IDAHO PLUMBING CODE EXAM
QUESTIONS AND CORRECT ANSWERS
(VERIFIED ANSWERS) PLUS
RATIONALES 2026 Q&A | INSTANT
DOWNLOAD PDF.
Core Domains
• Uniform Plumbing Code (UPC) Adoption & Idaho Amendments
• Sanitary Drainage Systems – Sizing, Slope, & Materials
• Water Supply & Distribution – Sizing, Pressure, & Protection
• Venting Systems – Trap Seals, Vent Sizing, & Code Requirements
• Plumbing Fixtures – Installation Requirements & DFU Values
• Backflow Prevention & Cross-Connection Control
• Gas Piping & Water Heater Installation
• Licensing, Permits, & Authority Having Jurisdiction (AHJ)
• Idaho Statutes & Administrative Rules (IDAPA)
• Blueprint Reading & System Design Calculations
Introduction
This comprehensive examination is designed to assess the candidate's
knowledge of the Idaho Plumbing Code as adopted by the Idaho Division
of Building Safety. The exam covers the Uniform Plumbing Code (UPC)
with state-specific amendments, including drainage, water supply,
venting, fixtures, backflow prevention, gas piping, and licensing
requirements. Questions are structured to evaluate both foundational code
knowledge and the ability to apply regulations to real-world plumbing
scenarios. Each question includes a detailed rationale to reinforce learning
,and ensure exam readiness. This resource is ideal for journeyman
plumbers, contractors, and apprentices preparing for Idaho state licensing
examinations.
Questions 1 – 100
1. Which of the following best describes the primary purpose of the
Idaho Plumbing Code?
A. To increase construction costs
B. To safeguard public health and safety
C. To standardize architectural design
D. To limit the number of plumbing fixtures
B. To safeguard public health and safety
RATIONALE: The code's chief objective is to protect public health
and safety by establishing minimum standards for plumbing systems.
2. Who is the Authority Having Jurisdiction (AHJ) for most plumbing
work in Idaho?
A. The local fire department
B. The Idaho State Department of Health and Welfare
C. The city or county building official
D. The National Plumbing Association
C. The city or county building official
RATIONALE: The AHJ is typically the municipal or county building
official who enforces the plumbing code.
3. Under Idaho law, which of the following work does NOT require a
plumbing permit?
A. Installing a new water heater
B. Replacing a faucet in a single-family residence
,C. Adding a new bathroom drain line
D. Connecting a new sewer line to the public sewer
B. Replacing a faucet in a single-family residence
RATIONALE: Homeowner repairs such as faucet replacement on a
single-family home are exempt from permitting.
4. Which Idaho statute defines the minimum licensing
requirements for a Journeyman plumber?
A. Idaho Code § 54-1222
B. Idaho Code § 54-1223
C. Idaho Code § 54-1224
D. Idaho Code § 54-1225
B. Idaho Code § 54-1223
RATIONALE: Idaho Code § 54-1223 specifically outlines the
qualifications, experience, and examination requirements for a
Journeyman plumber license.
5. In the Idaho State Plumbing Code, the term "fixture unit" is
defined as:
A. The volume of water a fixture uses per minute
B. A numerical value representing the probable demand on a plumbing
system
C. The pressure rating of a pipe
D. The size of a drain pipe required for a fixture
B. A numerical value representing the probable demand on a
plumbing system
RATIONALE: A fixture unit is a dimensionless number used to
estimate the load a fixture places on a drainage or water supply system.
6. Which Idaho plumbing code section defines the term "fixture
unit"?
, A. Chapter 2 – Definitions
B. Chapter 4 – Fixtures
C. Chapter 6 – Water Supply
D. Chapter 7 – Drainage
A. Chapter 2 – Definitions
RATIONALE: Chapter 2 of the Idaho Plumbing Code contains all
definitions, including "fixture unit," which quantifies the load a plumbing
fixture places on a system.
7. The Idaho State Plumbing Board consists of how many voting
members?
A. 3
B. 5
C. 7
D. 9
C. 7
RATIONALE: Idaho law mandates a seven-member board, including
the state health officer and representatives from the plumbing industry.
8. Which agency issues permits for new plumbing installations in
Idaho?
A. Idaho Department of Health and Welfare
B. Division of Building Safety
C. Idaho Water Resources Board
D. Idaho Department of Environmental Quality
B. Division of Building Safety
RATIONALE: The Division of Building Safety is responsible for
reviewing and issuing plumbing permits.
