1
CWEA Collection Systems Maintenance Grades
2 Actual Exam 2026/2027 | Complete Exam-Style
Questions | 100% Verified – Detailed Rationales –
Pass Guaranteed – A+ Graded
TABLE OF CONTENTS
Section 1 | Collection System Operations and Maintenance | Q1 – Q20
Section 2 | Safety Procedures and OSHA Compliance | Q21 – Q40
Section 3 | Equipment, Tools, and Vehicle Operation | Q41 – Q60
Section 4 | Pipe Inspection, Testing, and Rehabilitation | Q61 – Q80
Section 5 | Regulatory Compliance, Recordkeeping, and Public Relations | Q81 – Q100
SECTION 1: COLLECTION SYSTEM OPERATIONS AND MAINTENANCE
Question 1 of 100
A gravity sewer line in a residential neighborhood has experienced recurring backups during peak
morning hours. Flow monitoring indicates velocities drop below 2 feet per second during low-flow
periods, allowing solids to settle and grease to accumulate on the pipe crown. The maintenance
supervisor is evaluating cleaning frequencies and methods to restore proper hydraulic capacity.
A. Increase the cleaning cycle to quarterly and use a high-velocity jet nozzle with rear-facing jets
to scour the pipe invert
B. Schedule annual CCTV inspection only and defer cleaning until a blockage occurs to conserve
operational budget
C. Implement a monthly high-velocity jetting program with a nozzle designed for grease removal
and verify post-cleaning flow velocities ✓ CORRECT
D. Apply chemical degreasing agents through downstream manholes without mechanical cleaning
and reduce inspection frequency
Correct Answer: C
Rationale: Monthly high-velocity jetting with a grease-cutting nozzle restores self-cleansing
velocities and prevents accumulation, which aligns with CWEA best practices for gravity sewer
maintenance. Option A is incorrect because quarterly cleaning is insufficient for a line with
documented low-flow deposition and recurring backups. Field crews should always verify flow
restoration with post-cleaning flow data when available.
Question 2 of 100
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During a routine manhole inspection in a 20-year-old clay pipe system, an operator observes
significant root intrusion at a joint located 8 feet upstream from a manhole. The roots have formed
a dense mat that is partially obstructing flow but has not yet caused a complete blockage. The crew
has a root cutter, a jet truck, and chemical root foam available.
A. Apply chemical root foam immediately without mechanical cutting, as the foam will penetrate
and kill the roots over time
B. Cut the roots mechanically with a root saw attached to a jet hose, then apply approved root-
inhibiting foam to retard regrowth ✓ CORRECT
C. Excavate and replace the joint immediately, as any root intrusion indicates structural failure
requiring full repair
D. Monitor the intrusion monthly and document growth patterns without intervention until flow is
fully obstructed
Correct Answer: B
Rationale: Mechanical cutting removes the existing root mass to restore flow capacity, and the
follow-up application of approved foam inhibits regrowth without immediate excavation, which is
the standard CWEA approach for moderate root intrusion. Option A is incorrect because applying
foam without mechanical removal leaves the root mat in place, continuing to obstruct flow and
potentially causing a backup. Crews should always clear the obstruction first before applying
chemical treatments.
Question 3 of 100
A collection system operator is responding to a wet weather event where infiltration is causing
excessive flows at a lift station. The influent flow rate has risen from 800 gpm to 2,400 gpm within
two hours, and the wet well is approaching the high-level alarm setpoint. The lead pump is running
continuously, and the lag pump has cycled on twice in the past 30 minutes.
A. Activate all available pumps including the standby unit and notify downstream treatment plant
of increased flows ✓ CORRECT
B. Close the influent gate valve to reduce inflow and prevent the wet well from overflowing
C. Increase the pump lead/lag differential by 12 inches to reduce cycle frequency and extend pump
motor life
D. Dispatch a crew to begin smoke testing in the service area to identify infiltration sources during
the storm
Correct Answer: A
Rationale: Activating all available pumping capacity and communicating with the treatment plant
is the immediate operational response to prevent a sanitary sewer overflow during extreme wet
weather inflow, consistent with CWEA emergency operations protocols. Option B is incorrect
because closing an influent gate valve would cause upstream surcharging and basement backups,
,3
creating a public health emergency. Operators must always prioritize preventing SSOs over
equipment cycling concerns during storm events.
