TEXAS WASTEWATER OPERATOR LICENSE VERSION B EXAM READY -
VERIFIED QUESTIONS AND ANSWERS - COMPREHENSIVE LATEST
VERSION 2026/2027
Question 1: What is the primary purpose of a wastewater collection
system?
A) To convey wastewater from B) To treat wastewater before
homes and businesses to the discharge
treatment facility
C) To store stormwater runoff D) To distribute drinking water
✓ Correct Answer: A Collection systems transport wastewater via
gravity mains, lift stations, and force mains to the treatment plant.
Question 2: Which type of sewer system carries both sanitary
wastewater and stormwater in the same pipe?
A) Sanitary sewer B) Combined sewer
C) Storm sewer D) Interceptor sewer
✓ Correct Answer: B A combined sewer carries both sewage and
stormwater in a single pipe system.
Question 3: What is the minimum slope recommended for an 8-inch
sanitary sewer to maintain self-cleaning velocity?
A) 0.01% B) 0.05%
C) 0.40% D) 1.00%
✓ Correct Answer: C An 8-inch pipe requires approximately 0.40%
slope to achieve the 2 ft/s self-cleaning velocity.
,Question 4: The minimum self-cleaning velocity in a wastewater
collection pipe is generally considered to be:
A) 1.0 ft/s B) 2.0 ft/s
C) 3.5 ft/s D) 5.0 ft/s
✓ Correct Answer: B 2.0 ft/s is the standard minimum velocity to
prevent solids from settling in collection mains.
Question 5: Which gas is most commonly associated with hydrogen
sulfide production in wastewater collection systems?
A) H₂S B) CH₄
C) CO₂ D) NH₃
✓ Correct Answer: A Hydrogen sulfide (H₂S) is produced by anaerobic
bacteria reducing sulfates in the sewer atmosphere.
Question 6: A lift station wet well should be sized to provide a
minimum detention time of:
A) 1 minute B) 5 minutes
C) 30 minutes or less to prevent D) 2 hours
septic conditions
✓ Correct Answer: C Long detention times cause septic conditions;
wet wells are typically sized for <30 min at average flow.
Question 7: Which instrument is used to measure the flow rate in a
gravity sewer?
A) Rotameter B) Venturi meter
C) Orifice plate D) Doppler flow meter
✓ Correct Answer: D Doppler ultrasonic flow meters are widely used in
gravity sewers to measure velocity and depth.
,Question 8: Infiltration in a collection system refers to:
A) Groundwater entering the sewer B) Wastewater leaking out of the
through defective pipes or joints sewer
C) Stormwater entering through D) Pumping of sewage into force
manholes mains
✓ Correct Answer: A Infiltration is unwanted groundwater entry; inflow
is stormwater entry through direct connections.
Question 9: What is the purpose of a manhole in a sewer system?
A) To prevent odors from escaping B) To provide access for inspection,
maintenance, and cleaning
C) To reduce flow velocity D) To separate grit from wastewater
✓ Correct Answer: B Manholes provide access points for crews to
inspect, clean, and repair collection mains.
Question 10: When cleaning a sewer main with a jetter, the nozzle is
typically directed:
A) Downstream with the flow B) Vertically downward
C) Upstream against the flow D) At 45° to the pipe wall
✓ Correct Answer: C Jetter nozzles face upstream so high-pressure
water cuts debris loose and the flow carries it downstream.
Question 11: A force main in a collection system operates:
A) By gravity only B) Under pressure from a pump
C) By vacuum D) By compressed air
✓ Correct Answer: B Force mains are pressurized pipes connected to
lift station pumps to convey sewage uphill or over distances.
Question 12: The maximum recommended spacing between
manholes in a straight sewer run is generally:
, A) 100 feet B) 200 feet
C) 300 feet D) 400–500 feet
✓ Correct Answer: D Texas regulations and standard practice allow up
to 400–500 ft spacing for straight pipe segments.
Question 13: Which type of pipe is most commonly used in new
sanitary sewer construction?
A) PVC (polyvinyl chloride) B) Cast iron
C) Asbestos cement D) Vitrified clay
✓ Correct Answer: A PVC is the dominant material for new sewer
construction due to its durability, smooth interior, and cost.
Question 14: Smoke testing of a sewer system is primarily used to
locate:
A) H₂S gas pockets B) Pipe material type
C) Illegal storm/roof drain D) Pipe diameter changes
connections and leaks
✓ Correct Answer: C Smoke is blown into the sewer; smoke emerging
from yards, storm drains, or buildings indicates illicit connections.
Question 15: A CCTV inspection of a sewer main is performed to:
A) Measure flow rates B) Visually assess the interior
condition and identify defects
C) Test for H₂S concentrations D) Verify manhole ring elevations
✓ Correct Answer: B Closed-circuit TV cameras are pulled through
pipes to identify cracks, root intrusion, offsets, and blockages.
Question 16: Which condition causes most sanitary sewer
overflows (SSOs)?
A) Excessive flow velocity B) Pipe diameter too large
VERIFIED QUESTIONS AND ANSWERS - COMPREHENSIVE LATEST
VERSION 2026/2027
Question 1: What is the primary purpose of a wastewater collection
system?
A) To convey wastewater from B) To treat wastewater before
homes and businesses to the discharge
treatment facility
C) To store stormwater runoff D) To distribute drinking water
✓ Correct Answer: A Collection systems transport wastewater via
gravity mains, lift stations, and force mains to the treatment plant.
Question 2: Which type of sewer system carries both sanitary
wastewater and stormwater in the same pipe?
A) Sanitary sewer B) Combined sewer
C) Storm sewer D) Interceptor sewer
✓ Correct Answer: B A combined sewer carries both sewage and
stormwater in a single pipe system.
Question 3: What is the minimum slope recommended for an 8-inch
sanitary sewer to maintain self-cleaning velocity?
A) 0.01% B) 0.05%
C) 0.40% D) 1.00%
✓ Correct Answer: C An 8-inch pipe requires approximately 0.40%
slope to achieve the 2 ft/s self-cleaning velocity.
,Question 4: The minimum self-cleaning velocity in a wastewater
collection pipe is generally considered to be:
A) 1.0 ft/s B) 2.0 ft/s
C) 3.5 ft/s D) 5.0 ft/s
✓ Correct Answer: B 2.0 ft/s is the standard minimum velocity to
prevent solids from settling in collection mains.
Question 5: Which gas is most commonly associated with hydrogen
sulfide production in wastewater collection systems?
A) H₂S B) CH₄
C) CO₂ D) NH₃
✓ Correct Answer: A Hydrogen sulfide (H₂S) is produced by anaerobic
bacteria reducing sulfates in the sewer atmosphere.
Question 6: A lift station wet well should be sized to provide a
minimum detention time of:
A) 1 minute B) 5 minutes
C) 30 minutes or less to prevent D) 2 hours
septic conditions
✓ Correct Answer: C Long detention times cause septic conditions;
wet wells are typically sized for <30 min at average flow.
Question 7: Which instrument is used to measure the flow rate in a
gravity sewer?
A) Rotameter B) Venturi meter
C) Orifice plate D) Doppler flow meter
✓ Correct Answer: D Doppler ultrasonic flow meters are widely used in
gravity sewers to measure velocity and depth.
,Question 8: Infiltration in a collection system refers to:
A) Groundwater entering the sewer B) Wastewater leaking out of the
through defective pipes or joints sewer
C) Stormwater entering through D) Pumping of sewage into force
manholes mains
✓ Correct Answer: A Infiltration is unwanted groundwater entry; inflow
is stormwater entry through direct connections.
Question 9: What is the purpose of a manhole in a sewer system?
A) To prevent odors from escaping B) To provide access for inspection,
maintenance, and cleaning
C) To reduce flow velocity D) To separate grit from wastewater
✓ Correct Answer: B Manholes provide access points for crews to
inspect, clean, and repair collection mains.
Question 10: When cleaning a sewer main with a jetter, the nozzle is
typically directed:
A) Downstream with the flow B) Vertically downward
C) Upstream against the flow D) At 45° to the pipe wall
✓ Correct Answer: C Jetter nozzles face upstream so high-pressure
water cuts debris loose and the flow carries it downstream.
Question 11: A force main in a collection system operates:
A) By gravity only B) Under pressure from a pump
C) By vacuum D) By compressed air
✓ Correct Answer: B Force mains are pressurized pipes connected to
lift station pumps to convey sewage uphill or over distances.
Question 12: The maximum recommended spacing between
manholes in a straight sewer run is generally:
, A) 100 feet B) 200 feet
C) 300 feet D) 400–500 feet
✓ Correct Answer: D Texas regulations and standard practice allow up
to 400–500 ft spacing for straight pipe segments.
Question 13: Which type of pipe is most commonly used in new
sanitary sewer construction?
A) PVC (polyvinyl chloride) B) Cast iron
C) Asbestos cement D) Vitrified clay
✓ Correct Answer: A PVC is the dominant material for new sewer
construction due to its durability, smooth interior, and cost.
Question 14: Smoke testing of a sewer system is primarily used to
locate:
A) H₂S gas pockets B) Pipe material type
C) Illegal storm/roof drain D) Pipe diameter changes
connections and leaks
✓ Correct Answer: C Smoke is blown into the sewer; smoke emerging
from yards, storm drains, or buildings indicates illicit connections.
Question 15: A CCTV inspection of a sewer main is performed to:
A) Measure flow rates B) Visually assess the interior
condition and identify defects
C) Test for H₂S concentrations D) Verify manhole ring elevations
✓ Correct Answer: B Closed-circuit TV cameras are pulled through
pipes to identify cracks, root intrusion, offsets, and blockages.
Question 16: Which condition causes most sanitary sewer
overflows (SSOs)?
A) Excessive flow velocity B) Pipe diameter too large
