CWEA COLLECTION SYSTEMS MAINTENANCE
EXAM STUDY GUIDE 2026/2027 | COMPLETE
QUESTIONS BANK & VERIFIED ANSWERS WITH
RATIONALES | WASTEWATER CERTIFICATION
PREP
• This study guide provides comprehensive exam preparation for the CWEA
Collection Systems Maintenance certification, featuring verified questions with
highlighted correct answers and detailed EXPERT RATIONALE to reinforce
understanding.
• Each question follows a structured format with five options (A–E), a clearly
marked correct answer, and an explanation — making it easy to study, self-test, and
retain key concepts for exam day.
1. What is the primary purpose of a collection system in wastewater
management?
A. To treat wastewater before discharge
B. To supply drinking water to residents
C. To collect and convey wastewater from homes and businesses to treatment
facilities
D. To manage stormwater runoff only
E. To recycle water for industrial use
Correct Answer: C. To collect and convey wastewater from homes and
businesses to treatment facilities
EXPERT RATIONALE: A collection system's primary function is to gather sewage
and wastewater from residential, commercial, and industrial sources and transport
it safely to a wastewater treatment plant for processing.
2. Which type of sewer carries both sanitary sewage and stormwater runoff in
the same pipe?
,A. Sanitary sewer
B. Force main
C. Combined sewer
D. Interceptor sewer
E. Gravity sewer
Correct Answer: C. Combined sewer
EXPERT RATIONALE: Combined sewers are designed to carry both sanitary
sewage and stormwater in a single pipe system. During heavy rainfall, they can
overflow, causing combined sewer overflows (CSOs), which is an environmental
concern.
3. What does the term "inflow and infiltration" (I/I) refer to in collection
systems?
A. The flow of treated water back into the system
B. The process of cleaning sewer pipes
C. Stormwater and groundwater entering the sanitary sewer system
D. The pumping of sewage to higher elevations
E. The measurement of sewage flow rates
Correct Answer: C. Stormwater and groundwater entering the sanitary sewer
system
EXPERT RATIONALE: Inflow refers to stormwater entering the system through
direct connections such as roof drains or catch basins. Infiltration is groundwater
seeping through cracks, joints, or deteriorated pipe materials. Both increase system
load unnecessarily.
4. What is a manhole primarily used for in a collection system?
,A. To measure sewage flow
B. To pump sewage uphill
C. To provide access to underground sewer pipes for inspection and
maintenance
D. To store wastewater temporarily
E. To release excess pressure from the system
Correct Answer: C. To provide access to underground sewer pipes for inspection
and maintenance
EXPERT RATIONALE: Manholes are access structures placed at intervals along
sewer lines to allow workers to inspect, clean, repair, and maintain underground
pipelines safely and efficiently.
5. Which pipe material is most commonly used in modern sewer construction
due to its resistance to corrosion?
A. Cast iron
B. Concrete
C. PVC (Polyvinyl Chloride)
D. Clay tile
E. Copper
Correct Answer: C. PVC (Polyvinyl Chloride)
EXPERT RATIONALE: PVC is widely used in modern sewer construction because
of its excellent resistance to corrosion, smooth interior surface that reduces
friction, lightweight nature, and ease of installation compared to older materials like
clay or concrete.
6. What is the minimum slope recommended for an 8-inch diameter sewer
pipe to maintain self-cleansing velocity?
, A. 0.10%
B. 0.20%
C. 0.40%
D. 1.00%
E. 2.00%
Correct Answer: C. 0.40%
EXPERT RATIONALE: An 8-inch sewer pipe requires a minimum slope of
approximately 0.40% (0.4 feet per 100 feet) to achieve a self-cleansing velocity of at
least 2 feet per second, which prevents solids from settling in the pipe.
7. What is the self-cleansing velocity in a sewer pipe?
A. 0.5 ft/s
B. 1.0 ft/s
C. 2.0 ft/s
D. 3.5 ft/s
E. 5.0 ft/s
Correct Answer: C. 2.0 ft/s
EXPERT RATIONALE: A minimum velocity of 2.0 feet per second is required to
keep solids in suspension and prevent deposition within the sewer pipe. This is
called the self-cleansing velocity and is critical for maintaining proper flow
conditions.
