NPDES Stormwater Compliance Exam
Practice Questions and Correct Answers
(Verified Answers) Plus Rationales 2027
Q&A | Instant Download Pdf
1. What does NPDES stand for?
A. National Pollution Discharge Environmental Standard
B. National Pollutant Discharge Elimination System
C. National Protection and Drainage Enforcement System
D. National Permit Discharge Evaluation Standard
Correct Answer: B
Rationale: NPDES stands for National Pollutant Discharge Elimination System. It is
the federal permitting framework established under the Clean Water Act for
regulating qualifying pollutant discharges to waters of the United States.
2. What is the primary purpose of the NPDES program?
A. To regulate building construction schedules
B. To control municipal tax revenues
C. To eliminate all natural stormwater runoff
D. To regulate qualifying pollutant discharges to waters of the United States
Correct Answer: D
Rationale: The NPDES program provides a permitting mechanism for controlling
qualifying point-source discharges of pollutants to waters of the United States.
3. Which three sources are specifically addressed by EPA's NPDES stormwater
program?
,A. MS4s, construction activities, and industrial activities
B. Drinking-water plants, septic systems, and wetlands
C. Agriculture, irrigation, and groundwater wells
D. Dams, reservoirs, and navigable channels
Correct Answer: A
Rationale: EPA identifies municipal separate storm sewer systems, construction
activities, and industrial activities as the three principal sources addressed by the
NPDES stormwater program.
4. What is an MS4?
A. A combined sewer carrying sanitary and stormwater
B. A wastewater treatment plant
C. A municipal separate storm sewer system
D. A private drinking-water distribution network
Correct Answer: C
Rationale: MS4 stands for Municipal Separate Storm Sewer System. EPA defines
an MS4 as a conveyance or system of conveyances designed or used to collect or
convey stormwater that is not a combined sewer and is not part of a sewage
treatment plant or POTW.
5. What distinguishes an MS4 from a combined sewer system?
A. An MS4 carries only groundwater
B. An MS4 is separate from the sanitary sewer system
C. An MS4 cannot discharge to surface waters
D. An MS4 is used only by private industries
Correct Answer: B
Rationale: A municipal separate storm sewer system is separate from a combined
sewer system. It is designed or used to convey stormwater rather than combining
stormwater and sanitary sewage in the same conveyance.
,6. What is the main purpose of an MS4 Stormwater Management Program
(SWMP)?
A. To reduce pollutant discharges from the MS4
B. To eliminate all municipal drainage systems
C. To regulate drinking-water treatment
D. To replace state water-quality standards
Correct Answer: A
Rationale: Regulated MS4 operators must develop, implement, and enforce
stormwater management programs designed to reduce pollutant discharges from
their sewer systems.
7. Which is a required minimum control measure for regulated small MS4s?
A. Industrial wastewater pretreatment
B. Drinking-water disinfection
C. Construction site runoff control
D. Hazardous-waste incineration
Correct Answer: C
Rationale: EPA's Phase II MS4 framework includes construction site runoff control
as one of the six minimum control measures.
8. Which MS4 minimum control measure addresses unauthorized non-
stormwater flows entering the storm sewer system?
A. Public education and outreach
B. Post-construction runoff control
C. Pollution prevention and good housekeeping
D. Illicit discharge detection and elimination
Correct Answer: D
, Rationale: The illicit discharge detection and elimination minimum control
measure establishes a program for identifying and addressing illicit discharges to
the MS4.
9. Which activity is included in the public education and outreach minimum
control measure?
A. Informing the public about stormwater pollution and prevention
B. Issuing building permits
C. Testing drinking water
D. Approving wastewater treatment plant designs
Correct Answer: A
Rationale: Public education and outreach is intended to increase awareness of
stormwater pollution and encourage behaviors that reduce pollutant discharges.
10. What is the purpose of the public participation/involvement minimum
control measure?
A. To eliminate public access to stormwater information
B. To involve the public in the development and implementation of the MS4
program
C. To replace the MS4 permit
D. To regulate industrial wastewater treatment
Correct Answer: B
Rationale: Public participation and involvement provides opportunities for the
public to participate in appropriate aspects of the stormwater management
program.
