C E R T I FI C AT I ON E X A M I N AT I ON
CWEA Collections
Grade 1 Exam
100 Questions and Verified Answers Aligned with 2026-2027 CWEA Collection
N O I TA I C O S S A T N E M N O R I V N E R E TAW A I N R O F I L A C
System Maintenance Grade 1 Certification Standards and Exam Blueprint
Update | Grade A Verified Answers
4 Sections | Systems Operations, Documentation, Safety, Tools & Equipment
COLLE CTI ON SY STE M MA I NTE NA NCE CE RTI FI CATI ON
, Section 1: Systems Operations, Inspections, and Maintenance (36%)
Questions Q1 – Q36
Q1. A collection system technician is investigating repeated blockages in a residential area. The system map
shows the affected sewer main is a gravity sewer with a consistent slope of 0.5%. Which of the following is the
MOST likely cause of the recurring blockages in this gravity sewer segment?
A. The slope is too steep, causing excessive velocity that erodes pipe joints
B. The slope is too flat, resulting in insufficient velocity to transport solids effectively [CORRECT]
C. The pipe material is incompatible with the wastewater chemistry
D. The diameter of the pipe is too large for the connected laterals
Correct Answer: B
Rationale: Gravity sewers rely on proper slope to maintain self-cleansing velocities, typically between 2-3 feet per second. A slope of
0.5% may be too flat for the pipe diameter, reducing flow velocity below the minimum needed to transport solids. This causes solids to
settle and accumulate, leading to repeated blockages. Excessive steepness (A) causes other problems like erosion but not recurring
blockages from sediment. Pipe material incompatibility (C) typically causes corrosion, not repeated blockages. An oversized pipe (D)
would further reduce velocity but the root cause is the flat slope.
Q2. Which of the following BEST describes the primary function of a force main in a wastewater collection
system?
A. It conveys wastewater by gravity from higher elevations to lower elevations
B. It transports wastewater under pressure from a pump station to a discharge point [CORRECT]
C. It stores wastewater temporarily during peak flow periods
D. It allows for the diversion of flow during maintenance activities
Correct Answer: B
Rationale: A force main is a pressurized pipe that carries wastewater from a pump or lift station to a higher elevation discharge point,
such as a gravity sewer or treatment plant. Unlike gravity sewers, force mains rely on pump pressure rather than slope to move
wastewater. Gravity sewers (A) use elevation differences. Storage is provided by wet wells (C). Flow diversion (D) uses bypass piping or
valves.
Q3. A Grade 1 technician responds to a high-water alarm at a lift station. Upon arrival, the technician
observes that the pumps are not running despite the high water level in the wet well. Which of the following
should be the technician's FIRST action?
A. Bypass the control panel and manually start the pumps to lower the water level
B. Check the control panel for alarm codes and verify power supply to the station [CORRECT]
C. Call the treatment plant to notify them of a potential overflow event
D. Begin containment procedures and deploy spill booms around the station
Correct Answer: B
Rationale: The first action should be to diagnose the problem systematically by checking the control panel for alarm codes and verifying
the power supply. This helps identify whether the issue is electrical, mechanical, or control-system related. Manually bypassing controls
(A) could damage equipment or create safety hazards without understanding the failure mode. Notifying the treatment plant (C) and
deploying containment (D) may become necessary if the situation worsens, but the immediate priority is diagnosing why the pumps
failed to respond.
, Q4. Which of the following components of a manhole is PRIMARILY responsible for directing wastewater
flow from the inlet channel into the outgoing sewer without creating turbulence?
A. The manhole frame and cover
B. The bench or channel invert [CORRECT]
C. The manhole steps or ladder
D. The manhole cone or chimney section
Correct Answer: B
Rationale: The bench, also called the channel invert, is the shaped bottom of the manhole that channels wastewater smoothly from the
inlet pipe to the outlet pipe. Its design minimizes turbulence, prevents solids deposition, and maintains flow velocity. The frame and
cover (A) provide access and surface protection. Steps (C) provide worker access. The cone or chimney (D) is the upper tapered section
transitioning to street level.
