Interval
(f0 Notes
0
Stiff, dry, white, brown and tan,low plasticity,
silty sandy CLAY 0-l Topsoil
Stiff, dry, white and tan, low plasticity, sandy
SILT
Total Depth: 8 feet below ground surface
1-8
Scattered Gravels
Noted
5
146 Quicksilver Court
Rifle, Colorado
Test Pit 2
Location: See Figure B-1 Date:6-26-25
Depth
(f0 Description Interval
(f0 Notes
0
Stiff, dry, white, brown and tan, low plasticity,
silty sandy CLAY 0-1 Topsoil
Stifi dry, white andtan,low plasticity, sandy
SILT
Total Depth :4 feet below ground surface
1-4
Scattered Gravels
Noted
4
Table I - Log of Exploratory Test Pit 2
Subsurface conditions encountered in the test pits consisted of one foot of silty sandy clay topsoil
underlain by sandy silt to the maximum depth explored of 8 feet below ground surface, with
scattered gravels noted. The silty sandy clay topsoil was stiff, dry, white, brown and tan. The
sandy silt was stiff, dry, white and tan. No groundwater was encountered at the time of
observation.
SECTION 2 _ PERCOLATION TEST
Three standard percolation rate tests were performed at the site referenced.
TP-l contained 3 percolation test holes, approximately 1 foot in depth each, herein referred to as
P-I,P-2 and P-3. P-1 was located in TP-l at ground surface in silty, sandy clay topsoil. P-2 was
located in TP-l at 2 feet below ground surface in sandy silt. P-3 was located in TP-l at 4 feet
below ground surface in sandy silt. All percolation holes were saturated 24 hours before testing.
The percolation rates encountered were 1 1.9 minutes per inch in the silty, sandy clay topsoil at
the ground surface, I 1.4 minutes per inch in the sandy silt at 2 feet below ground surface, and
11.2 minutes per inch in the sandy silt at 4 feet below ground surface. WestWater Engineering
finds the average percolation rate of 11.5 most nearly describes the behavior of the soils at the
expected infiltration elevation of 3 feet below ground surface.
PERCOLATION TEST RESULTS
146 Quicksilver Court, Rifle
SATURATION AND PREPARATION
DATE: 6-25-25
PERCOLATION TEST
DATE: 6-26-25
HOLE REFERENCE NO: P-l
PERC HOLE DEPTH: Surface
TIME INTERVALS: 10 minutes
AVERAGE PERCOLATTON RATE (MIN/rNCH)tt.9
TIME AT
START OF
INTERVAL
START OF
INTERVAL
(rNCH)
END OF
INTERVAL
(rNCrr)
WATER
DEPTH
CHANGE
(INCH)
PERCOLATION
RATE
(MrN/rNCH)
1030 0 1 I 10
1040 1 2 I 10
10s0 2 J 1 10
I 100 J 3.75 0.75 13.33
1110 3.75 4.7s 1 l0
II2O 4.75 5.75 I 10
I 130 0 0.75 0.75 13.33
tr40 0.75 1.5 0.75 13.33
I ts0 1.5 2.2s 0.75 13.33
1200 2.25 aJ 0.7s 13.33
t2t0 J 3.75 0.75 13.33
1220 3.75 4.5 0.75 13.33
HOLE REFERENCE NO: P-2
PERC HOLE DEPTH: 2 feet
TIME INTERVALS: l0 minutes
HOLE REFERENCE NO: P-3
PERC HOLE DEPTH: 4 feet
TIME INTERVALS: 10 minutes
AVERAGE PERCOLATION RATE (MIN/INCH)tl.4
TIME AT
START OF
INTERVAL
START OF
INTERVAL
(rNCH)
END OF
INTERVAL
(rNCH)
WATER
DEPTH
CHANGE
(INCH)
PERCOLATION
RATE
(MrN/rNCH)
1030 0 1 I t0
1040 I 2 1 10
I 050 2 J I t0
1 100 J 4 1 10
1110 4 5 I 10
lt20 5 6 1 l0
I 130 0 1 I 10
1140 I 1.75 0.75 13.33
I 150 1.75 2.5 0.7s 13.33
1200 2.5 3.25 0.75 13.33
t2I0 3.25 4 0.75 13.33
1220 4 4.75 0.75 13.33
TIME AT
START OF
INTERVAL
START OF
INTERVAL
(rNCH)
END OF
INTERVAL
(rNcH)
WATER
DEPTH
CHANGE
(INCH)
PERCOLATION
RATE
(MrN/rNCH)
1030 0 t.2s t.25 8
1040 1.2s 2.5 t.2s 8
1050 2.5 3.75 l.2s 8
I 100 3.75 4.75 1 l0
1110 4.75 s.75 1 10
tl20 5.75 6.75 1 10
I 130 0 0.75 0.75 13.33
lt40 0.75 1.5 0.75 13.33
I 150 1.5 2.2s 0.75 t3.33
1200 2.25 J 0.75 13.33
l2I0 J 3.75 0.75 13.33
1220 3.75 4.5 0.7s 13.33
AVERAGE PERCOLATION RATE (MIN/INCH)ll.2
PERCOLATION TEST PIT
FIGURE 1
WestWoter
Engineering
2516 Foresight Circle, fl
Grond Junction, C0 81505
(s70) 241-7076
fI
=
SOILS AND PERCOLATION
TEST PIT SCHEMATIC
Profile View
EXISTING GROUND SURFACE HOLESURF
15'-----*1 15'
8'
Plon Mew
o
Cylindricol Percolotion
Test Holes 4-8" Diometer
1-Foot Deep
ou
+
7
___r
t
1 5
15'
P lotio Test P it Plon ew&c ross Sec tion
o
o
Scole 1"=10'
APPENDIX B
FIGURES
\
n\nhstVl/lter
2Engineering
2516 Foresight Circle, #l
Grand Junction, CO 81505
(970) 241-7076
www.westwaterco.com
goo,'/
EXISTING IPAVED SITE ACCESS
7
\
4 l
EXISTING DIRT SITE ACCESS
)
APPROXIMATE LOCATION
oF lESr Prr 2 (rP. 2)
APPROXIMATE LOCATION OF TEST PIT 1
(TP-1) CONTAINING PERCOI-ATION HOLES
1, 2, AND 3 (P-1, P-2, AND P-3)
-/-uuo
^-'
\ /\
----U----
APPROXIMATE LOCATION OF
EXISTING ELECTRICAL SERVICE
$
s\BEISNER, STEUE & TAMU
146 QUICKSTLVER COURT' 2(77-272-01-OOt
APPROXIMATE LOCATION OF'
EXISTING WATER CISTERN
\APPROXIMATE EXISTING PROPERTY LINE - 17.3
ACRES (een CARFIELD COTIJNTY cIS, JULY 2025)
200 100 0
SCALE: 1":2OO'
200 FIGURE 81
146 OUICKSILVER CT
DOSTING OWTS SITE PLAN
=
A\ilestVJhtet
2Engineering
2516 Foresight Circle, #l
Grand Junction, CO 8l 505
(970\ 24t-7o'.t6
www.westwate rco.com
APPROXIMATE EXISTING PROPERTY LINE - 17.3
AqRES (PER GARFIELD COUNTY GIS, JULY 2025)
FUTYR
s
nY
bt
EXISTING PAVED.
