NCCER PLUMBING LEVEL 3 CERTIFICATION EXAM – ACTUAL EXAM PRACTICE
QUESTIONS AND 100% VERIFIED CORRECT ANSWERS | COMPLETE EXAM PREP
TESTBANK | GUARANTEED PASS | INSTANT DOWNLOAD PDF
Core Domains
Applied Math and Sizing
Sizing and Protecting the Water Supply System
Potable Water Supply Treatment
Types of Venting
Sizing DWV and Storm Systems
Sewage Pumps and Sump Pumps
Corrosive-Resistant Waste Piping
Compressed Air
Service Plumbing
Introduction
The NCCER Plumbing Level 3 Certification Exam is a comprehensive assessment
designed to evaluate a technician's mastery of advanced plumbing systems and theoretical
,principles. This exam assesses knowledge in areas such as sizing complex water supply
systems, specialized venting techniques, and the installation of pumps and high-pressure
air lines. Utilizing a multiple-choice and scenario-based format, the test focuses on
practical application, regulatory compliance, and professional decision-making in the field.
Candidates must demonstrate a high level of technical proficiency and problem-solving
skills to ensure the safety and efficiency of commercial and industrial plumbing
infrastructure.
SECTION ONE: QUESTIONS 1-100
1. When sizing a water supply system, what is the minimum pressure required at the
fixture furthest from the source?
A. 4 psi
B. 5 psi
🔴 C. 8 psi
D. 12 psi
🔵 Explanation: Standard plumbing codes typically require a minimum residual
pressure of 8 psi at the most remote fixture to ensure proper function.
2. Which device is used to prevent backflow in a high-hazard situation where back-
pressure is present?
A. Atmospheric vacuum breaker
, 🔴 B. Reduced pressure principle backflow preventer
C. Pressure vacuum breaker
D. Double check valve assembly
🔵 Explanation: The RPZ (Reduced Pressure Zone) assembly is the only mechanical
backflow preventer designed for high-hazard back-pressure applications.
3. What is the maximum distance a 2-inch vent can be placed from a trap?
A. 4 feet
B. 6 feet
🔴 C. 8 feet
D. 10 feet
🔵 Explanation: According to standard plumbing codes, the maximum horizontal
distance from a 2-inch trap to its vent is 8 feet.
4. A sewage ejector pump must be capable of handling solids with a minimum diameter
of:
A. 1 inch
B. 1.5 inches
🔴 C. 2 inches
D. 3 inches
🔵 Explanation: To prevent clogging in residential and commercial applications,
sewage pumps must be able to pass 2-inch solids.
, 5. When installing a glass piping system for corrosive waste, which joining method is
most common?
A. Solvent welding
B. Brazing
🔴 C. Compression couplings with TFE liners
D. Threaded joints
🔵 Explanation: Borosilicate glass pipe is joined using specialized compression
couplings with chemical-resistant liners to ensure leak-proof, corrosive-resistant
seals.
6. What is the primary purpose of a circuit vent?
🔴 A. To provide air circulation for a battery of fixtures
B. To vent a single water closet
C. To prevent suds pressure in high-rise buildings
D. To act as a relief vent for a stack
🔵 Explanation: A circuit vent provides airflow for a horizontal branch that connects
two or more trap-arm openings (a battery) to the drainage system.
7. In a compressed air system, why are pipes pitched back toward the receiver?
A. To increase air velocity
B. To reduce friction loss
🔴 C. To allow moisture to drain back to the moisture trap
QUESTIONS AND 100% VERIFIED CORRECT ANSWERS | COMPLETE EXAM PREP
TESTBANK | GUARANTEED PASS | INSTANT DOWNLOAD PDF
Core Domains
Applied Math and Sizing
Sizing and Protecting the Water Supply System
Potable Water Supply Treatment
Types of Venting
Sizing DWV and Storm Systems
Sewage Pumps and Sump Pumps
Corrosive-Resistant Waste Piping
Compressed Air
Service Plumbing
Introduction
The NCCER Plumbing Level 3 Certification Exam is a comprehensive assessment
designed to evaluate a technician's mastery of advanced plumbing systems and theoretical
,principles. This exam assesses knowledge in areas such as sizing complex water supply
systems, specialized venting techniques, and the installation of pumps and high-pressure
air lines. Utilizing a multiple-choice and scenario-based format, the test focuses on
practical application, regulatory compliance, and professional decision-making in the field.
Candidates must demonstrate a high level of technical proficiency and problem-solving
skills to ensure the safety and efficiency of commercial and industrial plumbing
infrastructure.
SECTION ONE: QUESTIONS 1-100
1. When sizing a water supply system, what is the minimum pressure required at the
fixture furthest from the source?
A. 4 psi
B. 5 psi
🔴 C. 8 psi
D. 12 psi
🔵 Explanation: Standard plumbing codes typically require a minimum residual
pressure of 8 psi at the most remote fixture to ensure proper function.
2. Which device is used to prevent backflow in a high-hazard situation where back-
pressure is present?
A. Atmospheric vacuum breaker
, 🔴 B. Reduced pressure principle backflow preventer
C. Pressure vacuum breaker
D. Double check valve assembly
🔵 Explanation: The RPZ (Reduced Pressure Zone) assembly is the only mechanical
backflow preventer designed for high-hazard back-pressure applications.
3. What is the maximum distance a 2-inch vent can be placed from a trap?
A. 4 feet
B. 6 feet
🔴 C. 8 feet
D. 10 feet
🔵 Explanation: According to standard plumbing codes, the maximum horizontal
distance from a 2-inch trap to its vent is 8 feet.
4. A sewage ejector pump must be capable of handling solids with a minimum diameter
of:
A. 1 inch
B. 1.5 inches
🔴 C. 2 inches
D. 3 inches
🔵 Explanation: To prevent clogging in residential and commercial applications,
sewage pumps must be able to pass 2-inch solids.
, 5. When installing a glass piping system for corrosive waste, which joining method is
most common?
A. Solvent welding
B. Brazing
🔴 C. Compression couplings with TFE liners
D. Threaded joints
🔵 Explanation: Borosilicate glass pipe is joined using specialized compression
couplings with chemical-resistant liners to ensure leak-proof, corrosive-resistant
seals.
6. What is the primary purpose of a circuit vent?
🔴 A. To provide air circulation for a battery of fixtures
B. To vent a single water closet
C. To prevent suds pressure in high-rise buildings
D. To act as a relief vent for a stack
🔵 Explanation: A circuit vent provides airflow for a horizontal branch that connects
two or more trap-arm openings (a battery) to the drainage system.
7. In a compressed air system, why are pipes pitched back toward the receiver?
A. To increase air velocity
B. To reduce friction loss
🔴 C. To allow moisture to drain back to the moisture trap
