Florida Wastewater Collection System
Operator Class 2 Certification Examination
Practice Questions & [Verified Answers],
Plus Explained Rationales|2026 Latest
Update| Instant Download PDF
1. A collection system operator observes that a gravity sewer is
flowing at a depth substantially below the crown of the pipe during
normal dry-weather conditions. What is the most likely hydraulic
condition?
A. The pipe is operating under surcharge
B. The pipe is flowing partially full under open-channel conditions
C. The pipe is operating under pressure
D. The pipe is completely blocked
Answer: B. The pipe is flowing partially full under open-channel
conditions
Rationale: Gravity sewers normally operate as open channels when
they are not surcharged. A partially full sewer has a free water surface
exposed to the atmosphere, while surcharge or pressure conditions
occur when the pipe becomes full and hydraulic grade rises above the
crown.
2. Which condition is most likely to cause excessive infiltration into a
sanitary sewer collection system?
1|Page
,A. A properly sealed manhole cover
B. A groundwater-saturated area surrounding a cracked sewer pipe
C. A newly installed watertight service connection
D. A properly functioning force-main air-release valve
Answer: B. A groundwater-saturated area surrounding a cracked
sewer pipe
Rationale: Infiltration is groundwater entering a sewer through
defects such as cracks, defective joints, deteriorated manholes, or
damaged service connections. The driving force is generally
groundwater pressure relative to pressure inside the sewer.
3. What is the primary difference between infiltration and inflow?
A. Infiltration is intentional water use; inflow is groundwater
B. Infiltration enters through structural defects; inflow enters through
direct connections or openings
C. Infiltration occurs only in force mains; inflow occurs only in gravity
sewers
D. There is no practical difference
Answer: B. Infiltration enters through structural defects; inflow enters
through direct connections or openings
Rationale: Infiltration generally consists of groundwater entering
through cracks, joints, manholes, and other defects. Inflow is typically
stormwater or other surface water entering through direct
connections such as roof drains, yard drains, storm drains, or
improperly connected cleanouts.
2|Page
,4. A sewer has a persistent grease accumulation near a restaurant
area. Which maintenance approach is generally most appropriate?
A. Ignore the accumulation until a blockage occurs
B. Establish a preventive cleaning program based on observed
accumulation
C. Permanently plug the sewer
D. Increase the sewer slope
Answer: B. Establish a preventive cleaning program based on
observed accumulation
Rationale: Grease-related restrictions are best managed through
documented preventive maintenance. Cleaning frequency should be
based on inspection findings, historical blockage frequency, flow
characteristics, and the source of the grease.
5. What is the primary purpose of a sewer manhole?
A. To increase wastewater temperature
B. To provide access for inspection, maintenance, cleaning, and changes
in sewer alignment or elevation
C. To disinfect wastewater
D. To eliminate infiltration automatically
Answer: B. To provide access for inspection, maintenance, cleaning,
and changes in sewer alignment or elevation
Rationale: Manholes provide operational access to the collection
system. They commonly occur at changes in alignment, grade, pipe
size, junctions, and other locations where inspection and maintenance
access is needed.
3|Page
, 6. A collection-system operator finds a manhole with significant
groundwater entering through a deteriorated wall joint. What type of
problem is this?
A. Inflow
B. Infiltration
C. Hydraulic shock
D. Backflow from a force main
Answer: B. Infiltration
Rationale: Groundwater entering through a structural defect in a
manhole is infiltration. The defect provides a pathway for
groundwater to enter the sanitary sewer system.
7. Which instrument is commonly used to determine the depth of
wastewater in a wet well?
A. pH meter only
B. Level sensor or ultrasonic level transmitter
C. Chlorine comparator
D. Turbidity tube
Answer: B. Level sensor or ultrasonic level transmitter
Rationale: Pump stations commonly use level sensors, floats, pressure
transducers, or ultrasonic instruments to monitor wet-well level and
control pump operation.
8. A pump station's pumps are cycling on and off much more
frequently than normal. Which condition should be investigated first?
