Water system auditing MCQs With Answer

Introduction: Water system auditing MCQs With Answer is a focussed resource tailored for M.Pharm students preparing for exams and practical audits in pharmaceutical water systems. This blog covers critical concepts such as system design, validation, monitoring (microbial, TOC, conductivity), sanitization, biofilm control, sampling strategies, regulatory expectations and deviation handling. The MCQs are crafted to test both theoretical knowledge and practical decision-making used during audits and compliance assessments. Each question mirrors real-world audit scenarios and regulatory nuances to help students build competence in evaluating water quality, interpreting trends, planning corrective actions and documenting findings in accordance with pharmacopeial and GMP standards.

Q1. What is the primary purpose of a water system audit in a pharmaceutical facility?

• To identify the cheapest maintenance vendors
• To verify that the water system design, operation and monitoring meet regulatory and pharmacopeial requirements
• To test staff knowledge of unrelated laboratory equipment
• To replace all filters regardless of condition

Correct Answer: To verify that the water system design, operation and monitoring meet regulatory and pharmacopeial requirements

Q2. Which sampling strategy is most appropriate to detect localized contamination or biofilm in a distribution loop?

• Single central sample at the storage tank
• Random bulk sampling from any convenient tap
• Defined first-draw samples from multiple distal points and stagnation points
• Composite sample mixed from several sites

Correct Answer: Defined first-draw samples from multiple distal points and stagnation points

Q3. During an audit, which of the following is a critical documentation element for water system validation?

• Handwritten notes with no signatures
• Installation, operational and performance qualification (IQ/OQ/PQ) reports with acceptance criteria and raw data
• Only a verbal confirmation from the maintenance engineer
• A generic vendor brochure

Correct Answer: Installation, operational and performance qualification (IQ/OQ/PQ) reports with acceptance criteria and raw data

Q4. What does trending of microbial and chemical parameters help to detect in a water system audit?

• Immediate repair schedule for non-critical items
• Long-term shifts, early signs of system deterioration or recurring excursions
• Which brand of disinfectant is cheapest
• Staff attendance patterns

Correct Answer: Long-term shifts, early signs of system deterioration or recurring excursions

Q5. Which parameter is most useful for rapid online detection of organic contamination in high-purity water?

• Total viable count (TVC)
• Total organic carbon (TOC)
• Coliform count
• pH

Correct Answer: Total organic carbon (TOC)

Q6. In an audit, finding repeated microbial excursions at a distal tap most likely indicates:

• Inadequate training records in a different department
• Design or hydraulic issue causing stagnation, biofilm formation or inadequate sanitization at that point
• Faulty TOC analyzer in the central lab
• Overuse of the tap by operators

Correct Answer: Design or hydraulic issue causing stagnation, biofilm formation or inadequate sanitization at that point

Q7. Which of the following disinfectants is typically used for hot water sanitization in pharmaceutical distribution loops?

• Bleach at ambient temperature only
• Hot water (>80°C) thermal sanitization without chemical additive
• Peracetic acid at room temperature without heat
• Isopropyl alcohol as a circulating sanitizer

Correct Answer: Hot water (>80°C) thermal sanitization without chemical additive

Q8. What is the audit significance of filter integrity testing for point-of-use filters?

• It is optional and not documented
• It ensures filters are installed correctly and retain microbial barriers as specified
• It only checks aesthetic clarity of the filter housing
• It replaces routine microbiological monitoring

Correct Answer: It ensures filters are installed correctly and retain microbial barriers as specified

Q9. Which regulatory expectation is important when a water system change is proposed?

• Implement change immediately and document later
• Perform risk assessment, change control with validation or justification before implementation
• Only inform the vendor
• Replace system components without impact assessment

Correct Answer: Perform risk assessment, change control with validation or justification before implementation

Q10. During an audit, what is the role of action and alert limits for routine monitoring?