9. A plumber who performs work without a valid license in Idaho
may be subject to:
QUESTIONS AND CORRECT ANSWERS
(VERIFIED ANSWERS) PLUS
RATIONALES 2026 Q&A | INSTANT
DOWNLOAD PDF.
Core Domains
• Uniform Plumbing Code (UPC) Adoption & Idaho Amendments
• Sanitary Drainage Systems – Sizing, Slope, & Materials
• Water Supply & Distribution – Sizing, Pressure, & Protection
• Venting Systems – Trap Seals, Vent Sizing, & Code Requirements
• Plumbing Fixtures – Installation Requirements & DFU Values
• Backflow Prevention & Cross-Connection Control
• Gas Piping & Water Heater Installation
• Licensing, Permits, & Authority Having Jurisdiction (AHJ)
• Idaho Statutes & Administrative Rules (IDAPA)
• Blueprint Reading & System Design Calculations
Introduction
This comprehensive examination is designed to assess the candidate's
knowledge of the Idaho Plumbing Code as adopted by the Idaho Division
of Building Safety. The exam covers the Uniform Plumbing Code (UPC)
with state-specific amendments, including drainage, water supply,
venting, fixtures, backflow prevention, gas piping, and licensing
requirements. Questions are structured to evaluate both foundational code
knowledge and the ability to apply regulations to real-world plumbing
scenarios. Each question includes a detailed rationale to reinforce learning
,and ensure exam readiness. This resource is ideal for journeyman
plumbers, contractors, and apprentices preparing for Idaho state licensing
examinations.
Questions 1 – 100
1. Which of the following best describes the primary purpose of the
Idaho Plumbing Code?
A. To increase construction costs
B. To safeguard public health and safety
C. To standardize architectural design
D. To limit the number of plumbing fixtures
B. To safeguard public health and safety
RATIONALE: The code's chief objective is to protect public health
and safety by establishing minimum standards for plumbing systems.
2. Who is the Authority Having Jurisdiction (AHJ) for most plumbing
work in Idaho?
A. The local fire department
B. The Idaho State Department of Health and Welfare
C. The city or county building official
D. The National Plumbing Association
C. The city or county building official
RATIONALE: The AHJ is typically the municipal or county building
official who enforces the plumbing code.
3. Under Idaho law, which of the following work does NOT require a
plumbing permit?
A. Installing a new water heater
B. Replacing a faucet in a single-family residence
,C. Adding a new bathroom drain line
D. Connecting a new sewer line to the public sewer
B. Replacing a faucet in a single-family residence
RATIONALE: Homeowner repairs such as faucet replacement on a
single-family home are exempt from permitting.
4. Which Idaho statute defines the minimum licensing
requirements for a Journeyman plumber?
A. Idaho Code § 54-1222
B. Idaho Code § 54-1223
C. Idaho Code § 54-1224
D. Idaho Code § 54-1225
B. Idaho Code § 54-1223
RATIONALE: Idaho Code § 54-1223 specifically outlines the
qualifications, experience, and examination requirements for a
Journeyman plumber license.
5. In the Idaho State Plumbing Code, the term "fixture unit" is
defined as:
A. The volume of water a fixture uses per minute
B. A numerical value representing the probable demand on a plumbing
system
C. The pressure rating of a pipe
D. The size of a drain pipe required for a fixture
B. A numerical value representing the probable demand on a
plumbing system
RATIONALE: A fixture unit is a dimensionless number used to
estimate the load a fixture places on a drainage or water supply system.
6. Which Idaho plumbing code section defines the term "fixture
unit"?
, A. Chapter 2 – Definitions
B. Chapter 4 – Fixtures
C. Chapter 6 – Water Supply
D. Chapter 7 – Drainage
A. Chapter 2 – Definitions
RATIONALE: Chapter 2 of the Idaho Plumbing Code contains all
definitions, including "fixture unit," which quantifies the load a plumbing
fixture places on a system.
7. The Idaho State Plumbing Board consists of how many voting
members?
A. 3
B. 5
C. 7
D. 9
C. 7
RATIONALE: Idaho law mandates a seven-member board, including
the state health officer and representatives from the plumbing industry.
8. Which agency issues permits for new plumbing installations in
Idaho?
A. Idaho Department of Health and Welfare
B. Division of Building Safety
C. Idaho Water Resources Board
D. Idaho Department of Environmental Quality
B. Division of Building Safety
RATIONALE: The Division of Building Safety is responsible for
reviewing and issuing plumbing permits.
9. A plumber who performs work without a valid license in Idaho
may be subject to:
