Sewer Maintenance Worker Exam
Practice Questions and Correct Answers
(Verified Answers) Plus Rationale 2026
Q&A| Instant Download Pdf
Sewer System Fundamentals
1. Gravity Sewer Function
What is the primary purpose of a sanitary sewer collection system?
A. Store drinking water
B. Collect and convey wastewater to a treatment facility
C. Supply water to fire hydrants
D. Control roadway traffic
Correct Answer: B. Collect and convey wastewater to a treatment facility
Rationale: A sanitary sewer collection system receives wastewater from homes,
businesses, and other sources and conveys it toward a wastewater treatment
facility or other authorized destination.
2. Gravity Flow
What causes wastewater to flow through a properly designed gravity sewer?
A. Elevation difference
B. Compressed air
C. Mechanical pumps in every pipe
D. Atmospheric pressure alone
Correct Answer: A. Elevation difference
,Rationale: Gravity sewers rely primarily on differences in elevation to move
wastewater through the collection system. Proper pipe slope helps maintain the
intended flow.
3. Sewer Slope
Why is adequate slope important in a gravity sewer?
A. It helps maintain wastewater movement and reduces solids deposition
B. It increases pipe color stability
C. It eliminates the need for maintenance
D. It prevents all inflow
Correct Answer: A. It helps maintain wastewater movement and reduces solids
deposition
Rationale: Adequate slope helps wastewater flow at an appropriate velocity.
Insufficient slope can contribute to low flow velocities and accumulation of solids.
4. Sanitary Sewer
What is normally conveyed by a sanitary sewer?
A. Stormwater from road surfaces only
B. Domestic and commercial wastewater
C. Drinking water
D. Natural gas
Correct Answer: B. Domestic and commercial wastewater
Rationale: Sanitary sewers are designed primarily to convey wastewater
generated by residences, businesses, institutions, and similar sources.
5. Storm Sewer
What is the primary function of a storm sewer?
,A. Convey stormwater runoff
B. Transport sewage to a treatment plant
C. Supply potable water
D. Transport natural gas
Correct Answer: A. Convey stormwater runoff
Rationale: Storm sewer systems collect and convey precipitation and surface
runoff. They are distinct from sanitary sewer systems, although some older
systems may combine the two.
6. Combined Sewer
What does a combined sewer system convey?
A. Drinking water and wastewater
B. Sanitary wastewater and stormwater in the same system
C. Only industrial wastewater
D. Only groundwater
Correct Answer: B. Sanitary wastewater and stormwater in the same system
Rationale: Combined sewer systems are designed to carry both sanitary sewage
and stormwater. During heavy rainfall, they may experience significantly
increased flows.
7. Sewer Main
What is a sewer main?
A. A primary pipe that collects and conveys wastewater from connected service
lines
B. A water-storage tank
C. A storm drain grate
D. A treatment plant laboratory
Correct Answer: A. A primary pipe that collects and conveys wastewater from
connected service lines
, Rationale: Sewer mains form the primary network of collection pipes. Smaller
lateral or service connections typically discharge into the main.
8. Sewer Lateral
What is a sewer lateral?
A. A connection carrying wastewater between a property and the public sewer
system
B. A treatment plant pump
C. A stormwater detention pond
D. A manhole cover
Correct Answer: A. A connection carrying wastewater between a property and
the public sewer system
Rationale: A sewer lateral generally connects a building or property to the public
sewer main. Ownership and maintenance responsibility vary by jurisdiction.
9. Infiltration
What is infiltration in a sewer collection system?
A. Entry of groundwater through defects or openings in the sewer system
B. Intentional addition of drinking water
C. Discharge of sewage from a treatment plant
D. Flow of wastewater caused by a pump
Correct Answer: A. Entry of groundwater through defects or openings in the
sewer system
Rationale: Groundwater can enter through cracks, defective joints, broken pipes,
manholes, or other openings below the groundwater table.
10. Inflow
What is inflow in a sanitary sewer system?
