Louisiana Plumbing Contractor Exam
Practice Questions And Correct Answers
(Verified Answers) Plus Rationale 2027
Q&A| Instant Download Pdf.
1. In Louisiana, which state classification most directly covers the
construction, installation, maintenance, or repair of potable and non-
potable water and sewer systems within a building or house?
A. Mechanical Class 6
B. Electrical Class 5
C. Plumbing Class 7
D. Building Construction Class 1
Rationale: Plumbing is classified as Major Classification 7 in Louisiana and
covers potable and non-potable tap water and sewer-water systems within
building structures or houses.
2. Under Louisiana contractor licensing requirements, when does
plumbing work generally require a state contractor license based on
the value of the work?
A. When the value exceeds $1,000
B. When the value exceeds $5,000
C. When the value exceeds $10,000
D. Only when the value exceeds $50,000
,Rationale: Louisiana identifies plumbing as work requiring contractor
licensure when the value of the plumbing work exceeds $10,000.
3. Which organization administers the licensing and regulation of
plumbing professionals in Louisiana?
A. Louisiana State Licensing Board for Contractors only
B. Louisiana Department of Transportation and Development
C. State Plumbing Board of Louisiana
D. Louisiana Department of Revenue
Rationale: The State Plumbing Board of Louisiana regulates plumbers and
administers plumbing licenses and examinations, while contractor
licensing responsibilities can also involve the Louisiana State Licensing
Board for Contractors.
4. Which license generally represents the highest level of individual
plumbing licensure administered by the State Plumbing Board of
Louisiana?
A. Apprentice plumber
B. Tradesman plumber
C. Journeyman plumber
D. Master plumber
Rationale: The master plumber license is the highest principal plumbing
trade license and requires qualifying experience or credentials and
successful examination.
5. An applicant seeking a Louisiana journeyman plumber examination
generally must have what amount of plumbing experience as an
unindentured apprentice?
A. 3,000 hours
B. 4,000 hours
C. 6,000 hours
D. 8,000 hours
,Rationale: Louisiana rules generally require an applicant for the
journeyman examination to have performed 8,000 hours as an
unindentured apprentice or 7,000 hours as an indentured apprentice under
the required supervision.
6. An applicant for a Louisiana master plumber examination may qualify
through which alternative professional credential, subject to the
applicable experience requirement?
A. Licensed electrician
B. Licensed building inspector
C. Professional engineer with qualifying plumbing experience
D. Certified HVAC technician
Rationale: Louisiana permits certain professional engineers to qualify for
the master plumber examination when they hold the required engineering
credential and have the required plumbing experience.
7. Which plumbing code is specifically identified by the current Louisiana
Plumbing Board examination information as a reference for the
journeyman written examination?
A. 2015 International Plumbing Code
B. 2018 International Plumbing Code
C. 2021 International Plumbing Code
D. 2024 Uniform Plumbing Code
Rationale: The Louisiana Plumbing Board identifies the 2021 International
Plumbing Code as one of the reference materials for its journeyman
written examination.
8. What is the primary purpose of a plumbing trap?
A. To increase water pressure
B. To prevent pipe corrosion
C. To provide a water seal against sewer gases
D. To increase drainage velocity
, Rationale: A properly installed trap retains water in its bend and creates a
seal that prevents sewer gases from entering occupied spaces through the
drainage system.
9. What condition occurs when negative pressure in a drainage system
pulls water out of a fixture trap?
A. Backpressure
B. Back-siphonage
C. Thermal expansion
D. Hydraulic hammer
Rationale: Back-siphonage occurs when negative pressure causes
contaminated or waste-side water to be drawn backward through a
plumbing connection or trap.
10. Which plumbing principle is most directly associated with
preventing sewer gases from entering a building through drainage
piping?
A. Adequate pipe insulation
B. Increased water pressure
C. Properly maintained trap seals and venting
D. Oversized water heaters
Rationale: Trap seals block sewer gases while properly designed venting
protects those seals from pressure conditions that could cause them to
siphon or blow out.
11. What is the principal function of a sanitary drainage system?
A. Supply potable water
B. Provide building heating
C. Convey liquid and solid wastes from plumbing fixtures to an approved
disposal point
D. Increase domestic water pressure
Practice Questions And Correct Answers
(Verified Answers) Plus Rationale 2027
Q&A| Instant Download Pdf.