Q5. A homeowner reports a backup in their basement plumbing during heavy rain events. The collection
system technician determines that the lateral serving the home is functioning properly, and the main sewer is
not surcharging. Which of the following is the MOST probable cause of the backup?
A. The lateral is undersized for the home's fixture flow rate
B. Inflow from the homeowner's downspouts and foundation drains is connected to the sanitary lateral
[CORRECT]
C. The main sewer has a partial blockage downstream of the lateral connection
D. The lift station serving the area is operating at reduced capacity
Correct Answer: B
Rationale: When a lateral backs up only during heavy rain despite being clear and the main not surcharging, the most probable cause is
clear water inflow from downspouts, foundation drains, or area drains illegally connected to the sanitary lateral. This excess clear water
overwhelms the lateral capacity during rain events. An undersized lateral (A) would cause backups during normal usage. A downstream
blockage (C) would likely affect multiple homes. A reduced-capacity lift station (D) would cause the main to surcharge.
Q6. In a wastewater collection system, an inverted siphon is used to convey flow under an obstruction such as
a river or highway. What MUST be provided at the downstream end of the inverted siphon to restore gravity
flow conditions?
A. A force main connection point
B. A vent to release trapped air and gases [CORRECT]
C. An access manhole at the upstream end only
D. A flow meter to measure the pressurized flow rate
Correct Answer: B
Rationale: Inverted siphons operate under pressure, which can trap air and gases at high points. Air vents at the downstream end are
essential to release trapped gases that could otherwise restrict flow, reduce capacity, or cause surging. A force main connection (A) is
not needed. Access manholes (C) are needed at both ends, not just upstream. Flow meters (D) are useful but not essential for restoring
gravity flow.
Q7. A technician has just completed clearing a blockage using a power rodder. The machine is still powered
on, and the rod is retracting through the guide hose. Which of the following safety procedures is MOST
critical before handling the cutting head at the end of the rod?
A. Wear chemical-resistant gloves to protect against wastewater residue on the rod
B. Ensure all torque is out of the machine before handling the cutting head [CORRECT]
C. Disconnect the power supply to the rodder before the rod fully retracts
D. Apply a lubricant to the cutting head to prevent rust after cleaning
CWEA Collections
Grade 1 Exam
100 Questions and Verified Answers Aligned with 2026-2027 CWEA Collection
N O I TA I C O S S A T N E M N O R I V N E R E TAW A I N R O F I L A C
System Maintenance Grade 1 Certification Standards and Exam Blueprint
Update | Grade A Verified Answers
4 Sections | Systems Operations, Documentation, Safety, Tools & Equipment
COLLE CTI ON SY STE M MA I NTE NA NCE CE RTI FI CATI ON
, Section 1: Systems Operations, Inspections, and Maintenance (36%)
Questions Q1 – Q36
Q1. A collection system technician is investigating repeated blockages in a residential area. The system map
shows the affected sewer main is a gravity sewer with a consistent slope of 0.5%. Which of the following is the
MOST likely cause of the recurring blockages in this gravity sewer segment?
A. The slope is too steep, causing excessive velocity that erodes pipe joints
B. The slope is too flat, resulting in insufficient velocity to transport solids effectively [CORRECT]
C. The pipe material is incompatible with the wastewater chemistry
D. The diameter of the pipe is too large for the connected laterals
Correct Answer: B
Rationale: Gravity sewers rely on proper slope to maintain self-cleansing velocities, typically between 2-3 feet per second. A slope of
0.5% may be too flat for the pipe diameter, reducing flow velocity below the minimum needed to transport solids. This causes solids to
settle and accumulate, leading to repeated blockages. Excessive steepness (A) causes other problems like erosion but not recurring
blockages from sediment. Pipe material incompatibility (C) typically causes corrosion, not repeated blockages. An oversized pipe (D)
would further reduce velocity but the root cause is the flat slope.
Q2. Which of the following BEST describes the primary function of a force main in a wastewater collection
system?
A. It conveys wastewater by gravity from higher elevations to lower elevations
B. It transports wastewater under pressure from a pump station to a discharge point [CORRECT]
C. It stores wastewater temporarily during peak flow periods
D. It allows for the diversion of flow during maintenance activities
Correct Answer: B
Rationale: A force main is a pressurized pipe that carries wastewater from a pump or lift station to a higher elevation discharge point,
such as a gravity sewer or treatment plant. Unlike gravity sewers, force mains rely on pump pressure rather than slope to move
wastewater. Gravity sewers (A) use elevation differences. Storage is provided by wet wells (C). Flow diversion (D) uses bypass piping or
valves.
Q3. A Grade 1 technician responds to a high-water alarm at a lift station. Upon arrival, the technician
observes that the pumps are not running despite the high water level in the wet well. Which of the following
should be the technician's FIRST action?
A. Bypass the control panel and manually start the pumps to lower the water level
B. Check the control panel for alarm codes and verify power supply to the station [CORRECT]
C. Call the treatment plant to notify them of a potential overflow event
D. Begin containment procedures and deploy spill booms around the station
Correct Answer: B
Rationale: The first action should be to diagnose the problem systematically by checking the control panel for alarm codes and verifying
the power supply. This helps identify whether the issue is electrical, mechanical, or control-system related. Manually bypassing controls
(A) could damage equipment or create safety hazards without understanding the failure mode. Notifying the treatment plant (C) and
deploying containment (D) may become necessary if the situation worsens, but the immediate priority is diagnosing why the pumps
failed to respond.
, Q4. Which of the following components of a manhole is PRIMARILY responsible for directing wastewater
flow from the inlet channel into the outgoing sewer without creating turbulence?
A. The manhole frame and cover
B. The bench or channel invert [CORRECT]
C. The manhole steps or ladder
D. The manhole cone or chimney section
Correct Answer: B
Rationale: The bench, also called the channel invert, is the shaped bottom of the manhole that channels wastewater smoothly from the
inlet pipe to the outlet pipe. Its design minimizes turbulence, prevents solids deposition, and maintains flow velocity. The frame and
cover (A) provide access and surface protection. Steps (C) provide worker access. The cone or chimney (D) is the upper tapered section
transitioning to street level.
Q5. A homeowner reports a backup in their basement plumbing during heavy rain events. The collection
system technician determines that the lateral serving the home is functioning properly, and the main sewer is
not surcharging. Which of the following is the MOST probable cause of the backup?
A. The lateral is undersized for the home's fixture flow rate
B. Inflow from the homeowner's downspouts and foundation drains is connected to the sanitary lateral
[CORRECT]
C. The main sewer has a partial blockage downstream of the lateral connection
D. The lift station serving the area is operating at reduced capacity
Correct Answer: B
Rationale: When a lateral backs up only during heavy rain despite being clear and the main not surcharging, the most probable cause is
clear water inflow from downspouts, foundation drains, or area drains illegally connected to the sanitary lateral. This excess clear water
overwhelms the lateral capacity during rain events. An undersized lateral (A) would cause backups during normal usage. A downstream
blockage (C) would likely affect multiple homes. A reduced-capacity lift station (D) would cause the main to surcharge.
Q6. In a wastewater collection system, an inverted siphon is used to convey flow under an obstruction such as
a river or highway. What MUST be provided at the downstream end of the inverted siphon to restore gravity
flow conditions?
A. A force main connection point
B. A vent to release trapped air and gases [CORRECT]
C. An access manhole at the upstream end only
D. A flow meter to measure the pressurized flow rate
Correct Answer: B
Rationale: Inverted siphons operate under pressure, which can trap air and gases at high points. Air vents at the downstream end are
essential to release trapped gases that could otherwise restrict flow, reduce capacity, or cause surging. A force main connection (A) is
not needed. Access manholes (C) are needed at both ends, not just upstream. Flow meters (D) are useful but not essential for restoring
gravity flow.
Q7. A technician has just completed clearing a blockage using a power rodder. The machine is still powered
on, and the rod is retracting through the guide hose. Which of the following safety procedures is MOST
critical before handling the cutting head at the end of the rod?
A. Wear chemical-resistant gloves to protect against wastewater residue on the rod
B. Ensure all torque is out of the machine before handling the cutting head [CORRECT]
C. Disconnect the power supply to the rodder before the rod fully retracts
D. Apply a lubricant to the cutting head to prevent rust after cleaning