Question 4 of 100
An operator is evaluating odor complaints from residents near a 24-inch trunk sewer that conveys
flows from a commercial district with multiple restaurants. H2S readings at the downstream
manhole have reached 35 ppm, and corrosion is visible on the concrete bench and ladder. The
system manager needs a long-term control strategy.
A. Install passive carbon filters on all manhole covers in the neighborhood to absorb vented gases
B. Add calcium nitrate to the upstream sewer to provide an alternate electron acceptor and suppress
sulfate-reducing bacteria activity ✓ CORRECT
C. Seal all manholes with airtight gaskets and redirect vented gases into residential storm drains
D. Schedule weekly jetting of the entire trunk line to remove all biofilm and organic deposits
Correct Answer: B
Rationale: Calcium nitrate provides an alternative electron acceptor that suppresses the biological
sulfate reduction responsible for H2S generation, making it a standard and effective long-term
odor and corrosion control strategy in high-grease commercial sewers. Option A is incorrect
because passive carbon filters only treat gases already vented from the system and do not address
the root cause of generation or ongoing corrosion. A comprehensive odor control program must
target the biological process creating the H2S.
Question 5 of 100
A maintenance crew is performing post-storm assessment on a 15-inch reinforced concrete pipe
that crosses beneath a seasonal creek. The operator notices that the streambank has eroded,
exposing the top quadrant of the pipe and revealing a longitudinal crack with visible soil
infiltration. Flow in the pipe remains normal, and no sinkhole has formed.
A. Place sandbags around the exposed section and schedule inspection in six months after the rainy
season ends
B. Install a steel sleeve around the pipe and backfill with native soil to restore streambank support
C. Immediately report the structural defect, isolate the line if possible, and initiate emergency
repair or bypass pumping ✓ CORRECT
D. Apply hydraulic cement to the exterior crack and monitor for changes during the next routine
CCTV cycle
Correct Answer: C
Rationale: An exposed trunk sewer with a longitudinal crack and active soil infiltration represents
an imminent structural failure risk that requires immediate reporting and emergency stabilization
to prevent collapse or contamination of the waterway. Option A is incorrect because delaying
, 4
action through a full rainy season allows continued erosion and infiltration, which could result in
catastrophic pipe collapse during the next storm event. CWEA standards require prompt response
to stream-crossing exposure.
Question 6 of 100
An operator is troubleshooting a gravity sewer line that serves a hillside residential area with
homes at elevations ranging from 120 feet to 280 feet above the main trunk. Several lower-
elevation homes report slow drains, while upper-elevation homes experience no issues. The line
profile shows a flat section between MH-12 and MH-13 with minimal slope.
A. Install a lift station at the upper end of the flat section to boost flows and increase velocity
B. Regrade the flat section to achieve minimum 0.5% slope or install a drop manhole to restore
adequate carrying velocity ✓ CORRECT
C. Increase the pipe diameter from 8 inches to 12 inches through the flat section to reduce friction
losses
D. Require upper-elevation residents to reduce water usage during peak hours to prevent system
overload
Correct Answer: B
Rationale: Regrading to achieve proper slope or installing a drop manhole restores self-cleansing
velocity in the flat section, which is the fundamental hydraulic correction for a gravity line with
inadequate slope per CWEA design and maintenance standards. Option A is incorrect because
installing a lift station in an existing gravity system is unnecessarily complex and costly when a
slope correction can maintain gravity flow. Operators should always evaluate hydraulic grade line
and slope before considering pumped solutions.
Question 7 of 100
During a nighttime emergency response to a sewer backup in a commercial district, the operator
observes that wastewater is discharging from a cleanout at a restaurant and flowing across the
parking lot toward a storm drain. The backup is caused by a complete grease blockage 60 feet
upstream. The crew has a jet truck on scene but no vacuum capability.
