Start Practice Test

Idaho Plumbing Specialty Appliance Journeyman Exam — Practice Test

What This Practice Exam Covers

The Idaho Plumbing Specialty Appliance Journeyman Exam is a 50-question, 150-minute test with a passing score of 75% (37 correct answers). Questions are drawn from six chapters of the 2017 Idaho State Plumbing Code, with particular emphasis on water heater installation, combustion air, venting, and gas piping — the core of specialty appliance work.

This practice exam offers two options:

Free practice exam: Each attempt gives you 10 questions pulled from a limited pool. You can retake it as many times as you like at no cost — it is a genuine preview of question style, difficulty level, and code-based reasoning, not a demo with dummy content.

Full practice exam (paid): This mirrors the real exam exactly — 50 questions, 150-minute timer, and a pool of 375+ questions so that every attempt generates a fresh, unique set. No two sittings are identical, which means repeated attempts build broad coverage rather than pattern memorization. Questions map directly to the official exam topic outline provided by the test sponsor.

Start with the free exam to get your bearings, then move to the full exam for serious preparation.

What You'll Be Tested On

Chapter 1 — Administration (7 items)

Seven questions cover the legal and procedural framework that governs plumbing work in Idaho. You need to know the scope and purpose of the code, including when a specific requirement overrides a general one (2017 ISPC Section 102.1). Expect questions on what the Authority Having Jurisdiction (AHJ) can require, approve, or revoke — and what liability protections apply. Permit questions are common: which work requires a permit, which is explicitly exempt, and what the application and issuance process looks like. Know the three inspection types — underground, rough-in, and final — and what triggers each. Candidates who treat this chapter as background reading rather than testable content often drop points they cannot afford to lose.

Chapter 2 — Definitions (6 items)

Six questions test terminology, and they are more demanding than they appear. The exam distinguishes closely related terms: a vent stack is not the same as a stack vent; backsiphonage and backpressure are both forms of backflow but arise from different causes; contamination and pollution are defined separately in Sections 205.0 and 218.0 and carry different implications for hazard level. Know the fuel gas venting classifications — Type B, BW, and L vents — and how they differ. The definitions of plumbing appliance, plumbing appurtenance, and plumbing fixture are distinct under Section 203.0 and Section 204.0, and the exam will exploit any confusion between them.

Chapter 3 — General Regulations (7 items)

Seven questions address materials, protection, and installation requirements. You must know what makes a material or method acceptable — listed, labeled, and marked to applicable standards — and how an alternative material gets approved through the AHJ. Pipe protection rules are heavily tested: know the requirements for freezing, corrosion, fire-resistant construction penetrations, and UV exposure. For UV protection of PVC, the code is specific about methods and minimum tape thickness (2017 ISPC Section 312.14). Support intervals by pipe material appear in Tables 313.3 and 313.6, and questions frequently require you to select the correct interval for a named material. Trenching and backfill requirements, including thermoplastic pipe bedding, round out this chapter.

Chapter 5 — Water Heaters (20 items)

This is the single heaviest chapter — 20 questions, 40% of the exam. No other chapter comes close. Allocate your study time accordingly.

Location: Know exactly where water heaters cannot be installed (bedrooms, bathrooms) and what special requirements apply in garages (elevation above floor ignition sources) and attics (per Section 502.1 and related provisions).

Relief devices: Temperature-pressure relief (TPR) valve requirements under Sections 504.1, 504.1.1, 504.3.2, and 504.6 are heavily tested — where the valve must be installed, discharge pipe routing, and prohibited terminations.

Combustion air: The standard indoor method requires 50 cubic feet per 1,000 Btu/h (Section 506.2.1). Know the confined space definition (Section 205.0), the outdoor air methods, and the mechanical ventilation option. Each method has specific opening sizes and placement rules.

Venting: Vent type selection — Type B, BW, L, single-wall metal, or masonry chimney — depends on appliance category. Category I appliances are the focus. Vent sizing for single and multiple appliances requires reading the correct table under Sections 507.2 through 507.5 and 507.13.

Connectors and chimneys: Sections 508.4 through 508.4.3 and Sections 509.5 through 509.10 cover connector clearances, chimney requirements, and multiple-appliance connections in detail.

Chapter 6 — Water Supply and Distribution (5 items)

Five questions address potable water protection, pipe materials, and system sizing. Backflow prevention device selection — air gap, AVB, PVB, SVB, double-check, and reduced-pressure assemblies — requires matching the degree of hazard to the correct device type (Sections 603.4.3, 603.4.9, 603.5.1 through 603.5.15). Lead content requirements for solder and pipe materials are tested under Section 601.3.1 through 601.3.3. Pressure regulator and expansion tank installation falls under Sections 604.2, 604.3, and 604.13. Fixture unit sizing requires correctly reading the appropriate table.