4|Page
Operator Class 2 Certification Examination
Practice Questions & [Verified Answers],
Plus Explained Rationales|2026 Latest
Update| Instant Download PDF
1. A collection system operator observes that a gravity sewer is
flowing at a depth substantially below the crown of the pipe during
normal dry-weather conditions. What is the most likely hydraulic
condition?
A. The pipe is operating under surcharge
B. The pipe is flowing partially full under open-channel conditions
C. The pipe is operating under pressure
D. The pipe is completely blocked
Answer: B. The pipe is flowing partially full under open-channel
conditions
Rationale: Gravity sewers normally operate as open channels when
they are not surcharged. A partially full sewer has a free water surface
exposed to the atmosphere, while surcharge or pressure conditions
occur when the pipe becomes full and hydraulic grade rises above the
crown.
2. Which condition is most likely to cause excessive infiltration into a
sanitary sewer collection system?
1|Page
,A. A properly sealed manhole cover
B. A groundwater-saturated area surrounding a cracked sewer pipe
C. A newly installed watertight service connection
D. A properly functioning force-main air-release valve
Answer: B. A groundwater-saturated area surrounding a cracked
sewer pipe
Rationale: Infiltration is groundwater entering a sewer through
defects such as cracks, defective joints, deteriorated manholes, or
damaged service connections. The driving force is generally
groundwater pressure relative to pressure inside the sewer.
3. What is the primary difference between infiltration and inflow?
A. Infiltration is intentional water use; inflow is groundwater
B. Infiltration enters through structural defects; inflow enters through
direct connections or openings
C. Infiltration occurs only in force mains; inflow occurs only in gravity
sewers
D. There is no practical difference
Answer: B. Infiltration enters through structural defects; inflow enters
through direct connections or openings
Rationale: Infiltration generally consists of groundwater entering
through cracks, joints, manholes, and other defects. Inflow is typically
stormwater or other surface water entering through direct
connections such as roof drains, yard drains, storm drains, or
improperly connected cleanouts.
2|Page
,4. A sewer has a persistent grease accumulation near a restaurant
area. Which maintenance approach is generally most appropriate?
A. Ignore the accumulation until a blockage occurs
B. Establish a preventive cleaning program based on observed
accumulation
C. Permanently plug the sewer
D. Increase the sewer slope
Answer: B. Establish a preventive cleaning program based on
observed accumulation
Rationale: Grease-related restrictions are best managed through
documented preventive maintenance. Cleaning frequency should be
based on inspection findings, historical blockage frequency, flow
characteristics, and the source of the grease.
5. What is the primary purpose of a sewer manhole?
A. To increase wastewater temperature
B. To provide access for inspection, maintenance, cleaning, and changes
in sewer alignment or elevation
C. To disinfect wastewater
D. To eliminate infiltration automatically
Answer: B. To provide access for inspection, maintenance, cleaning,
and changes in sewer alignment or elevation
Rationale: Manholes provide operational access to the collection
system. They commonly occur at changes in alignment, grade, pipe
size, junctions, and other locations where inspection and maintenance
access is needed.
3|Page
, 6. A collection-system operator finds a manhole with significant
groundwater entering through a deteriorated wall joint. What type of
problem is this?
A. Inflow
B. Infiltration
C. Hydraulic shock
D. Backflow from a force main
Answer: B. Infiltration
Rationale: Groundwater entering through a structural defect in a
manhole is infiltration. The defect provides a pathway for
groundwater to enter the sanitary sewer system.
7. Which instrument is commonly used to determine the depth of
wastewater in a wet well?
A. pH meter only
B. Level sensor or ultrasonic level transmitter
C. Chlorine comparator
D. Turbidity tube
Answer: B. Level sensor or ultrasonic level transmitter
Rationale: Pump stations commonly use level sensors, floats, pressure
transducers, or ultrasonic instruments to monitor wet-well level and
control pump operation.
8. A pump station's pumps are cycling on and off much more
frequently than normal. Which condition should be investigated first?
4|Page