11. What is the primary objective of illicit discharge detection and elimination?
A. Increase stormwater flows
B. Identify and eliminate unauthorized discharges to the MS4
Practice Questions and Correct Answers
(Verified Answers) Plus Rationales 2027
Q&A | Instant Download Pdf
1. What does NPDES stand for?
A. National Pollution Discharge Environmental Standard
B. National Pollutant Discharge Elimination System
C. National Protection and Drainage Enforcement System
D. National Permit Discharge Evaluation Standard
Correct Answer: B
Rationale: NPDES stands for National Pollutant Discharge Elimination System. It is
the federal permitting framework established under the Clean Water Act for
regulating qualifying pollutant discharges to waters of the United States.
2. What is the primary purpose of the NPDES program?
A. To regulate building construction schedules
B. To control municipal tax revenues
C. To eliminate all natural stormwater runoff
D. To regulate qualifying pollutant discharges to waters of the United States
Correct Answer: D
Rationale: The NPDES program provides a permitting mechanism for controlling
qualifying point-source discharges of pollutants to waters of the United States.
3. Which three sources are specifically addressed by EPA's NPDES stormwater
program?
,A. MS4s, construction activities, and industrial activities
B. Drinking-water plants, septic systems, and wetlands
C. Agriculture, irrigation, and groundwater wells
D. Dams, reservoirs, and navigable channels
Correct Answer: A
Rationale: EPA identifies municipal separate storm sewer systems, construction
activities, and industrial activities as the three principal sources addressed by the
NPDES stormwater program.
4. What is an MS4?
A. A combined sewer carrying sanitary and stormwater
B. A wastewater treatment plant
C. A municipal separate storm sewer system
D. A private drinking-water distribution network
Correct Answer: C
Rationale: MS4 stands for Municipal Separate Storm Sewer System. EPA defines
an MS4 as a conveyance or system of conveyances designed or used to collect or
convey stormwater that is not a combined sewer and is not part of a sewage
treatment plant or POTW.
5. What distinguishes an MS4 from a combined sewer system?
A. An MS4 carries only groundwater
B. An MS4 is separate from the sanitary sewer system
C. An MS4 cannot discharge to surface waters
D. An MS4 is used only by private industries
Correct Answer: B
Rationale: A municipal separate storm sewer system is separate from a combined
sewer system. It is designed or used to convey stormwater rather than combining
stormwater and sanitary sewage in the same conveyance.
,6. What is the main purpose of an MS4 Stormwater Management Program
(SWMP)?
A. To reduce pollutant discharges from the MS4
B. To eliminate all municipal drainage systems
C. To regulate drinking-water treatment
D. To replace state water-quality standards
Correct Answer: A
Rationale: Regulated MS4 operators must develop, implement, and enforce
stormwater management programs designed to reduce pollutant discharges from
their sewer systems.
7. Which is a required minimum control measure for regulated small MS4s?
A. Industrial wastewater pretreatment
B. Drinking-water disinfection
C. Construction site runoff control
D. Hazardous-waste incineration
Correct Answer: C
Rationale: EPA's Phase II MS4 framework includes construction site runoff control
as one of the six minimum control measures.
8. Which MS4 minimum control measure addresses unauthorized non-
stormwater flows entering the storm sewer system?
A. Public education and outreach
B. Post-construction runoff control
C. Pollution prevention and good housekeeping
D. Illicit discharge detection and elimination
Correct Answer: D
, Rationale: The illicit discharge detection and elimination minimum control
measure establishes a program for identifying and addressing illicit discharges to
the MS4.
9. Which activity is included in the public education and outreach minimum
control measure?
A. Informing the public about stormwater pollution and prevention
B. Issuing building permits
C. Testing drinking water
D. Approving wastewater treatment plant designs
Correct Answer: A
Rationale: Public education and outreach is intended to increase awareness of
stormwater pollution and encourage behaviors that reduce pollutant discharges.
10. What is the purpose of the public participation/involvement minimum
control measure?
A. To eliminate public access to stormwater information
B. To involve the public in the development and implementation of the MS4
program
C. To replace the MS4 permit
D. To regulate industrial wastewater treatment
Correct Answer: B
Rationale: Public participation and involvement provides opportunities for the
public to participate in appropriate aspects of the stormwater management
program.
11. What is the primary objective of illicit discharge detection and elimination?
A. Increase stormwater flows
B. Identify and eliminate unauthorized discharges to the MS4
