OPERATION AND MAINTENANCE OF WASTEWATER COLLECTION
SYSTEMS VOLUME 1 EXAM TEST QUESTIONS AND CORRECT
ANSWERS (VERIFIED ANSWERS) PLUS RATIONALES 2025/2026 Q&A
Why might timber or sheet piling used for trench shoring be left in place? - CORRECT
ANSWERS-1. If its future use is inappropriate.
2. If its removal will damage the sewer pipe or adjacent facilities.
3. To enhance the landscaping.
4. To keep property owners happy.
Why must air pressure inside the pipe during testing be great enough to overcome the water pressure
outside the pipe? - CORRECT ANSWERS-1. So air can leak out if there are cracks and holes in
the pipe.
2. So air pressure gases will be working against enough pressure for accurate readings.
3. To keep roots from entering the pipe and invalidating the air tests.
4. To prevent water from inflowing and infiltrating the pipe.
Why should all gages valves used for air testing be located outside the manhole? - CORRECT
ANSWERS-1. For ease in reading gages and adjusting valves.
2. To avoid injury to anyone reading gages and adjusting valves.
3. To facilitate accurate reading of gages and adjusting valves.
4. To prevent water damage to gages and valves.
Why should photographs be taken of the work areas on private property before starting to work? -
CORRECT ANSWERS-1. In case legal claims develop regarding cracked sidewalks and
foundations or damaged lawns and fences.
2. To gain experience using a camera to photograph pre-construction site.
3. To perform public relations activities for homeowners.
4. To provide homeowners with a nice photograph of their landscape.
When should surface restoration be started for a newly constructed sewer line? - CORRECT
ANSWERS-1. After inspection and testing have been completed.
,2. As soon as possible after excavation is finished.
3. Before testing of the system.
4. When the inspector certifies that the system is ready.
What is the main reason for using low-pressure air testing for testing sewers? - CORRECT
ANSWERS-1. Air wastage and air pollution are greater problems than water wastage.
2. More money is required for air testing than water testing.
3. More time is required to use air tests than water tests.
4. Pressurized air exerts the same pressure in all directions on the pipe.
The Operator. What is another term for wastewater collection system? - CORRECT ANSWERS-
1. Sewerage system.
2. Distribution system.
3. Pipes, pumps, and plants.
4. Sewers.
What is meant by operation and maintenance of wastewater collection system? - CORRECT
ANSWERS-1. Keeping the facilities in good operating condition.
2. Bypassing raw wastewater from the collection system.
3. Keeping the trucks operating.
4. Working with other utility agencies.
What can happen when flows in excess of the sewer capacity occur? - CORRECT ANSWERS-1.
Toilets will not flush.
2. Wastewater flows out the manhole.
3. Excess capacity is no longer available.
4. Pipes need to be expanded.
What is the result of effective operation and maintenance of a collection system? - CORRECT
ANSWERS-1. Fewer job opportunities for qualified collection system operators.
, 2. Inadequate use of available electric.
3. Overloading of the telephone system.
4. Protection of the community's capital investment in the collection system.
What does it take to become a collection system operator? - CORRECT ANSWERS-1. Desire.
2. Good luck.
3. Money.
4. Friends.
How should operators do underground sewer work? - CORRECT ANSWERS-1. Safely.
2. Economically.
3. Quickly.
4. Perfectly.
O&M. What is a major cause of corrosion in wastewater collection systems? - CORRECT
ANSWERS-1. Hydrogen sulfide gas.
2. Earth movement.
3. Pipe materials.
4. Vibration from traffic.
What is the principal cause of pipes damage that allows infiltration and exfiltration? - CORRECT
ANSWERS-1. Construction activities by other utilities.
2. Root growth.
3. Vibration from traffic.
4. Rigid pipe joints.
Why should infiltration/inflow (I/I) into collection systems be reduced? - CORRECT ANSWERS-
1. Allows collection system to handle greater quantities of wastewater.
2. Reduces potential for beach closures.
3. Dilutes strength of wastewater flowing in sewer.
SYSTEMS VOLUME 1 EXAM TEST QUESTIONS AND CORRECT
ANSWERS (VERIFIED ANSWERS) PLUS RATIONALES 2025/2026 Q&A
Why might timber or sheet piling used for trench shoring be left in place? - CORRECT
ANSWERS-1. If its future use is inappropriate.
2. If its removal will damage the sewer pipe or adjacent facilities.
3. To enhance the landscaping.
4. To keep property owners happy.
Why must air pressure inside the pipe during testing be great enough to overcome the water pressure
outside the pipe? - CORRECT ANSWERS-1. So air can leak out if there are cracks and holes in
the pipe.
2. So air pressure gases will be working against enough pressure for accurate readings.
3. To keep roots from entering the pipe and invalidating the air tests.
4. To prevent water from inflowing and infiltrating the pipe.
Why should all gages valves used for air testing be located outside the manhole? - CORRECT
ANSWERS-1. For ease in reading gages and adjusting valves.
2. To avoid injury to anyone reading gages and adjusting valves.
3. To facilitate accurate reading of gages and adjusting valves.
4. To prevent water damage to gages and valves.
Why should photographs be taken of the work areas on private property before starting to work? -
CORRECT ANSWERS-1. In case legal claims develop regarding cracked sidewalks and
foundations or damaged lawns and fences.
2. To gain experience using a camera to photograph pre-construction site.
3. To perform public relations activities for homeowners.
4. To provide homeowners with a nice photograph of their landscape.
When should surface restoration be started for a newly constructed sewer line? - CORRECT
ANSWERS-1. After inspection and testing have been completed.
,2. As soon as possible after excavation is finished.
3. Before testing of the system.
4. When the inspector certifies that the system is ready.
What is the main reason for using low-pressure air testing for testing sewers? - CORRECT
ANSWERS-1. Air wastage and air pollution are greater problems than water wastage.
2. More money is required for air testing than water testing.
3. More time is required to use air tests than water tests.
4. Pressurized air exerts the same pressure in all directions on the pipe.
The Operator. What is another term for wastewater collection system? - CORRECT ANSWERS-
1. Sewerage system.
2. Distribution system.
3. Pipes, pumps, and plants.
4. Sewers.
What is meant by operation and maintenance of wastewater collection system? - CORRECT
ANSWERS-1. Keeping the facilities in good operating condition.
2. Bypassing raw wastewater from the collection system.
3. Keeping the trucks operating.
4. Working with other utility agencies.
What can happen when flows in excess of the sewer capacity occur? - CORRECT ANSWERS-1.
Toilets will not flush.
2. Wastewater flows out the manhole.
3. Excess capacity is no longer available.
4. Pipes need to be expanded.
What is the result of effective operation and maintenance of a collection system? - CORRECT
ANSWERS-1. Fewer job opportunities for qualified collection system operators.
, 2. Inadequate use of available electric.
3. Overloading of the telephone system.
4. Protection of the community's capital investment in the collection system.
What does it take to become a collection system operator? - CORRECT ANSWERS-1. Desire.
2. Good luck.
3. Money.
4. Friends.
How should operators do underground sewer work? - CORRECT ANSWERS-1. Safely.
2. Economically.
3. Quickly.
4. Perfectly.
O&M. What is a major cause of corrosion in wastewater collection systems? - CORRECT
ANSWERS-1. Hydrogen sulfide gas.
2. Earth movement.
3. Pipe materials.
4. Vibration from traffic.
What is the principal cause of pipes damage that allows infiltration and exfiltration? - CORRECT
ANSWERS-1. Construction activities by other utilities.
2. Root growth.
3. Vibration from traffic.
4. Rigid pipe joints.
Why should infiltration/inflow (I/I) into collection systems be reduced? - CORRECT ANSWERS-
1. Allows collection system to handle greater quantities of wastewater.
2. Reduces potential for beach closures.
3. Dilutes strength of wastewater flowing in sewer.