Chapter 12 — Fuel Gas Piping (5 items)

Five questions cover gas piping installation and sizing. Expect at least one sizing question using the longest-length or branch-length method with IFGC Table 402.4(2) for Schedule 40 metallic pipe under natural gas at 0.5 in. w.c. pressure drop. Know acceptable piping materials, underground installation requirements (Sections 1208.1.1, 1208.5.2), pressure testing procedures (Section 1210.1.1), shutoff valve placement, sediment trap requirements, and gas pressure regulator venting rules.

Worked Sample Questions

Question 1 — Chapter 5: Combustion Air

Using the standard method for indoor combustion air, the required volume shall be not less than how many cubic feet per 1,000 Btu/h?

• A. 25 cubic feet
• B. 35 cubic feet
• C. 50 cubic feet ✓
• D. 75 cubic feet

Why C is correct: Section 506.2.1 of the 2017 ISPC establishes the standard method minimum as 50 cubic feet per 1,000 Btu/h. The other figures appear nowhere in this provision. This is a precision recall question — being off by one answer choice costs you the point.

Question 2 — Chapter 1: Code Conflicts

When there is a conflict between a general requirement and a specific requirement, which shall prevail?

• A. The general requirement
• B. The specific requirement ✓
• C. The AHJ decides on a case-by-case basis
• D. The most recently adopted requirement

Why B is correct: Per 2017 ISPC Section 102.1, the specific requirement prevails over the general. This principle applies throughout the code and is a practical rule for resolving conflicts in the field — the code writers anticipated it and codified the answer directly.

Question 3 — Chapter 3: UV Protection of PVC

You are installing PVC drain piping on the exterior of a commercial building where it will be exposed to sunlight. Which of the following is an acceptable method of protection?

• A. Wrap the piping with not less than 0.04 inch thick tape ✓
• B. Install with no protection since PVC is UV-resistant
• C. Apply oil-based exterior paint
• D. Apply a clear UV-resistant lacquer coating

Why A is correct: Section 312.14 of the 2017 ISPC prohibits PVC from direct sunlight exposure. Acceptable exceptions include water-based synthetic latex paint or tape wrapping at a minimum thickness of 0.04 inch (1.02 mm). Oil-based paint is not an approved method, and bare PVC has no UV exemption in this code.

How to Read Your Score

The passing threshold is 75% — 37 out of 50 questions. On a first practice attempt, treat your score as a diagnostic reading, not a verdict. Most candidates score lower than they expect the first time, and that is useful information.

A score below 65% tells you that foundational code knowledge needs reinforcement across multiple chapters before you sit the real exam. A score between 65% and 74% means you are close — targeted work on your weakest topic areas can move you over the line. Scoring at 75–80% on practice should not produce false confidence; real exam questions vary in phrasing and detail, and scoring near the threshold on practice usually means more review is warranted.

Use the topic-by-topic breakdown the full practice exam provides. If Chapter 5 (20 items) is dragging your score, that is where to focus first — it represents nearly half the exam. If Chapter 1 or Chapter 2 are weak, those are fast wins that require memorization rather than calculation. Repeated full-exam attempts with the 375+ question pool will surface different questions each time, giving you progressively broader coverage.

Where Candidates Lose Points

Combustion air volume math: The standard indoor method requires a specific cubic-foot-per-Btu/h ratio. Candidates who confuse the standard method figure with the confined space opening sizes drop points on multiple Chapter 5 questions.

Vent type selection: Choosing between Type B, BW, L, single-wall, and masonry chimney requires knowing both the appliance category and the installation context. Guessing "Type B for everything" fails on chimney liner and connector questions.

TPR valve discharge rules: The code is specific about termination points, pipe material, and prohibited configurations. Candidates read the installation rule but miss the exceptions — or vice versa.

Definition pairs: Chapter 2 questions exploit the distinction between terms like contamination and pollution, or backsiphonage and backpressure. One word in the question stem changes the correct answer.

Gas pipe sizing tables: The IFGC sizing tables require the correct pressure drop column, pipe material, and length row. Using the wrong column — say, 0.3 in. w.c. instead of 0.5 in. w.c. — produces an answer that appears in the options but is wrong.

Time management: Chapter 5 alone is 20 questions. Candidates who work slowly through venting calculations can find themselves short on time for the procedural questions in Chapters 1, 3, and 12 that require only careful reading.

Exam Quick Facts