Practice Questions and Correct Answers
(Verified Answers) Plus Rationale 2026
Q&A| Instant Download Pdf
Sewer System Fundamentals
1. Gravity Sewer Function
What is the primary purpose of a sanitary sewer collection system?
A. Store drinking water
B. Collect and convey wastewater to a treatment facility
C. Supply water to fire hydrants
D. Control roadway traffic
Correct Answer: B. Collect and convey wastewater to a treatment facility
Rationale: A sanitary sewer collection system receives wastewater from homes,
businesses, and other sources and conveys it toward a wastewater treatment
facility or other authorized destination.
2. Gravity Flow
What causes wastewater to flow through a properly designed gravity sewer?
A. Elevation difference
B. Compressed air
C. Mechanical pumps in every pipe
D. Atmospheric pressure alone
Correct Answer: A. Elevation difference
,Rationale: Gravity sewers rely primarily on differences in elevation to move
wastewater through the collection system. Proper pipe slope helps maintain the
intended flow.
3. Sewer Slope
Why is adequate slope important in a gravity sewer?
A. It helps maintain wastewater movement and reduces solids deposition
B. It increases pipe color stability
C. It eliminates the need for maintenance
D. It prevents all inflow
Correct Answer: A. It helps maintain wastewater movement and reduces solids
deposition
Rationale: Adequate slope helps wastewater flow at an appropriate velocity.
Insufficient slope can contribute to low flow velocities and accumulation of solids.
4. Sanitary Sewer
What is normally conveyed by a sanitary sewer?
A. Stormwater from road surfaces only
B. Domestic and commercial wastewater
C. Drinking water
D. Natural gas
Correct Answer: B. Domestic and commercial wastewater
Rationale: Sanitary sewers are designed primarily to convey wastewater
generated by residences, businesses, institutions, and similar sources.
5. Storm Sewer
What is the primary function of a storm sewer?
,A. Convey stormwater runoff
B. Transport sewage to a treatment plant
C. Supply potable water
D. Transport natural gas
Correct Answer: A. Convey stormwater runoff
Rationale: Storm sewer systems collect and convey precipitation and surface
runoff. They are distinct from sanitary sewer systems, although some older
systems may combine the two.
6. Combined Sewer
What does a combined sewer system convey?
A. Drinking water and wastewater
B. Sanitary wastewater and stormwater in the same system
C. Only industrial wastewater
D. Only groundwater
Correct Answer: B. Sanitary wastewater and stormwater in the same system
Rationale: Combined sewer systems are designed to carry both sanitary sewage
and stormwater. During heavy rainfall, they may experience significantly
increased flows.
7. Sewer Main
What is a sewer main?
A. A primary pipe that collects and conveys wastewater from connected service
lines
B. A water-storage tank
C. A storm drain grate
D. A treatment plant laboratory
Correct Answer: A. A primary pipe that collects and conveys wastewater from
connected service lines
, Rationale: Sewer mains form the primary network of collection pipes. Smaller
lateral or service connections typically discharge into the main.
8. Sewer Lateral
What is a sewer lateral?
A. A connection carrying wastewater between a property and the public sewer
system
B. A treatment plant pump
C. A stormwater detention pond
D. A manhole cover
Correct Answer: A. A connection carrying wastewater between a property and
the public sewer system
Rationale: A sewer lateral generally connects a building or property to the public
sewer main. Ownership and maintenance responsibility vary by jurisdiction.
9. Infiltration
What is infiltration in a sewer collection system?
A. Entry of groundwater through defects or openings in the sewer system
B. Intentional addition of drinking water
C. Discharge of sewage from a treatment plant
D. Flow of wastewater caused by a pump
Correct Answer: A. Entry of groundwater through defects or openings in the
sewer system
Rationale: Groundwater can enter through cracks, defective joints, broken pipes,
manholes, or other openings below the groundwater table.
10. Inflow
What is inflow in a sanitary sewer system?
