Wastewater NPDES permit conditions practice questions
20 free practice questions from 40 CFR 122.2 and 122.41. Each answer is explained and linked to the rule it comes from.
Wastewater NPDES permit conditions
20 questions across 7 topics. After each answer you see why it is right, with a link to the official source.
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Definitions: discharges and limitations
1. How does 122.2 say an average weekly discharge limitation is calculated?
- A. The highest single daily discharge measured during the week
- B. The sum of all daily discharges measured during a calendar week divided by the number of daily discharges measured during that week
- C. The sum of daily discharges over any 7 consecutive days divided by 7, whether or not each day was sampled
- D. The total of all daily discharges measured during the week
Show answer
Answer: B. The sum of all daily discharges measured during a calendar week divided by the number of daily discharges measured during that week
It is "the highest allowable average of "daily discharges" over a calendar week, calculated as the sum of all "daily discharges" measured during a calendar week divided by the number of "daily discharges" measured during that week."
2. What does 122.2 define a maximum daily discharge limitation to be?
- A. The highest allowable average of daily discharges over a calendar month
- B. The highest instantaneous reading allowed in any hour
- C. The total discharge allowed over a calendar week
- D. The highest allowable daily discharge
Show answer
Answer: D. The highest allowable daily discharge
"Maximum daily discharge limitation means the highest allowable "daily discharge.""
3. How does 122.2 define an indirect discharger?
- A. A nondomestic discharger introducing pollutants to a publicly owned treatment works
- B. Any discharger whose pipe is owned by a municipality
- C. A POTW that discharges through a combined sewer system
- D. A facility whose discharge reaches surface water only through ground water
Show answer
Answer: A. A nondomestic discharger introducing pollutants to a publicly owned treatment works
"Indirect discharger means a nondomestic discharger introducing "pollutants" to a "publicly owned treatment works."" The definition of discharge of a pollutant "does not include an addition of pollutants by any "indirect discharger.""
Definitions: facilities, sludge and program terms
4. How does 122.2 describe what the "standards for sewage sludge use or disposal" govern?
- A. Only the design and construction of sewage sludge treatment units at POTWs
- B. Only sewage sludge that is sold or given away in a bag or other container
- C. Minimum requirements for sludge quality, management practices, and monitoring and reporting applicable to sewage sludge or the use or disposal of sewage sludge by any person
- D. The BOD5 and SS effluent limitations in a POTW's discharge
Show answer
Answer: C. Minimum requirements for sludge quality, management practices, and monitoring and reporting applicable to sewage sludge or the use or disposal of sewage sludge by any person
"Standards for sewage sludge use or disposal means the regulations promulgated pursuant to section 405(d) of the CWA which govern minimum requirements for sludge quality, management practices, and monitoring and reporting applicable to sewage sludge or the use or disposal of sewage sludge by any person."
5. Under 122.2, who does "Director" normally mean when there is an approved State program?
- A. The State Director
- B. The EPA Administrator in every case
- C. The superintendent of the POTW
- D. The Regional Administrator in every case
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Answer: A. The State Director
"When there is an approved State program, "Director" normally means the State Director." The definition adds that "in some circumstances, however, EPA retains the authority to take certain actions even when there is an approved State program."
6. Under 122.2, which of these is part of a "treatment works treating domestic sewage," regardless of ownership?
- A. A septic tank serving a single home
- B. A process wastewater sewer inside a factory
- C. Land dedicated for the disposal of sewage sludge
- D. A storm water outfall from a parking lot
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Answer: C. Land dedicated for the disposal of sewage sludge
The term covers "a POTW or any other sewage sludge or waste water treatment devices or systems, regardless of ownership (including federal facilities), used in the storage, treatment, recycling, and reclamation of municipal or domestic sewage, including land dedicated for the disposal of sewage sludge." It "does not include septic tanks or similar devices."
Duty to comply and general conditions
7. Under 122.41(a)(1), when must a permittee comply with section 307(a) toxic pollutant effluent standards and section 405(d) sewage sludge standards?
- A. Only after the permit has been modified to include them
- B. Within the time provided in the regulations that establish them, even if the permit has not yet been modified to incorporate the requirement
- C. At the next permit renewal
- D. Within 14 days after the Director sends written notice
Show answer
Answer: B. Within the time provided in the regulations that establish them, even if the permit has not yet been modified to incorporate the requirement
The permittee must comply "within the time provided in the regulations that establish these standards or prohibitions or standards for sewage sludge use or disposal, even if the permit has not yet been modified to incorporate the requirement."
Source: eCFR: 40 CFR 122.41, Conditions applicable to all permits (as of Nov 4, 2026)
8. A permittee argues in an enforcement action that it would have had to halt or reduce the permitted activity to stay in compliance. What does 122.41(c) say about that argument?
