International Residential Code (IRC)
Residential Plumbing Examination
RESIDENTIAL PLUMBING
EXAMINATION
2026/2027 Academic Year
Total Questions: 75 Multiple-Choice Questions (MCQ)
Testing Time: 120 Minutes
Format: Computer-Based, Proctored at ICC-Approved Testing Centers
Passing Score: 75% (56/75 Correct)
Question Types: Standard MCQ, SATA, Code Application Scenarios, Pipe Sizing Calculations
Aligned With: IRC Chapter P Provisions, ICC Certification Standards
, EXAMINATION INSTRUCTIONS
1. This examination consists of 75 multiple-choice questions covering foundational residential
plumbing principles, IRC Chapter P provisions, and code compliance applications.
2. Each question has four answer options (A, B, C, D). Select the single best answer unless the
question is explicitly marked as Select-All-That-Apply (SATA).
3. Questions are presented in bold. Correct answers are indicated in bold purple. Detailed rationales
are provided in italic font with a lavender background.
4. The exam is organized into the following core domains: General Regulations, Water Supply &
Distribution, DWV Systems, Fixtures & Appliances, Water Heaters, Storm Drainage, Fuel Gas Piping,
Testing & Inspection, Materials & Safety Compliance, and Scenario-Based Application.
5. Focus on evidence-based residential plumbing protocols, IRC Chapter P regulatory compliance
application, and professional judgment aligned with ICC certification standards.
6. Pace yourself to complete all questions within the 120-minute testing period.
7. A passing score of 75% (56 correct answers out of 75) is typically required for IRC Residential
Plumbing certification eligibility per licensing board policy.
Domain Distribution:
General Regulations & Administrative Provisions (Q1–Q8): 8 Questions
Water Supply & Distribution Systems (Q9–Q17): 9 Questions
Drain, Waste, and Vent (DWV) Systems (Q18–Q27): 10 Questions
Fixtures, Fixture Fittings & Appliances (Q28–Q34): 7 Questions
Water Heaters & Hot Water Systems (Q35–Q42): 8 Questions
Storm Drainage & Site Plumbing (Q43–Q48): 6 Questions
Fuel Gas Piping — IRC Chapter G Integration (Q49–Q55): 7 Questions
Testing, Inspection & Acceptance (Q56–Q61): 6 Questions
Materials, Standards & Safety Compliance (Q62–Q68): 7 Questions
Scenario-Based Application (Q69–Q75): 7 Questions
, General Regulations & Administrative Provisions
Q1. According to IRC Chapter P, the scope of the plumbing provisions applies to which type
of construction?
A. Commercial buildings exceeding three stories
B. One- and two-family dwellings and townhouses not more than three stories above
grade
C. Multi-family residential buildings with four or more units
D. Industrial facilities with process piping
Correct Answer: B
Rationale: IRC Chapter P specifically applies to plumbing systems in one- and two-family dwellings
and townhouses that are not more than three stories above grade plane in height. This scope limitation
is defined in IRC Section P101.2 and distinguishes the IRC from the International Plumbing Code (IPC),
which covers commercial and multi-family buildings. The IRC's residential focus means its provisions
are tailored to the plumbing needs and safety requirements of single-family and duplex construction,
providing prescriptive requirements that simplify design and installation for residential applications.
Q2. Before commencing any plumbing installation covered by IRC Chapter P, which of the
following is required?
A. A verbal approval from the local utility company
B. A permit obtained from the building official
C. A notarized statement from the property owner
D. Notification to the fire marshal only
Correct Answer: B
Rationale: IRC Section P101.2 requires that any plumbing installation, alteration, or repair covered
by the code must not commence until a permit has been obtained from the building official. The permit
process ensures that proposed work is reviewed for code compliance before construction begins, and it
establishes the framework for required inspections. Verbal approvals, notarized statements, and fire
marshal notifications do not satisfy the legal permit requirement. The permit application typically
requires construction documents, specifications, and plans sufficient to demonstrate compliance with
IRC provisions.
Q3. Under the IRC, which definition best describes a 'plumbing fixture'?
A. Any pipe or fitting that carries water or waste
B. A receptacle or device that is connected to a water supply system or discharges to a
drainage system and is installed in a plumbing system
C. A mechanical device used only for water heating
D. An underground pipe used for storm drainage
Correct Answer: B
Rationale: The IRC defines a plumbing fixture as a receptacle or device that is either connected to a
water supply system or discharges to a drainage system, or both, and is installed as part of a plumbing
system. This definition encompasses water closets, lavatories, bathtubs, showers, sinks, and similar
devices. Pipes and fittings are components of the plumbing system but are not themselves fixtures.
Water heaters are appliances, not fixtures in the code definition, and underground storm drainage pipes
are part of the drainage system rather than fixtures.
Q4. When a proposed plumbing installation uses materials or methods not specifically
prescribed by the IRC, the building official may approve the alternate provided that:
A. The alternate is less expensive than code-prescribed materials
B. The proposed alternate is at least equivalent to that prescribed, complies with the
intent of the code, and is satisfactory for the intended purpose
Residential Plumbing Examination
RESIDENTIAL PLUMBING
EXAMINATION
2026/2027 Academic Year
Total Questions: 75 Multiple-Choice Questions (MCQ)
Testing Time: 120 Minutes
Format: Computer-Based, Proctored at ICC-Approved Testing Centers
Passing Score: 75% (56/75 Correct)
Question Types: Standard MCQ, SATA, Code Application Scenarios, Pipe Sizing Calculations
Aligned With: IRC Chapter P Provisions, ICC Certification Standards
, EXAMINATION INSTRUCTIONS
1. This examination consists of 75 multiple-choice questions covering foundational residential
plumbing principles, IRC Chapter P provisions, and code compliance applications.
2. Each question has four answer options (A, B, C, D). Select the single best answer unless the
question is explicitly marked as Select-All-That-Apply (SATA).
3. Questions are presented in bold. Correct answers are indicated in bold purple. Detailed rationales
are provided in italic font with a lavender background.
4. The exam is organized into the following core domains: General Regulations, Water Supply &
Distribution, DWV Systems, Fixtures & Appliances, Water Heaters, Storm Drainage, Fuel Gas Piping,
Testing & Inspection, Materials & Safety Compliance, and Scenario-Based Application.
5. Focus on evidence-based residential plumbing protocols, IRC Chapter P regulatory compliance
application, and professional judgment aligned with ICC certification standards.
6. Pace yourself to complete all questions within the 120-minute testing period.
7. A passing score of 75% (56 correct answers out of 75) is typically required for IRC Residential
Plumbing certification eligibility per licensing board policy.
Domain Distribution:
General Regulations & Administrative Provisions (Q1–Q8): 8 Questions
Water Supply & Distribution Systems (Q9–Q17): 9 Questions
Drain, Waste, and Vent (DWV) Systems (Q18–Q27): 10 Questions
Fixtures, Fixture Fittings & Appliances (Q28–Q34): 7 Questions
Water Heaters & Hot Water Systems (Q35–Q42): 8 Questions
Storm Drainage & Site Plumbing (Q43–Q48): 6 Questions
Fuel Gas Piping — IRC Chapter G Integration (Q49–Q55): 7 Questions
Testing, Inspection & Acceptance (Q56–Q61): 6 Questions
Materials, Standards & Safety Compliance (Q62–Q68): 7 Questions
Scenario-Based Application (Q69–Q75): 7 Questions
, General Regulations & Administrative Provisions
Q1. According to IRC Chapter P, the scope of the plumbing provisions applies to which type
of construction?
A. Commercial buildings exceeding three stories
B. One- and two-family dwellings and townhouses not more than three stories above
grade
C. Multi-family residential buildings with four or more units
D. Industrial facilities with process piping
Correct Answer: B
Rationale: IRC Chapter P specifically applies to plumbing systems in one- and two-family dwellings
and townhouses that are not more than three stories above grade plane in height. This scope limitation
is defined in IRC Section P101.2 and distinguishes the IRC from the International Plumbing Code (IPC),
which covers commercial and multi-family buildings. The IRC's residential focus means its provisions
are tailored to the plumbing needs and safety requirements of single-family and duplex construction,
providing prescriptive requirements that simplify design and installation for residential applications.
Q2. Before commencing any plumbing installation covered by IRC Chapter P, which of the
following is required?
A. A verbal approval from the local utility company
B. A permit obtained from the building official
C. A notarized statement from the property owner
D. Notification to the fire marshal only
Correct Answer: B
Rationale: IRC Section P101.2 requires that any plumbing installation, alteration, or repair covered
by the code must not commence until a permit has been obtained from the building official. The permit
process ensures that proposed work is reviewed for code compliance before construction begins, and it
establishes the framework for required inspections. Verbal approvals, notarized statements, and fire
marshal notifications do not satisfy the legal permit requirement. The permit application typically
requires construction documents, specifications, and plans sufficient to demonstrate compliance with
IRC provisions.
Q3. Under the IRC, which definition best describes a 'plumbing fixture'?
A. Any pipe or fitting that carries water or waste
B. A receptacle or device that is connected to a water supply system or discharges to a
drainage system and is installed in a plumbing system
C. A mechanical device used only for water heating
D. An underground pipe used for storm drainage
Correct Answer: B
Rationale: The IRC defines a plumbing fixture as a receptacle or device that is either connected to a
water supply system or discharges to a drainage system, or both, and is installed as part of a plumbing
system. This definition encompasses water closets, lavatories, bathtubs, showers, sinks, and similar
devices. Pipes and fittings are components of the plumbing system but are not themselves fixtures.
Water heaters are appliances, not fixtures in the code definition, and underground storm drainage pipes
are part of the drainage system rather than fixtures.
Q4. When a proposed plumbing installation uses materials or methods not specifically
prescribed by the IRC, the building official may approve the alternate provided that:
A. The alternate is less expensive than code-prescribed materials
B. The proposed alternate is at least equivalent to that prescribed, complies with the
intent of the code, and is satisfactory for the intended purpose
