CO Septic System Installer Exam
Practice Questions And Correct
Answers (Verified Answers) Plus
Rationale 2027 Q&A| Instant
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1. Which statement best describes an onsite wastewater treatment
system (OWTS) under Colorado requirements?
A. A centralized municipal wastewater collection system serving an entire
city
B. A stormwater drainage system designed to remove surface runoff
C. A system designed to treat, neutralize, stabilize, store, or dispose of
sewage without being part of a centralized sewage collection system
D. A potable-water distribution system serving an individual residence
An OWTS is a decentralized wastewater system whose components treat
or dispose of sewage without being connected to a centralized collection
and treatment system.
2. Which Colorado agency has primary statewide responsibility for
establishing requirements for onsite wastewater treatment
systems?
A. Colorado Department of Transportation
B. Colorado Division of Fire Prevention and Control
,C. Colorado Department of Agriculture
D. Colorado Department of Public Health and Environment (CDPHE)
CDPHE establishes statewide public-health and environmental
requirements governing onsite wastewater treatment systems, while
local agencies may administer permitting and enforcement within their
jurisdictions.
3. What is the primary purpose of a septic tank in a conventional
OWTS?
A. To disinfect wastewater completely before discharge
B. To increase groundwater infiltration
C. To provide settling, flotation, and anaerobic treatment before effluent
enters the soil treatment area
D. To pump sewage directly into groundwater
A septic tank separates solids and floatable materials from wastewater
and provides initial biological treatment before clarified effluent is
distributed to the soil treatment area.
4. What is the principal function of the soil treatment area in a
conventional septic system?
A. To store all wastewater permanently
B. To increase sewage temperature
C. To remove only large solids from sewage
D. To receive effluent and provide treatment and dispersal through soil
,The soil treatment area provides both hydraulic dispersal and additional
physical, chemical, and biological treatment of septic tank effluent.
5. Before installing an OWTS, what site characteristic is particularly
important to evaluate?
A. Color of nearby buildings
B. Soil characteristics and limiting conditions such as groundwater,
bedrock, and restrictive layers
C. Number of vehicles owned by the property owner
D. Type of interior floor covering
Soil and subsurface conditions determine whether the site can
adequately treat and disperse wastewater while protecting
groundwater and surface water.
6. Why is groundwater separation important when designing a soil
treatment area?
A. Groundwater improves septic tank digestion
B. Groundwater eliminates the need for soil treatment
C. Adequate separation helps provide sufficient unsaturated soil for
wastewater treatment and protects groundwater quality
D. Groundwater prevents all hydraulic failures
Unsaturated soil provides important treatment capacity, so insufficient
separation between the infiltrative surface and groundwater can impair
treatment and increase contamination risk.
, 7. Which soil characteristic most directly affects the rate at which
effluent can infiltrate?
A. Soil color alone
B. Organic odor
C. Soil texture, structure, and hydraulic conductivity
D. Vegetation height alone
The physical characteristics of soil control its ability to accept, transmit,
and treat septic effluent.
8. What is the primary concern with placing a septic system in highly
restrictive soil?
A. Excessive oxygen production
B. Inadequate infiltration and possible wastewater surfacing or hydraulic
failure
C. Increased potable-water pressure
D. Excessive septic tank ventilation
Restrictive soils may not accept wastewater rapidly enough, causing
ponding, surfacing effluent, or premature system failure.
9. Why should roof gutters generally be directed away from a soil
treatment area?
A. Roof water increases septic tank bacterial activity
B. Additional stormwater can hydraulically overload the soil treatment
area
Practice Questions And Correct
Answers (Verified Answers) Plus
Rationale 2027 Q&A| Instant
Download Pdf.
1. Which statement best describes an onsite wastewater treatment
system (OWTS) under Colorado requirements?
A. A centralized municipal wastewater collection system serving an entire
city
B. A stormwater drainage system designed to remove surface runoff
C. A system designed to treat, neutralize, stabilize, store, or dispose of
sewage without being part of a centralized sewage collection system
D. A potable-water distribution system serving an individual residence
An OWTS is a decentralized wastewater system whose components treat
or dispose of sewage without being connected to a centralized collection
and treatment system.
2. Which Colorado agency has primary statewide responsibility for
establishing requirements for onsite wastewater treatment
systems?
A. Colorado Department of Transportation
B. Colorado Division of Fire Prevention and Control
,C. Colorado Department of Agriculture
D. Colorado Department of Public Health and Environment (CDPHE)
CDPHE establishes statewide public-health and environmental
requirements governing onsite wastewater treatment systems, while
local agencies may administer permitting and enforcement within their
jurisdictions.
3. What is the primary purpose of a septic tank in a conventional
OWTS?
A. To disinfect wastewater completely before discharge
B. To increase groundwater infiltration
C. To provide settling, flotation, and anaerobic treatment before effluent
enters the soil treatment area
D. To pump sewage directly into groundwater
A septic tank separates solids and floatable materials from wastewater
and provides initial biological treatment before clarified effluent is
distributed to the soil treatment area.
4. What is the principal function of the soil treatment area in a
conventional septic system?
A. To store all wastewater permanently
B. To increase sewage temperature
C. To remove only large solids from sewage
D. To receive effluent and provide treatment and dispersal through soil
,The soil treatment area provides both hydraulic dispersal and additional
physical, chemical, and biological treatment of septic tank effluent.
5. Before installing an OWTS, what site characteristic is particularly
important to evaluate?
A. Color of nearby buildings
B. Soil characteristics and limiting conditions such as groundwater,
bedrock, and restrictive layers
C. Number of vehicles owned by the property owner
D. Type of interior floor covering
Soil and subsurface conditions determine whether the site can
adequately treat and disperse wastewater while protecting
groundwater and surface water.
6. Why is groundwater separation important when designing a soil
treatment area?
A. Groundwater improves septic tank digestion
B. Groundwater eliminates the need for soil treatment
C. Adequate separation helps provide sufficient unsaturated soil for
wastewater treatment and protects groundwater quality
D. Groundwater prevents all hydraulic failures
Unsaturated soil provides important treatment capacity, so insufficient
separation between the infiltrative surface and groundwater can impair
treatment and increase contamination risk.
, 7. Which soil characteristic most directly affects the rate at which
effluent can infiltrate?
A. Soil color alone
B. Organic odor
C. Soil texture, structure, and hydraulic conductivity
D. Vegetation height alone
The physical characteristics of soil control its ability to accept, transmit,
and treat septic effluent.
8. What is the primary concern with placing a septic system in highly
restrictive soil?
A. Excessive oxygen production
B. Inadequate infiltration and possible wastewater surfacing or hydraulic
failure
C. Increased potable-water pressure
D. Excessive septic tank ventilation
Restrictive soils may not accept wastewater rapidly enough, causing
ponding, surfacing effluent, or premature system failure.
9. Why should roof gutters generally be directed away from a soil
treatment area?
A. Roof water increases septic tank bacterial activity
B. Additional stormwater can hydraulically overload the soil treatment
area