SITE ACCESS
E STA REPAIR AREA, 24'x39'
NEW INFILTRATOR TRENCHES,
4 TRENCHES 9 UNITS EACH,
36 TOTAL CHAMBER UNITS,
covER W/GEoTEXTTLE FABRIC 6' MIN(sEE FrcuRE 83)
IN
EXISTING DIRT
SITE ACCESS
NEW DISTRIBUTION
BOX U/FLOW C9NTROL
PROPOSED NEW 1,OOO NEW 4,, SDR 35 PVC
SEWER SERVICE
(L:7e.4 L.F.t,S=2%)
GALLON SEPTIC TANK
5, MIN
PROPOSED 3_BR APPROXIMATE
LOCATION OF TP_2DWELLING
APPROXIMATE
LOCATION OF TP_1
PROPOSED
WATER SERVICE
NEW 2_WAY CLEANOUT
APPROXIMATE LOCATION OF
EXISTING ELECTRICAL SERVICE
1OO, MIN SFTBACK
FROM CISTERN TO STA
50, MIN SIIBACK FROM
CISTERN TO SEPTIC TANK
APPROXIMATE LOCATION OF
EXISTING WATER CISTERN
60300
SCALE: 1":60'
60 FIGURE 82
146 QUICKSILVER COURT
PROPOSED OTVTS I.AY-OUT
FIGURE 83
146 OUICKSILVER COURT
OWTS CROSS SECTION
Arfihstlfl/'htnr
2Engineering
25 I 6 Foresight Circle, #l
Grand Junction, CO 8 I 505
(970) 24t-7076
www.westwaterco.com
PORT WITH CAP
APPROXIMATE EXISTING
NEW 4'SCH 40 PVC OBSERVATION
NEW 10" ROUND IRRIGATION
VALVE BOX AT FACH PORT
MOUNTED FLUSH WITH GROUN
8.0'
Y GROUNDWATER
GREATER THAN 8.0'
PLACE GEOTEXTTLE (2 OZ/yf) Ovrn TNFTLTRATORS (ryp)
CROWN BACKFILL OVER TRENCHES
o
+
o
@
TRENCH NOTE:
MAXIMUM DEPTH 4.0 FETT
MINIMUM DEPTH 3.0 FEET
INSTALI.ATION NOTES:
1) FOLLOW MANUFACTURERS INSTRUCTION www.infittrotorsystems.com2) SCREW pIpE TOp PORT CHAMBER FACEP|-ATE3) SCREW FACEPI-ATES AND UNITS TOGEIHER4) INSTALL MONITORING PORTS TRENCH ENDS
ALL FOUR BED CORNERS
36 Q4 INFILTRATORS
(4) TRENCHES
(s) uruns EAcH TRENcH
PROVIDE LEVEL SCARIFIED SURFACE
ACROSS LENGTH OF TRENCH(S), NOTIFy
ENGTNEER rF TRENCH BOTTOM(S) ARE WEr
SCALE 1"=5'
4.O'4.0'4.O'
TOPSOIL
FJ
a
Oz
a
FIGURE 84
146 OUICKSILVER COURT
1,000 GALLON SEffiC TAl.tK
A\lrhstUf|iltprr
2Engineering
2516 Foresight Circle, #1
Grand Juction, CO 81505
(970) 24r-7076
ww.westwaterco.com
NW,l 24"A ACCESS
HATCHES WITH LOCK
SECURE TANK LIDS
rNG/
FINISHED GRADE
NATIVE BACKFILL COMPATEDro 95% MSHTO r-99 +.2%
OPTIMUM SOIL MOISTURE oRENCO (On EOUWALENT)
4" EFFLUENT FILTER
GMVITYFLowFRoMDWELLING+
NEW 4" SCH 40 PVC
SEWER LINE
(L:70.4'*, S:-Z%)
TO STA
NEW 4,' SCH 40
PVC SEWER LINE
DISTRIBUTION BOX
NEW 4" SCH 40 PVC WYE^EE
NEW 1,OOO GALLON SEPTIC TANK
NEW 7+" MINUS WASHED RocK
z
4
x
+
HWL 4,AFF
?e
N
N
lf)
(8" rNCH DEPTH MTNIMUM)
APPENDIX C
GARFIELD COUNTY ON-SITE WASTE WATER
TREATMENT SYSTEM REGULATIONS, TABLE
7-1 FROM THE 2OI9 REGULATION DOCUMENT
CODE OF COLORADO REGULATION
Water Quality Control Commission
5 CCR 1002-43
Table 7-1 Minimum Horizontal Distances in Feet Between Components of an On-Site Wastewater Treatment System Installed After
November 1 1973 and Water and Health Features
5
5
5
Septic
Tank,
Higher level
treatment
Unit,
Dosing
Tank, Vault
or Privy
102
25
10
10
Dry
Gulch,
Cut
Bank,
Fiil
Area
(from
Crest)
10
25
25
50
502
503
Lake,
Water
Course,
lrrigation
Ditch,
Stream,
Wetland
25
10
10
10
102
Subsurface
Drain,
lntermittent
lrrigation
Lateral,
Drywell,
Stormwater
Structure
102
10
10
01
Property
Lines,
Piped or
Lined
lrrigation
Ditch,
upslope
curtain
drain
10
0
10
10
15
5
Structure
without
basement,
crawl
space or
footing
drains
5
0
20
15
15
Structure
w/basement,
crawl space
or footing
drains
56
252
102
102
Potable
Water
Supply
Line 2
102
502
100 3
60
60
Spring,
Well,1
Suction
Line,
Potable
Water
Supply
Cisterna
502Septic Tank,
Higher Level
Treatment Unit,
Dosing Tank,
Vault or Vault
Priw
Building Sewer or
Effluent Lines
STA Trench, STA
Bed, Unlined
Sand Filter, Sub-
surface Dispersal
System, Seepage
Pit
Lined Sand Filter
Lined Evapo-
transpiration Field
