AR SS Sewer & Sanitation
Contractor Exam Questions
and Correct Answers (Verified
Answers) Plus Rationale 2027
Q&A| Instant Download Pdf
1. What is the primary purpose of a sanitary sewer system?
A. To collect and distribute drinking water
B. To collect and convey wastewater to a treatment facility
C. To transport stormwater exclusively
D. To provide groundwater recharge
,Rationale: A sanitary sewer system collects wastewater from
residential, commercial, and industrial sources and conveys it to a
wastewater treatment facility or other approved treatment system.
Proper collection and treatment help protect public health, prevent
environmental contamination, and maintain sanitation.
2. Which type of sewer system is specifically designed to carry
domestic and industrial wastewater?
A. Storm sewer
B. Irrigation drainage system
C. Sanitary sewer
D. Roof drainage system
Rationale: Sanitary sewers transport wastewater generated by toilets,
sinks, showers, commercial operations, and approved industrial
discharges. Storm sewers are designed primarily for rainwater and
surface runoff. Keeping these systems properly separated helps
prevent wastewater overflows and treatment plant overloading.
3. What is the primary function of a sewer manhole?
A. To increase the chemical treatment of wastewater
B. To provide drinking water storage
,C. To provide access for inspection, cleaning, and maintenance
D. To eliminate the need for sewer pipe joints
Rationale: Manholes provide access to underground sewer
infrastructure for inspection, maintenance, cleaning, and certain
repairs. They are commonly installed at changes in direction, grade,
pipe size, or at specified intervals along a sewer line.
4. What does the term “invert elevation” refer to in sewer
construction?
A. The elevation of the top of the pipe
B. The elevation of the inside bottom of the pipe
C. The elevation of the surrounding ground
D. The elevation of the manhole cover
Rationale: The invert elevation is the vertical elevation of the lowest
interior surface of a pipe or channel. Contractors use invert elevations
to establish sewer grades, coordinate connections, and maintain the
designed flow path. Incorrect invert elevations can cause ponding,
inadequate cover, or improper connections.
5. What is the primary purpose of providing a continuous slope in a
gravity sewer?
, A. To increase the diameter of the pipe
B. To eliminate the need for manholes
C. To allow wastewater to flow by gravity
D. To prevent all solids from entering the sewer
Rationale: Gravity sewers are installed at designed slopes so
wastewater flows from higher elevations toward lower elevations
without continuous pumping. The specified grade must account for
pipe size, flow conditions, project requirements, and applicable design
standards.
6. What is meant by “infiltration” in a sanitary sewer system?
A. Wastewater escaping through a pipe joint
B. Groundwater entering the sewer through defects or openings
C. Rainwater flowing across a paved road
D. Air entering a ventilation stack from the roof
Rationale: Infiltration occurs when groundwater enters a sewer
through cracks, defective joints, damaged manholes, or other
openings. Excessive infiltration can increase treatment costs, overload
collection systems, and contribute to sanitary sewer overflows.
7. What is “exfiltration” in sewer construction?
Contractor Exam Questions
and Correct Answers (Verified
Answers) Plus Rationale 2027
Q&A| Instant Download Pdf
1. What is the primary purpose of a sanitary sewer system?
A. To collect and distribute drinking water
B. To collect and convey wastewater to a treatment facility
C. To transport stormwater exclusively
D. To provide groundwater recharge
,Rationale: A sanitary sewer system collects wastewater from
residential, commercial, and industrial sources and conveys it to a
wastewater treatment facility or other approved treatment system.
Proper collection and treatment help protect public health, prevent
environmental contamination, and maintain sanitation.
2. Which type of sewer system is specifically designed to carry
domestic and industrial wastewater?
A. Storm sewer
B. Irrigation drainage system
C. Sanitary sewer
D. Roof drainage system
Rationale: Sanitary sewers transport wastewater generated by toilets,
sinks, showers, commercial operations, and approved industrial
discharges. Storm sewers are designed primarily for rainwater and
surface runoff. Keeping these systems properly separated helps
prevent wastewater overflows and treatment plant overloading.
3. What is the primary function of a sewer manhole?
A. To increase the chemical treatment of wastewater
B. To provide drinking water storage
,C. To provide access for inspection, cleaning, and maintenance
D. To eliminate the need for sewer pipe joints
Rationale: Manholes provide access to underground sewer
infrastructure for inspection, maintenance, cleaning, and certain
repairs. They are commonly installed at changes in direction, grade,
pipe size, or at specified intervals along a sewer line.
4. What does the term “invert elevation” refer to in sewer
construction?
A. The elevation of the top of the pipe
B. The elevation of the inside bottom of the pipe
C. The elevation of the surrounding ground
D. The elevation of the manhole cover
Rationale: The invert elevation is the vertical elevation of the lowest
interior surface of a pipe or channel. Contractors use invert elevations
to establish sewer grades, coordinate connections, and maintain the
designed flow path. Incorrect invert elevations can cause ponding,
inadequate cover, or improper connections.
5. What is the primary purpose of providing a continuous slope in a
gravity sewer?
, A. To increase the diameter of the pipe
B. To eliminate the need for manholes
C. To allow wastewater to flow by gravity
D. To prevent all solids from entering the sewer
Rationale: Gravity sewers are installed at designed slopes so
wastewater flows from higher elevations toward lower elevations
without continuous pumping. The specified grade must account for
pipe size, flow conditions, project requirements, and applicable design
standards.
6. What is meant by “infiltration” in a sanitary sewer system?
A. Wastewater escaping through a pipe joint
B. Groundwater entering the sewer through defects or openings
C. Rainwater flowing across a paved road
D. Air entering a ventilation stack from the roof
Rationale: Infiltration occurs when groundwater enters a sewer
through cracks, defective joints, damaged manholes, or other
openings. Excessive infiltration can increase treatment costs, overload
collection systems, and contribute to sanitary sewer overflows.
7. What is “exfiltration” in sewer construction?