A. Begin jetting upstream immediately to break the grease blockage and allow flow to resume
normally ✓ CORRECT
B. Place absorbent booms around the storm drain inlet and wait for daylight to begin cleaning
operations
C. Divert the parking lot flow into a portable tank and transport it to the treatment plant before
addressing the blockage
D. Notify the restaurant to close until a vacuum truck can be dispatched the following morning
Correct Answer: A
CWEA Collection Systems Maintenance Grades
2 Actual Exam 2026/2027 | Complete Exam-Style
Questions | 100% Verified – Detailed Rationales –
Pass Guaranteed – A+ Graded
TABLE OF CONTENTS
Section 1 | Collection System Operations and Maintenance | Q1 – Q20
Section 2 | Safety Procedures and OSHA Compliance | Q21 – Q40
Section 3 | Equipment, Tools, and Vehicle Operation | Q41 – Q60
Section 4 | Pipe Inspection, Testing, and Rehabilitation | Q61 – Q80
Section 5 | Regulatory Compliance, Recordkeeping, and Public Relations | Q81 – Q100
SECTION 1: COLLECTION SYSTEM OPERATIONS AND MAINTENANCE
Question 1 of 100
A gravity sewer line in a residential neighborhood has experienced recurring backups during peak
morning hours. Flow monitoring indicates velocities drop below 2 feet per second during low-flow
periods, allowing solids to settle and grease to accumulate on the pipe crown. The maintenance
supervisor is evaluating cleaning frequencies and methods to restore proper hydraulic capacity.
A. Increase the cleaning cycle to quarterly and use a high-velocity jet nozzle with rear-facing jets
to scour the pipe invert
B. Schedule annual CCTV inspection only and defer cleaning until a blockage occurs to conserve
operational budget
C. Implement a monthly high-velocity jetting program with a nozzle designed for grease removal
and verify post-cleaning flow velocities ✓ CORRECT
D. Apply chemical degreasing agents through downstream manholes without mechanical cleaning
and reduce inspection frequency
Correct Answer: C
Rationale: Monthly high-velocity jetting with a grease-cutting nozzle restores self-cleansing
velocities and prevents accumulation, which aligns with CWEA best practices for gravity sewer
maintenance. Option A is incorrect because quarterly cleaning is insufficient for a line with
documented low-flow deposition and recurring backups. Field crews should always verify flow
restoration with post-cleaning flow data when available.
Question 2 of 100
,2
During a routine manhole inspection in a 20-year-old clay pipe system, an operator observes
significant root intrusion at a joint located 8 feet upstream from a manhole. The roots have formed
a dense mat that is partially obstructing flow but has not yet caused a complete blockage. The crew
has a root cutter, a jet truck, and chemical root foam available.
A. Apply chemical root foam immediately without mechanical cutting, as the foam will penetrate
and kill the roots over time
B. Cut the roots mechanically with a root saw attached to a jet hose, then apply approved root-
inhibiting foam to retard regrowth ✓ CORRECT
C. Excavate and replace the joint immediately, as any root intrusion indicates structural failure
requiring full repair
D. Monitor the intrusion monthly and document growth patterns without intervention until flow is
fully obstructed
Correct Answer: B
Rationale: Mechanical cutting removes the existing root mass to restore flow capacity, and the
follow-up application of approved foam inhibits regrowth without immediate excavation, which is
the standard CWEA approach for moderate root intrusion. Option A is incorrect because applying
foam without mechanical removal leaves the root mat in place, continuing to obstruct flow and
potentially causing a backup. Crews should always clear the obstruction first before applying
chemical treatments.
Question 3 of 100
A collection system operator is responding to a wet weather event where infiltration is causing
excessive flows at a lift station. The influent flow rate has risen from 800 gpm to 2,400 gpm within
two hours, and the wet well is approaching the high-level alarm setpoint. The lead pump is running
continuously, and the lag pump has cycled on twice in the past 30 minutes.
A. Activate all available pumps including the standby unit and notify downstream treatment plant
of increased flows ✓ CORRECT
B. Close the influent gate valve to reduce inflow and prevent the wet well from overflowing
C. Increase the pump lead/lag differential by 12 inches to reduce cycle frequency and extend pump
motor life
D. Dispatch a crew to begin smoke testing in the service area to identify infiltration sources during
the storm
Correct Answer: A
Rationale: Activating all available pumping capacity and communicating with the treatment plant
is the immediate operational response to prevent a sanitary sewer overflow during extreme wet
weather inflow, consistent with CWEA emergency operations protocols. Option B is incorrect
because closing an influent gate valve would cause upstream surcharging and basement backups,
,3
creating a public health emergency. Operators must always prioritize preventing SSOs over
equipment cycling concerns during storm events.