or Outside of
Berm of Lined
Wastewater Pond
43
FIG. C-1
Septic
Tank,
Higher level
treatment
Unit,
Dosing
Tank, Vault
or Privy
1 0
N/A
10
Dry
Gulch,
Cut
Bank,
Fiil
Area
(from
Crest)
15
25
10
Lake,
Water
Course,
lrrigation
Ditch,
Stream,
Wetland
25
100
253
Subsurface
Drain,
lntermittent
lrrigation
Lateral,
Drywell,
Stormwater
Structure
25
25
0
Property
Lines,
Piped or
Lined
lrrigation
Ditch,
upslope
curtain
drain
10
25
1 0
Structure
without
basement,
crawl
space or
footing
drains
15
25
125s
Structure
w/basement,
crawl space
or footing
drains
15
25
125
Potable
Water
Supply
Line 2
252
502
102
Spring,
Well,l
Suction
Line,
Potable
Water
Supply
Cisterna
100
100
100 3
Unlined Sand
Filter in SoilWith
a Percolation Rate
Slower than 60
Minutes per lnch,
Unlined or
Partially Lined
Evapotrans-
piration System,
Outside of Berm
of Unlined
Wastewater Pond,
or System Not
Relying on STA
for Treatment
Other than
Aerosol
Slit Trench
Latrine, Pit Priw
System Not
Relying on STA
for Dispersal
CODE OF COLORADO REGULATION 5 CCR 1002-43
Water Quality Control Commission
NOTE: The minimum distances shown above must be maintained between the OWTS components and the features described. Where soil, geological or other conditions warrant,
or upgrading of existing OWTS where the size of lot precludes adherence to these diitances, a repaired OWTS must not be closer to setback features ihan the
"*iiting OWTS, asreviewed and approved by the local public health agency. Components that are not watertight should not extend into areas of the root system of nearby trees.
1 lncludes potable wells, irrigation wells and monitoring wells set within a potable aquifer and infiltration galleries permifted as wells by the Division of Water Resources.
4
FtG. C-2
CODE OF COLORADO REGIILATION
Water Quality Control Commission
5 CCR 1002-43
2 Crossings or encroachments may be permifted at the points as noted above provided that the water or wastewater conveyance pipe is encased for the minimum setbackdistance on each side of the crossing. A length of pipe with a minimum Schedule 40 rating [ASTM Standard D 3034-16 (2016 version)] of sufiicient diameter to easily slide over andcompletely encase the conveyance must be used. Rigid end caps of at least schedule +o'riting [ASTM standard D 3034-1 6 (2016 version) must be glued or secured in a watertight
the bottom of the encasement pipe. The area in which the pipe passes through the end caps must be sealed with an approved underground sealant compatible with the piping used.Other methods of encasement that provide equal protection are allowed. Thdse methods must be reviewed and approved by the local public health agency.
3 Add eight feet additional distance for each 100 g-allons per day of design flows between 1 ,000 and 2,000 gallons per day, unless it can be demonstrated by a professional
required to minimize contamination as part of the Division site ipplication and permitting procl"s.
4 All horizontal setbacks to- a potable water supply cistem must be met unless a variance by the Board of Examiners of Water Well construction and pump lnstallation
1 1 '4 of the Water Well Construction Rules, as applicable. The minimum horizontal setback that may be jranted througn a variance is to 25 feet.
5 lf the structure is not used as a habitable unit, the isolation may be reduced by the local board of health to no less than S0 feet.
6. Building sewer installations shall meet the design requirements of the Colorado plumbing Code.
45
FrG. C-3