Idaho Plumbing Journeyman Exam

Idaho Plumbing Journeyman Exam: What You Need to Know to Pass in 2026

Passing the Idaho Plumbing Journeyman exam means you can work independently, pull permits under your own name, and command a higher wage. It's a real milestone. The exam has 100 questions, runs 3 hours, and covers the 2015 Uniform Plumbing Code plus Idaho-specific amendments. Open book — but don't let that fool you. If you don't know your way around these codes cold, the clock will eat you alive. This guide breaks down every topic area, shows you real sample questions, and tells you exactly what to study and in what order.

Start with our free practice exam to see where you stand right now.

Idaho Plumbing Journeyman Exam Overview

Here are the basics:

• Questions: 100 scored questions
• Time limit: 180 minutes (3 hours)
• Passing score: 70 correct (70%)
• Format: Open book — you bring the books
• Administered by: PSI Exams

The Idaho Plumbing Journeyman exam is open book, which means you can bring the 2015 Uniform Plumbing Code (UPC) and the 2017 Idaho State Plumbing Code (2017 ISPC). You are responsible for bringing your own copies. Pre-exam highlighting, underlining, and permanent tabs are allowed — but no writing during the exam, and no sticky notes. Those will be confiscated.

The exam is administered by PSI. You can register online through the exam registration page (available 24/7) or by calling PSI at 855-340-3713. The fee is $75.00 per attempt, non-refundable.

Topics Covered on the Idaho Plumbing Exam

The exam pulls from 11 topic areas. Here's how many questions come from each — this is where you should focus your time.

The Idaho state amendments alone make up 25 of your 100 questions — that's your single biggest topic. Spend serious time there. Gas piping (Chapter 12) is next at 12 questions, followed by storm drainage, drainage systems, and venting at 9–10 questions each.

Sample Journeyman Exam Questions

Here are five real-style questions from the Idaho plumbing journeyman exam practice pool. Work through them — then check the free practice exam to see how you actually score. Answers are not given here intentionally.

Question 1 (UPC Chapter 6 – Water Supply / Medium)
According to the 2017 ISPC, what type of backflow prevention is required for an irrigation system that includes a chemical injector?
- A) Atmospheric vacuum breaker (AVB)
- B) Pressure vacuum breaker backflow prevention assembly (PVB)
- C) Double check valve backflow prevention assembly (DC)
- D) Reduced-pressure principle backflow prevention assembly (RP)

Question 2 (UPC Chapter 10 – Traps & Interceptors / Medium)
What minimum water seal depth is required for sand interceptors under the 2017 Idaho State Plumbing Code?
- A) 6 inches
- B) 8 inches
- C) 2 inches
- D) 4 inches

Question 3 (UPC Chapter 3 – General Regulations / Easy)
Schedule 40 PVC and ABS DWV piping with solvent cemented joints shall be horizontally supported at intervals not exceeding ______ feet for all sizes.
- A) 3
- B) 4
- C) 6
- D) 10

Question 4 (UPC Chapter 12 – Gas Piping / Easy)
What is the minimum cover requirement for underground gas piping systems according to the 2017 ISPC?
- A) 6 inches
- B) 12 inches
- C) 18 inches
- D) 24 inches

Question 5 (UPC Chapter 11 – Storm Drainage / Hard)
For controlled-flow roof drainage systems, not less than two drains shall be installed in roof areas of 10,000 square feet or less, and not less than one additional drain for each additional 10,000 square feet.
- True
- False

Know the answers? Take our free practice exam and find out.

What Types of Questions to Expect

Our full practice pool has 946 questions across all 11 topic areas. Here's what each section actually tests:

UPC Chapter 3 (86 practice questions): Pipe material standards, support intervals by material type, nail plate and sleeve requirements, and trenching/backfill rules for thermoplastic pipe.

UPC Chapter 4 (93 practice questions): Fixture clearances, minimum fixture counts by occupancy from Table 422.1, flow rate limits for water closets and lavatories, and shower compartment waterproofing requirements.

UPC Chapter 5 (78 practice questions): Water heater placement rules, T&P relief valve requirements, combustion air sizing, and vent type selection for Category I appliances.

UPC Chapter 6 (91 practice questions): Backflow preventer types and when each applies, cross-connection control, pipe material standards including lead content rules, and joining methods for copper, PEX, CPVC, and PE.

UPC Chapter 7 (83 practice questions): Drainage fixture unit values, pipe sizing, slope requirements for horizontal drains and building sewers, cleanout spacing and access, and joint types by material.

UPC Chapter 8 (85 practice questions): Air gap vs. air break for indirect waste, indirect waste receptor installation, condensate piping sizing, and chemical waste pretreatment requirements.

UPC Chapter 9 (88 practice questions): Vent pipe sizing from fixture units and developed length, vent termination clearances, wet venting for bathroom groups, and circuit vent requirements.

UPC Chapter 10 (88 practice questions): Trap arm lengths, Table 1002.2 distances, prohibited trap types, trap seal depth, and grease interceptor sizing — both hydromechanical and gravity methods.