8. Which type of sewer flow relies solely on gravity to move wastewater?
A. Force main
B. Pressure sewer
EXAM STUDY GUIDE 2026/2027 | COMPLETE
QUESTIONS BANK & VERIFIED ANSWERS WITH
RATIONALES | WASTEWATER CERTIFICATION
PREP
• This study guide provides comprehensive exam preparation for the CWEA
Collection Systems Maintenance certification, featuring verified questions with
highlighted correct answers and detailed EXPERT RATIONALE to reinforce
understanding.
• Each question follows a structured format with five options (A–E), a clearly
marked correct answer, and an explanation — making it easy to study, self-test, and
retain key concepts for exam day.
1. What is the primary purpose of a collection system in wastewater
management?
A. To treat wastewater before discharge
B. To supply drinking water to residents
C. To collect and convey wastewater from homes and businesses to treatment
facilities
D. To manage stormwater runoff only
E. To recycle water for industrial use
Correct Answer: C. To collect and convey wastewater from homes and
businesses to treatment facilities
EXPERT RATIONALE: A collection system's primary function is to gather sewage
and wastewater from residential, commercial, and industrial sources and transport
it safely to a wastewater treatment plant for processing.
2. Which type of sewer carries both sanitary sewage and stormwater runoff in
the same pipe?
,A. Sanitary sewer
B. Force main
C. Combined sewer
D. Interceptor sewer
E. Gravity sewer
Correct Answer: C. Combined sewer
EXPERT RATIONALE: Combined sewers are designed to carry both sanitary
sewage and stormwater in a single pipe system. During heavy rainfall, they can
overflow, causing combined sewer overflows (CSOs), which is an environmental
concern.
3. What does the term "inflow and infiltration" (I/I) refer to in collection
systems?
A. The flow of treated water back into the system
B. The process of cleaning sewer pipes
C. Stormwater and groundwater entering the sanitary sewer system
D. The pumping of sewage to higher elevations
E. The measurement of sewage flow rates
Correct Answer: C. Stormwater and groundwater entering the sanitary sewer
system
EXPERT RATIONALE: Inflow refers to stormwater entering the system through
direct connections such as roof drains or catch basins. Infiltration is groundwater
seeping through cracks, joints, or deteriorated pipe materials. Both increase system
load unnecessarily.
4. What is a manhole primarily used for in a collection system?
,A. To measure sewage flow
B. To pump sewage uphill
C. To provide access to underground sewer pipes for inspection and
maintenance
D. To store wastewater temporarily
E. To release excess pressure from the system
Correct Answer: C. To provide access to underground sewer pipes for inspection
and maintenance
EXPERT RATIONALE: Manholes are access structures placed at intervals along
sewer lines to allow workers to inspect, clean, repair, and maintain underground
pipelines safely and efficiently.
5. Which pipe material is most commonly used in modern sewer construction
due to its resistance to corrosion?
A. Cast iron
B. Concrete
C. PVC (Polyvinyl Chloride)
D. Clay tile
E. Copper
Correct Answer: C. PVC (Polyvinyl Chloride)
EXPERT RATIONALE: PVC is widely used in modern sewer construction because
of its excellent resistance to corrosion, smooth interior surface that reduces
friction, lightweight nature, and ease of installation compared to older materials like
clay or concrete.
6. What is the minimum slope recommended for an 8-inch diameter sewer
pipe to maintain self-cleansing velocity?
, A. 0.10%
B. 0.20%
C. 0.40%
D. 1.00%
E. 2.00%
Correct Answer: C. 0.40%
EXPERT RATIONALE: An 8-inch sewer pipe requires a minimum slope of
approximately 0.40% (0.4 feet per 100 feet) to achieve a self-cleansing velocity of at
least 2 feet per second, which prevents solids from settling in the pipe.
7. What is the self-cleansing velocity in a sewer pipe?
A. 0.5 ft/s
B. 1.0 ft/s
C. 2.0 ft/s
D. 3.5 ft/s
E. 5.0 ft/s
Correct Answer: C. 2.0 ft/s
EXPERT RATIONALE: A minimum velocity of 2.0 feet per second is required to
keep solids in suspension and prevent deposition within the sewer pipe. This is
called the self-cleansing velocity and is critical for maintaining proper flow
conditions.
8. Which type of sewer flow relies solely on gravity to move wastewater?
A. Force main
B. Pressure sewer