Question 4 of 100
An operator is evaluating odor complaints from residents near a 24-inch trunk sewer that conveys
flows from a commercial district with multiple restaurants. H2S readings at the downstream
manhole have reached 35 ppm, and corrosion is visible on the concrete bench and ladder. The
system manager needs a long-term control strategy.
A. Install passive carbon filters on all manhole covers in the neighborhood to absorb vented gases
B. Add calcium nitrate to the upstream sewer to provide an alternate electron acceptor and suppress
sulfate-reducing bacteria activity ✓ CORRECT
C. Seal all manholes with airtight gaskets and redirect vented gases into residential storm drains
D. Schedule weekly jetting of the entire trunk line to remove all biofilm and organic deposits
Correct Answer: B
Rationale: Calcium nitrate provides an alternative electron acceptor that suppresses the biological
sulfate reduction responsible for H2S generation, making it a standard and effective long-term
odor and corrosion control strategy in high-grease commercial sewers. Option A is incorrect
because passive carbon filters only treat gases already vented from the system and do not address
the root cause of generation or ongoing corrosion. A comprehensive odor control program must
target the biological process creating the H2S.
Question 5 of 100
A maintenance crew is performing post-storm assessment on a 15-inch reinforced concrete pipe
that crosses beneath a seasonal creek. The operator notices that the streambank has eroded,
exposing the top quadrant of the pipe and revealing a longitudinal crack with visible soil
infiltration. Flow in the pipe remains normal, and no sinkhole has formed.
A. Place sandbags around the exposed section and schedule inspection in six months after the rainy
season ends
B. Install a steel sleeve around the pipe and backfill with native soil to restore streambank support
C. Immediately report the structural defect, isolate the line if possible, and initiate emergency
repair or bypass pumping ✓ CORRECT
D. Apply hydraulic cement to the exterior crack and monitor for changes during the next routine
CCTV cycle
Correct Answer: C
Rationale: An exposed trunk sewer with a longitudinal crack and active soil infiltration represents
an imminent structural failure risk that requires immediate reporting and emergency stabilization
to prevent collapse or contamination of the waterway. Option A is incorrect because delaying
, 4
action through a full rainy season allows continued erosion and infiltration, which could result in
catastrophic pipe collapse during the next storm event. CWEA standards require prompt response
to stream-crossing exposure.
Question 6 of 100
An operator is troubleshooting a gravity sewer line that serves a hillside residential area with
homes at elevations ranging from 120 feet to 280 feet above the main trunk. Several lower-
elevation homes report slow drains, while upper-elevation homes experience no issues. The line
profile shows a flat section between MH-12 and MH-13 with minimal slope.
A. Install a lift station at the upper end of the flat section to boost flows and increase velocity
B. Regrade the flat section to achieve minimum 0.5% slope or install a drop manhole to restore
adequate carrying velocity ✓ CORRECT
C. Increase the pipe diameter from 8 inches to 12 inches through the flat section to reduce friction
losses
D. Require upper-elevation residents to reduce water usage during peak hours to prevent system
overload
Correct Answer: B
Rationale: Regrading to achieve proper slope or installing a drop manhole restores self-cleansing
velocity in the flat section, which is the fundamental hydraulic correction for a gravity line with
inadequate slope per CWEA design and maintenance standards. Option A is incorrect because
installing a lift station in an existing gravity system is unnecessarily complex and costly when a
slope correction can maintain gravity flow. Operators should always evaluate hydraulic grade line
and slope before considering pumped solutions.
Question 7 of 100
During a nighttime emergency response to a sewer backup in a commercial district, the operator
observes that wastewater is discharging from a cleanout at a restaurant and flowing across the
parking lot toward a storm drain. The backup is caused by a complete grease blockage 60 feet
upstream. The crew has a jet truck on scene but no vacuum capability.
A. Begin jetting upstream immediately to break the grease blockage and allow flow to resume
normally ✓ CORRECT
B. Place absorbent booms around the storm drain inlet and wait for daylight to begin cleaning
operations
C. Divert the parking lot flow into a portable tank and transport it to the treatment plant before
addressing the blockage
D. Notify the restaurant to close until a vacuum truck can be dispatched the following morning
Correct Answer: A