UPC Chapter 11 (90 practice questions): Storm drain sizing using Tables 1101.8 and 1101.12, roof drain and conductor sizing, primary vs. secondary drainage requirements, and subsoil drain installation.

UPC Chapter 12 (76 practice questions): Gas piping system design and sizing, approved materials and joining methods, underground installation requirements, pressure testing procedures, and inspection certificates.

2017 Idaho State Plumbing Code (88 practice questions): Idaho-specific amendments including testing in the presence of the AHJ, the Idaho definition of a plumbing system, fixture and water heater amendments, backflow changes, and the 18-inch ignition-source height rule in garages.

Study Materials for the Idaho Plumbing License Exam

This is an open-book exam, so your books are tools — treat them like tools.

Required:
- 2017 Idaho State Plumbing Code (2017 ISPC) — 25 questions come straight from this. You need the actual code, not a summary.

You'll also need the 2015 Uniform Plumbing Code (UPC). Check whether your employer has a copy, or pick one up — you cannot borrow it from the test center.

Highly recommended:

• Sharpie Tank Highlighters — Get a set with multiple colors. Color-code by chapter: one color for Chapter 7, another for Chapter 9, and so on. Fluorescent ink that resists smearing, wide barrel for durability. A 12-pack in assorted colors gives you enough to build a real system.

• Redi-Tag Permanent White Tabs — These are the key to open-book speed. Tab every major table and section you'll need under pressure. They're laser-printable, so you can label them cleanly. 375 tabs per pack — more than enough to index both books thoroughly. Tabs that fall off mid-exam are useless; these stay put.

Pre-index your books before exam day. On the real exam, you don't have time to flip around hunting for Table 1101.8. You need to go straight there.

Study Tips for the Idaho Plumbing Journeyman Exam

Give yourself three to six weeks. Use the official exam bulletin as your roadmap. It tells you exactly what's tested.

Build speed, not just knowledge. Open book doesn't mean unlimited time. Practice finding answers fast — flipping to the right table or section in under 30 seconds. That's the real skill.

Set your practice bar at 80%. You need 70 to pass. If you're hitting 80% consistently on practice tests, you have a real margin on test day. Aim higher in practice.

Work the exam in two passes. Answer everything you know immediately. Flag anything uncertain and skip it. Come back to flagged questions on the second pass. Don't burn five minutes on one question when you haven't touched 20 others.

Prioritize by weight. Idaho amendments (25 questions), gas piping (12), storm drainage and venting (9 each) — that's more than half the exam. These get the most study time.

Manage the pressure. A little anxiety is normal. If you feel stuck on a question, take a few slow breaths and reset before you keep reading. If the test center allows a short break, use it — but remember the clock keeps running.

FAQs: Idaho Plumbing Journeyman Exam

How much does the Idaho Plumbing Journeyman exam cost?
The exam fee is $75.00. Fees are non-refundable and non-transferable. Your fee is valid for one year from the date of payment.

How many questions are on the Idaho Plumbing Journeyman exam and how long do I have?
The exam has 100 scored questions. You have 180 minutes (3 hours) to complete it.

What is the passing score?
You need 70 correct answers out of 100 to pass.

How do I register?
Register through the exam registration page, which is available 24/7, or call PSI at 855-340-3713 during their hours of operation.

Is the exam open book?
Yes. You can bring the 2015 UPC and the 2017 Idaho State Plumbing Code. You bring your own copies — the test center does not provide them.

Can I write in my books during the exam?
No. Highlighting, underlining, and permanent indexing before the exam are fine. But no writing during the exam session. Post-its and temporary markers are prohibited and will be confiscated.

What ID do I need?
One form of current, government-issued photo ID with your name, signature, and photo. A driver's license, state ID, U.S. passport, military ID, or alien registration card all work. Temporary IDs are not accepted unless accompanied by the original expired ID.

What happens if I fail?
You can retake the exam as many times as needed. Each attempt requires a new $75.00 fee.

How do I cancel or reschedule?
Cancel at least 2 days before your scheduled date to avoid losing your fee. Call PSI at 855-340-3713 or cancel through the PSI website. Voicemail and email are not accepted as cancellation methods.

Where can I take the exam?
At PSI test centers in Idaho (Boise, Lewiston, Moscow, Twin Falls, Idaho Falls), Washington, Oregon, Wyoming, Nevada, and other PSI locations nationwide.

How much do journeyman plumbers make in Idaho?
Journeyman plumbers in Idaho typically earn between $55,000 and $75,000 per year depending on location, employer, and experience. Boise and the Treasure Valley generally pay on the higher end of that range. Your license is what gets you there — and what keeps you moving up.

Ready to Test Your Knowledge?

You know the topics. You know what's weighted. Now put it to work.

Start with our free practice exam — 10 questions, no account required, no cost. Get a feel for the format and question style. When you're ready to train seriously, the full practice exam matches the real test: 100 questions, 180-minute timer, full topic breakdown, and a score report that shows exactly where you need work. Every attempt draws from a large question pool, so you won't see the same exam twice.

Visit the state licensing website for application requirements and the official exam bulletin for registration details. Get your books tabbed. Get your highlighters ready. Then get after it.