Maryland Dewatering Technician
Certification Exam Practice Questions
And Correct Answers (Verified
Answers) Plus Rationale 2026 Q&A|
Instant Download Pdf GRADED A+
1. The primary purpose of a wastewater collection system is
to:
A. Provide drinking water
B. Collect and transport wastewater to treatment facilities
C. Treat wastewater on-site
D. Generate electricity
Answer: B - The main function of a collection system is to move
wastewater from homes and businesses to treatment plants.
2. Sanitary sewers are designed to carry:
A. Storm water only
B. Industrial wastewater only
C. Domestic wastewater only
D. Both stormwater and domestic wastewater
Answer: C - Sanitary sewers are intended to carry domestic
wastewater, not stormwater, which is handled by storm sewers.
3. The term "inflow" refers to:
A. Groundwater entering the sewer through cracks
B. Rainwater entering the sewer through illegal connections
C. Industrial waste added to the sewer
,D. Normal wastewater from households
Answer: B - Inflow is water that enters the sewer system from
sources such as roof drains, downspouts, and yard drains.
4. The term "infiltration" refers to:
A. Unauthorized connections to the sewer
B. Groundwater entering sewer pipes through cracks or joints
C. Stormwater entering the sewer from streets
D. Excess wastewater discharged from industries
Answer: B - Infiltration is groundwater that leaks into sewer pipes
through defective joints or cracks.
5. Which material is most commonly used for modern gravity
sewer pipes?
A. Cast iron
B. Clay
C. PVC
D. Wood
Answer: C - PVC is widely used due to its durability, smooth
interior surface, and resistance to corrosion.
6. Manholes in a sewer system are primarily used for:
A. Venting gases only
B. Access for inspection and maintenance
C. Treating wastewater
D. Storing excess flow
Answer: B - Manholes provide access points for inspecting,
cleaning, and maintaining the sewer system.
7. Sewer cleaning is important to:
A. Increase pipe corrosion
B. Prevent blockages and maintain flow capacity
,C. Reduce pipe slope
D. Inspect sewer paint
Answer: B - Cleaning prevents solids accumulation that can lead
to blockages and overflows.
8. The most common cause of sewer backups in homes is:
A. Tree root intrusion
B. Industrial discharge
C. High rainfall
D. Normal wastewater flow
Answer: A - Tree roots can infiltrate sewer joints, causing
blockages and backups.
9. What is the purpose of a wet well in a lift station?
A. To treat wastewater
B. To temporarily store wastewater before pumping
C. To separate solids from liquids
D. To filter stormwater
Answer: B - Wet wells provide a holding area so that pumps can
operate efficiently and prevent surges.
10. The type of pump most commonly used in wastewater lift
stations is:
A. Centrifugal pump
B. Reciprocating pump
C. Gear pump
D. Diaphragm pump
Answer: A - Centrifugal pumps are common because they handle
large volumes of wastewater with varying solids content.
11. Properly designed wastewater systems maintain a
minimum velocity in the sewer of approximately:
, A. 0.5 feet per second
B. 2 feet per second
C. 10 feet per second
D. 15 feet per second
Answer: B - A velocity of 2 feet per second is generally sufficient
to keep solids in suspension.
12. Hydrogen sulfide gas in sewers can lead to:
A. Improved flow
B. Corrosion of concrete and metal
C. Cleaner water
D. Reduced odor
Answer: B - H₂S reacts with moisture to form sulfuric acid, which
corrodes pipes and structures.
13. A sewer overflow caused by heavy rain is called a:
A. Dry weather overflow
B. Infiltration overflow
C. Sanitary sewer overflow
D. Combined sewer overflow
Answer: D - Combined sewers carry both sewage and
stormwater; heavy rain can cause them to overflow.
14. A common method for locating leaks in a sewer system is:
A. Dye testing
B. Painting the pipe
C. Installing new pipe
D. Using chlorine tablets
Answer: A - Dye testing helps identify unauthorized connections
and leaks.