1. In Louisiana, which state classification most directly covers the
construction, installation, maintenance, or repair of potable and non-
potable water and sewer systems within a building or house?
A. Mechanical Class 6
B. Electrical Class 5
C. Plumbing Class 7
D. Building Construction Class 1
Rationale: Plumbing is classified as Major Classification 7 in Louisiana and
covers potable and non-potable tap water and sewer-water systems within
building structures or houses.
2. Under Louisiana contractor licensing requirements, when does
plumbing work generally require a state contractor license based on
the value of the work?
A. When the value exceeds $1,000
B. When the value exceeds $5,000
C. When the value exceeds $10,000
D. Only when the value exceeds $50,000
,Rationale: Louisiana identifies plumbing as work requiring contractor
licensure when the value of the plumbing work exceeds $10,000.
3. Which organization administers the licensing and regulation of
plumbing professionals in Louisiana?
A. Louisiana State Licensing Board for Contractors only
B. Louisiana Department of Transportation and Development
C. State Plumbing Board of Louisiana
D. Louisiana Department of Revenue
Rationale: The State Plumbing Board of Louisiana regulates plumbers and
administers plumbing licenses and examinations, while contractor
licensing responsibilities can also involve the Louisiana State Licensing
Board for Contractors.
4. Which license generally represents the highest level of individual
plumbing licensure administered by the State Plumbing Board of
Louisiana?
A. Apprentice plumber
B. Tradesman plumber
C. Journeyman plumber
D. Master plumber
Rationale: The master plumber license is the highest principal plumbing
trade license and requires qualifying experience or credentials and
successful examination.
5. An applicant seeking a Louisiana journeyman plumber examination
generally must have what amount of plumbing experience as an
unindentured apprentice?
A. 3,000 hours
B. 4,000 hours
C. 6,000 hours
D. 8,000 hours
,Rationale: Louisiana rules generally require an applicant for the
journeyman examination to have performed 8,000 hours as an
unindentured apprentice or 7,000 hours as an indentured apprentice under
the required supervision.
6. An applicant for a Louisiana master plumber examination may qualify
through which alternative professional credential, subject to the
applicable experience requirement?
A. Licensed electrician
B. Licensed building inspector
C. Professional engineer with qualifying plumbing experience
D. Certified HVAC technician
Rationale: Louisiana permits certain professional engineers to qualify for
the master plumber examination when they hold the required engineering
credential and have the required plumbing experience.
7. Which plumbing code is specifically identified by the current Louisiana
Plumbing Board examination information as a reference for the
journeyman written examination?
A. 2015 International Plumbing Code
B. 2018 International Plumbing Code
C. 2021 International Plumbing Code
D. 2024 Uniform Plumbing Code
Rationale: The Louisiana Plumbing Board identifies the 2021 International
Plumbing Code as one of the reference materials for its journeyman
written examination.
8. What is the primary purpose of a plumbing trap?
A. To increase water pressure
B. To prevent pipe corrosion
C. To provide a water seal against sewer gases
D. To increase drainage velocity
, Rationale: A properly installed trap retains water in its bend and creates a
seal that prevents sewer gases from entering occupied spaces through the
drainage system.
9. What condition occurs when negative pressure in a drainage system
pulls water out of a fixture trap?
A. Backpressure
B. Back-siphonage
C. Thermal expansion
D. Hydraulic hammer
Rationale: Back-siphonage occurs when negative pressure causes
contaminated or waste-side water to be drawn backward through a
plumbing connection or trap.
10. Which plumbing principle is most directly associated with
preventing sewer gases from entering a building through drainage
piping?
A. Adequate pipe insulation
B. Increased water pressure
C. Properly maintained trap seals and venting
D. Oversized water heaters
Rationale: Trap seals block sewer gases while properly designed venting
protects those seals from pressure conditions that could cause them to
siphon or blow out.
11. What is the principal function of a sanitary drainage system?
A. Supply potable water
B. Provide building heating
C. Convey liquid and solid wastes from plumbing fixtures to an approved
disposal point
D. Increase domestic water pressure