- A. It is an affirmative defense if supported by operating logs
- B. It is a defense only for POTWs
- C. It is a defense if the Director was told within 24 hours
- D. It shall not be a defense
Show answer
Answer: D. It shall not be a defense
"It shall not be a defense for a permittee in an enforcement action that it would have been necessary to halt or reduce the permitted activity in order to maintain compliance with the conditions of this permit."
Source: eCFR: 40 CFR 122.41, Conditions applicable to all permits (as of Nov 4, 2026)
9. Under 122.41(e), when does the proper operation and maintenance condition require a permittee to operate back-up or auxiliary facilities it has installed?
- A. At all times, as long as the permit is in effect
- B. During every wet weather event
- C. Whenever the Director inspects the facility
- D. Only when the operation is necessary to achieve compliance with the conditions of the permit
Show answer
Answer: D. Only when the operation is necessary to achieve compliance with the conditions of the permit
"This provision requires the operation of back-up or auxiliary facilities or similar systems which are installed by a permittee only when the operation is necessary to achieve compliance with the conditions of the permit."
Source: eCFR: 40 CFR 122.41, Conditions applicable to all permits (as of Nov 4, 2026)
Inspection, monitoring and records
10. Instead of the general 3-year retention period, which category of records does 122.41(j)(2) single out for retention of at least five years (or longer as required by 40 CFR part 503)?
- A. Records of monitoring information required by the permit related to the permittee's sewage sludge use and disposal activities
- B. Original strip chart recordings for continuous monitoring instrumentation
- C. Calibration and maintenance records
- D. Records of data used to complete the permit application
Show answer
Answer: A. Records of monitoring information required by the permit related to the permittee's sewage sludge use and disposal activities
Records "related to the permittee's sewage sludge use and disposal activities" are kept "for a period of at least five years (or longer as required by 40 CFR part 503)"; the other monitoring records, including calibration and maintenance records and strip charts, are kept "for a period of at least 3 years".
Source: eCFR: 40 CFR 122.41, Conditions applicable to all permits (as of Nov 4, 2026)
11. Under 122.41(j)(2), who may extend the 3-year period for keeping monitoring records, copies of reports and application data, and when?
- A. The permittee, by sending notice to the Director
- B. Nobody; the period cannot be extended
- C. The Director, by request, at any time
- D. The Director, but only when the permit is reissued
Show answer
Answer: C. The Director, by request, at any time
These records are kept "for a period of at least 3 years from the date of the sample, measurement, report or application." The paragraph adds: "This period may be extended by request of the Director at any time."
Source: eCFR: 40 CFR 122.41, Conditions applicable to all permits (as of Nov 4, 2026)
12. Under 122.41(i), what must the Director or an authorized representative present before entering and inspecting the permittee's premises?
- A. At least 48 hours of advance written notice
- B. Credentials and other documents as may be required by law
- C. Written consent from the facility's operator in charge
- D. A copy of the facility's most recent DMR
Show answer
Answer: B. Credentials and other documents as may be required by law
The permittee must allow the Director or an authorized representative, "upon presentation of credentials and other documents as may be required by law," to enter, have access to and copy records, inspect, and sample or monitor.
Source: eCFR: 40 CFR 122.41, Conditions applicable to all permits (as of Nov 4, 2026)
Reporting requirements
13. Under 122.41(l)(6)(i), the report on noncompliance which may endanger health or the environment shall contain several items. Which of these is one of them?
- A. Steps taken or planned to reduce, eliminate, and prevent reoccurrence of the noncompliance
- B. The name and certification number of the operator on duty
- C. A cost estimate for the repairs
- D. Copies of laboratory bench sheets for the previous 30 days
Show answer
Answer: A. Steps taken or planned to reduce, eliminate, and prevent reoccurrence of the noncompliance
"The report shall contain a description of the noncompliance and its cause; the period of noncompliance, including exact dates and times)," the anticipated time it is expected to continue if not corrected, "and steps taken or planned to reduce, eliminate, and prevent reoccurrence of the noncompliance."
Source: eCFR: 40 CFR 122.41, Conditions applicable to all permits (as of Nov 4, 2026)
14. Under 122.41(l)(7), when must a permittee report instances of noncompliance that were not reported under paragraphs (l)(4), (5), and (6)?
- A. Orally within 24 hours of becoming aware of them
- B. At the time monitoring reports are submitted
- C. Only in the next application for permit renewal
- D. Never, if the noncompliance was corrected before the next sample
Show answer
Answer: B. At the time monitoring reports are submitted
"The permittee shall report all instances of noncompliance not reported under paragraphs (l)(4), (5), and (6) of this section, at the time monitoring reports are submitted." "The reports shall contain the information listed in paragraph (l)(6)."
