IICRC MRS (Mold Remediation Specialist)
Exam Questions and Answers |Fall
2025/2026 Update | 100% Correct
SECTION I — Principles of Mold Remediation
1. What is the primary purpose of moisture control in mold
remediation?
A. To kill mold spores
B. To prevent future mold growth
C. To bleach stained surfaces
D. To sanitize occupant belongings
Answer: B
Rationale: Mold requires moisture to grow. Without controlling
moisture sources, remediation may fail because mold will return
even after removal.
2. According to IICRC S520, what relative humidity (RH) level is
generally acceptable to inhibit mold growth in most
environments?
A. Below 30%
B. 30–40%
C. Below 60%
D. Above 70%
,Answer: C
Rationale: Keeping RH below ~60% reduces the likelihood of active
mold growth in most environments.
3. Which of the following is NOT a biological requirement for
mold growth?
A. Nutrient source
B. Light
C. Moisture
D. Suitable temperature
Answer: B
Rationale: Mold does not require light to grow; nutrients, moisture,
and appropriate temperatures are the key factors.
4. The purpose of containment in mold remediation is to:
A. Trap spores in the work area
B. Sterilize all surfaces
C. Increase airflow
D. Reduce structural drying
Answer: A
Rationale: Containment limits spore spread to unaffected areas
during remediation.
5. Air movers are primarily used to:
A. Disinfect surfaces
B. Reduce airborne spores
,C. Enhance drying
D. Create negative pressure
Answer: C
Rationale: Air movers help dry wet materials by increasing
evaporation.
SECTION II — Assessment & Planning (11–20)
11. What is the first step in a mold remediation project?
A. Apply biocide
B. Conduct a thorough assessment
C. Remove visible mold
D. Install containment
Answer: B
Rationale: A proper assessment identifies the extent of
contamination, moisture sources, and planning needs before any
remediation begins.
12. Which instrument is most useful for detecting hidden
moisture?
A. Thermometer
B. Moisture meter
C. Light meter
D. Barometer
Answer: B
Rationale: Moisture meters detect moisture levels within building
materials, essential for identifying hidden wet spots.
, 13. A baseline environmental reading in mold work refers to:
A. Post-remediation outcomes
B. Initial conditions before work begins
C. Final surface sampling
D. ERMI score
Answer: B
Rationale: Baseline readings document conditions before
remediation, providing a reference point.
14. Which of the following should be included in a remediation
work plan?
A. Scope of work
B. Containment procedures
C. Personal protective equipment (PPE) requirements
D. All of the above
Answer: D
Rationale: A comprehensive plan outlines scope, containment,
PPE, waste disposal, and more.
15. An occupant questionnaire helps identify:
A. Moisture problems
B. Presence of hazardous chemicals
C. Health complaints related to mold
D. Past pest infestations
Exam Questions and Answers |Fall
2025/2026 Update | 100% Correct
SECTION I — Principles of Mold Remediation
1. What is the primary purpose of moisture control in mold
remediation?
A. To kill mold spores
B. To prevent future mold growth
C. To bleach stained surfaces
D. To sanitize occupant belongings
Answer: B
Rationale: Mold requires moisture to grow. Without controlling
moisture sources, remediation may fail because mold will return
even after removal.
2. According to IICRC S520, what relative humidity (RH) level is
generally acceptable to inhibit mold growth in most
environments?
A. Below 30%
B. 30–40%
C. Below 60%
D. Above 70%
,Answer: C
Rationale: Keeping RH below ~60% reduces the likelihood of active
mold growth in most environments.
3. Which of the following is NOT a biological requirement for
mold growth?
A. Nutrient source
B. Light
C. Moisture
D. Suitable temperature
Answer: B
Rationale: Mold does not require light to grow; nutrients, moisture,
and appropriate temperatures are the key factors.
4. The purpose of containment in mold remediation is to:
A. Trap spores in the work area
B. Sterilize all surfaces
C. Increase airflow
D. Reduce structural drying
Answer: A
Rationale: Containment limits spore spread to unaffected areas
during remediation.
5. Air movers are primarily used to:
A. Disinfect surfaces
B. Reduce airborne spores
,C. Enhance drying
D. Create negative pressure
Answer: C
Rationale: Air movers help dry wet materials by increasing
evaporation.
SECTION II — Assessment & Planning (11–20)
11. What is the first step in a mold remediation project?
A. Apply biocide
B. Conduct a thorough assessment
C. Remove visible mold
D. Install containment
Answer: B
Rationale: A proper assessment identifies the extent of
contamination, moisture sources, and planning needs before any
remediation begins.
12. Which instrument is most useful for detecting hidden
moisture?
A. Thermometer
B. Moisture meter
C. Light meter
D. Barometer
Answer: B
Rationale: Moisture meters detect moisture levels within building
materials, essential for identifying hidden wet spots.
, 13. A baseline environmental reading in mold work refers to:
A. Post-remediation outcomes
B. Initial conditions before work begins
C. Final surface sampling
D. ERMI score
Answer: B
Rationale: Baseline readings document conditions before
remediation, providing a reference point.
14. Which of the following should be included in a remediation
work plan?
A. Scope of work
B. Containment procedures
C. Personal protective equipment (PPE) requirements
D. All of the above
Answer: D
Rationale: A comprehensive plan outlines scope, containment,
PPE, waste disposal, and more.
15. An occupant questionnaire helps identify:
A. Moisture problems
B. Presence of hazardous chemicals
C. Health complaints related to mold
D. Past pest infestations