• They are used to delay any corrective action
• Alert limits trigger investigation; action limits require corrective and preventive actions to restore control
• They are only recommendations with no follow-up
• They are used solely for internal reporting and not for compliance

Correct Answer: Alert limits trigger investigation; action limits require corrective and preventive actions to restore control

Q11. Which method is most appropriate to demonstrate removal of endotoxin or pyrogens during system validation?

• Only visual inspection of the system
• Conducting validated sterilizing-grade filtration or demonstrating thermal inactivation with supporting data
• Measuring conductivity alone
• Interviewing operators about cleaning frequency

Correct Answer: Conducting validated sterilizing-grade filtration or demonstrating thermal inactivation with supporting data

Q12. What is the key purpose of conducting a distribution loop challenge test during qualification?

• To measure the loop’s energy consumption
• To assess the system’s ability to recover after microbial or chemical challenge and demonstrate sanitization efficacy
• To calibrate lab balances
• To train cleaning staff on sampling techniques

Correct Answer: To assess the system’s ability to recover after microbial or chemical challenge and demonstrate sanitization efficacy

Q13. In an audit report, a major observation related to water quality would most likely be issued when:

• Minor paperwork is missing but water meets all specifications
• Critical parameters fail specification and product safety or patient risk is possible
• There is a cosmetic scratch on a storage tank
• Operator uniforms are slightly untidy

Correct Answer: Critical parameters fail specification and product safety or patient risk is possible

Q14. Which monitoring frequency is considered best practice for critical parameters like TOC and conductivity in a tightly controlled water-for-injection (WFI) system?

• Once per year
• Continuous online monitoring with alarms and periodic laboratory confirmation
• Only when operators suspect a problem
• Monthly manual measurements

Correct Answer: Continuous online monitoring with alarms and periodic laboratory confirmation

Q15. How should an auditor evaluate corrective actions after a microbial excursion?

• Accept any action as long as it was completed quickly
• Assess root cause analysis, adequacy of corrective and preventive actions (CAPA), verification and trending to confirm effectiveness
• Require replacement of the entire system for every excursion
• Ignore documentation if results return within limits later

Correct Answer: Assess root cause analysis, adequacy of corrective and preventive actions (CAPA), verification and trending to confirm effectiveness

Q16. Which of the following is a critical audit check related to water storage tanks?

• Color of the paint on the tank
• Tank design to avoid dead legs, accessibility for cleaning and presence of sterile vents or filters where required
• Whether the tank is located next to HR offices
• Brand of the tank manufacturer regardless of certification

Correct Answer: Tank design to avoid dead legs, accessibility for cleaning and presence of sterile vents or filters where required

Q17. An auditor finds inconsistent sample labeling and chain-of-custody records. What is the most appropriate classification?

• No significance, ignore it
• Major finding because it undermines sample integrity and data reliability
• Cosmetic finding
• Minor observation with no required action

Correct Answer: Major finding because it undermines sample integrity and data reliability

Q18. Why is biofilm formation a particular concern in pharmaceutical water systems?

• Biofilms improve taste of water
• Biofilms protect microbes from sanitization, cause persistent contamination and can release endotoxins or organisms intermittently
• Biofilms only occur in non-pharma systems
• Biofilms reduce conductivity making water purer

Correct Answer: Biofilms protect microbes from sanitization, cause persistent contamination and can release endotoxins or organisms intermittently

Q19. Which documentation is essential to demonstrate compliance for routine water sampling during an audit?

• Sampling procedures, site maps, sampling logs, chain-of-custody, analytical methods and trend reports
• Only verbal confirmations of sampling
• Pictures of sampling personnel only
• Invoice from the water supplier

Correct Answer: Sampling procedures, site maps, sampling logs, chain-of-custody, analytical methods and trend reports

Q20. When evaluating a water system during a regulatory inspection, what is the significance of system change history and trending records?

• They are irrelevant to current performance
• They help assess historical performance, impact of modifications, recurring issues and the effectiveness of CAPAs
• They are only used for marketing purposes
• They replace the need for current testing

Correct Answer: They help assess historical performance, impact of modifications, recurring issues and the effectiveness of CAPAs

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