Certification Exam Practice Questions
And Correct Answers (Verified
Answers) Plus Rationale 2026 Q&A|
Instant Download Pdf GRADED A+
1. The primary purpose of a wastewater collection system is
to:
A. Provide drinking water
B. Collect and transport wastewater to treatment facilities
C. Treat wastewater on-site
D. Generate electricity
Answer: B - The main function of a collection system is to move
wastewater from homes and businesses to treatment plants.
2. Sanitary sewers are designed to carry:
A. Storm water only
B. Industrial wastewater only
C. Domestic wastewater only
D. Both stormwater and domestic wastewater
Answer: C - Sanitary sewers are intended to carry domestic
wastewater, not stormwater, which is handled by storm sewers.
3. The term "inflow" refers to:
A. Groundwater entering the sewer through cracks
B. Rainwater entering the sewer through illegal connections
C. Industrial waste added to the sewer
,D. Normal wastewater from households
Answer: B - Inflow is water that enters the sewer system from
sources such as roof drains, downspouts, and yard drains.
4. The term "infiltration" refers to:
A. Unauthorized connections to the sewer
B. Groundwater entering sewer pipes through cracks or joints
C. Stormwater entering the sewer from streets
D. Excess wastewater discharged from industries
Answer: B - Infiltration is groundwater that leaks into sewer pipes
through defective joints or cracks.
5. Which material is most commonly used for modern gravity
sewer pipes?
A. Cast iron
B. Clay
C. PVC
D. Wood
Answer: C - PVC is widely used due to its durability, smooth
interior surface, and resistance to corrosion.
6. Manholes in a sewer system are primarily used for:
A. Venting gases only
B. Access for inspection and maintenance
C. Treating wastewater
D. Storing excess flow
Answer: B - Manholes provide access points for inspecting,
cleaning, and maintaining the sewer system.
7. Sewer cleaning is important to:
A. Increase pipe corrosion
B. Prevent blockages and maintain flow capacity
,C. Reduce pipe slope
D. Inspect sewer paint
Answer: B - Cleaning prevents solids accumulation that can lead
to blockages and overflows.
8. The most common cause of sewer backups in homes is:
A. Tree root intrusion
B. Industrial discharge
C. High rainfall
D. Normal wastewater flow
Answer: A - Tree roots can infiltrate sewer joints, causing
blockages and backups.
9. What is the purpose of a wet well in a lift station?
A. To treat wastewater
B. To temporarily store wastewater before pumping
C. To separate solids from liquids
D. To filter stormwater
Answer: B - Wet wells provide a holding area so that pumps can
operate efficiently and prevent surges.
10. The type of pump most commonly used in wastewater lift
stations is:
A. Centrifugal pump
B. Reciprocating pump
C. Gear pump
D. Diaphragm pump
Answer: A - Centrifugal pumps are common because they handle
large volumes of wastewater with varying solids content.
11. Properly designed wastewater systems maintain a
minimum velocity in the sewer of approximately:
, A. 0.5 feet per second
B. 2 feet per second
C. 10 feet per second
D. 15 feet per second
Answer: B - A velocity of 2 feet per second is generally sufficient
to keep solids in suspension.
12. Hydrogen sulfide gas in sewers can lead to:
A. Improved flow
B. Corrosion of concrete and metal
C. Cleaner water
D. Reduced odor
Answer: B - H₂S reacts with moisture to form sulfuric acid, which
corrodes pipes and structures.
13. A sewer overflow caused by heavy rain is called a:
A. Dry weather overflow
B. Infiltration overflow
C. Sanitary sewer overflow
D. Combined sewer overflow
Answer: D - Combined sewers carry both sewage and
stormwater; heavy rain can cause them to overflow.
14. A common method for locating leaks in a sewer system is:
A. Dye testing
B. Painting the pipe
C. Installing new pipe
D. Using chlorine tablets
Answer: A - Dye testing helps identify unauthorized connections
and leaks.