Source: eCFR: 40 CFR 122.41, Conditions applicable to all permits (as of Nov 4, 2026)
15. What deadline does 122.41(l)(5) set for reports of compliance or noncompliance with interim and final requirements in a permit's compliance schedule?
- A. Orally within 24 hours of each schedule date
- B. Within 5 days of each schedule date
- C. With the next annual permit renewal application
- D. No later than 14 days following each schedule date
Show answer
Answer: D. No later than 14 days following each schedule date
Such reports "shall be submitted no later than 14 days following each schedule date."
Source: eCFR: 40 CFR 122.41, Conditions applicable to all permits (as of Nov 4, 2026)
Bypass
16. Under 122.41(m)(2), a permittee may allow a bypass that does not cause effluent limitations to be exceeded, but only if the bypass also meets which condition?
- A. It lasts less than 24 hours
- B. The Director approved it in writing at least ten days ahead
- C. It is for essential maintenance to assure efficient operation
- D. It occurs only during wet weather
Show answer
Answer: C. It is for essential maintenance to assure efficient operation
"The permittee may allow any bypass to occur which does not cause effluent limitations to be exceeded, but only if it also is for essential maintenance to assure efficient operation." "These bypasses are not subject to the provisions of paragraphs (m)(3) and (m)(4) of this section."
Source: eCFR: 40 CFR 122.41, Conditions applicable to all permits (as of Nov 4, 2026)
17. One condition for a bypass to escape the prohibition in 122.41(m)(4)(i) is that there were no feasible alternatives. When does that rule say this condition is not satisfied?
- A. When the bypass lasted longer than 24 hours
- B. When the permittee gave notice less than ten days ahead
- C. When adequate back-up equipment should have been installed in the exercise of reasonable engineering judgment to prevent a bypass during normal equipment downtime or preventive maintenance
- D. When the bypass was caused by wet weather
Show answer
Answer: C. When adequate back-up equipment should have been installed in the exercise of reasonable engineering judgment to prevent a bypass during normal equipment downtime or preventive maintenance
"This condition is not satisfied if adequate back-up equipment should have been installed in the exercise of reasonable engineering judgment to prevent a bypass which occurred during normal periods of equipment downtime or preventive maintenance".
Source: eCFR: 40 CFR 122.41, Conditions applicable to all permits (as of Nov 4, 2026)
Upset
18. Under 122.41(n)(2), what status does a determination made during administrative review of claims that noncompliance was caused by upset have, before an action for noncompliance?
- A. It is not final administrative action subject to judicial review
- B. It is final administrative action subject to judicial review
- C. It is final administrative action, but only for POTWs
- D. It becomes final administrative action subject to judicial review once the Director signs it
Show answer
Answer: A. It is not final administrative action subject to judicial review
122.41(n)(2) states: "No determination made during administrative review of claims that noncompliance was caused by upset, and before an action for noncompliance, is final administrative action subject to judicial review."
Source: eCFR: 40 CFR 122.41, Conditions applicable to all permits (as of Nov 4, 2026)
19. A permittee wants to establish the affirmative defense of upset. Under 122.41(n)(3), which of these must it demonstrate through properly signed, contemporaneous operating logs, or other relevant evidence?
- A. That the upset lasted less than 24 hours
- B. That no Industrial User discharged to the facility during the upset
- C. That the facility had no other upset during the permit term
- D. That the permitted facility was at the time being properly operated
Show answer
Answer: D. That the permitted facility was at the time being properly operated
The permittee "shall demonstrate, through properly signed, contemporaneous operating logs, or other relevant evidence that", among other things, "The permitted facility was at the time being properly operated". It must also show that "An upset occurred and that the permittee can identify the cause(s) of the upset", that it gave the 24-hour notice, and that it complied with any required remedial measures.
Source: eCFR: 40 CFR 122.41, Conditions applicable to all permits (as of Nov 4, 2026)
20. A permit limit was exceeded during an exceptional incident. Under the definition of upset in 122.41(n)(1), noncompliance caused by which of these is left out of an upset?
- A. Factors beyond the reasonable control of the permittee
- B. Lack of preventive maintenance
- C. An unintentional and temporary event
- D. An exceptional incident
Show answer
Answer: B. Lack of preventive maintenance
Upset means "an exceptional incident in which there is unintentional and temporary noncompliance with technology based permit effluent limitations because of factors beyond the reasonable control of the permittee." But "An upset does not include noncompliance to the extent caused by operational error, improperly designed treatment facilities, inadequate treatment facilities, lack of preventive maintenance, or careless or improper operation."
Source: eCFR: 40 CFR 122.41, Conditions applicable to all permits (as of Nov 4, 2026)