Idaho Plumbing Contractor Exam Prep

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Official sitting

Questions100
Time4 hours
Passing score75%
BookOpen book

Confirm question count, time, open-book rules, and passing score on the live board bulletin before you sit. We do not guarantee a passing result. Source: PSI Idaho bulletin 12220.

What’s included

18,000+ word study guide

Worked calculations, code-section breakdowns, exam traps, a key-terms glossary and a 30/60/90-day plan.

4 full-length practice exams

Original questions weighted to match the topic mix of the real exam.

400 practice questions

Every one with a written explanation and the code section behind the answer.

Same study guide and four exams on every term. You are choosing how long you can log in.

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What this prep covers

  1. About the Idaho Plumbing Contractor license
  2. How Idaho licensing works
  3. Plumbing math and fundamentals
  4. How the plumbing code is organized
  5. Sanitary drainage, waste, and vent (DWV)
  6. Venting
  7. Water supply and distribution
  8. Fixtures, traps, and interceptors
  9. Water heaters, relief, and gas
  10. Backflow prevention and cross-connection control
  11. Fixtures required by occupancy, clearances, and accessibility
  12. Materials, joining, and storm drainage
  13. Inspection, testing, and isometrics
  14. Worked calculations
  15. Sample exam questions, solved
  16. Common mistakes and exam traps

…and 4 further sections in the full guide.

Idaho Plumbing Contractor licensing, explained

About the Idaho Plumbing Contractor license

Idaho licenses plumbers through the Idaho Division of Occupational and Professional Licenses (DOPL) and its State Plumbing Board. Idaho does not have a "Master Plumber" tier — this course prepares you for the Plumbing Contractor license, the credential that qualifies a business to contract directly with the public for plumbing work. Under Idaho Code §54-2611, a plumbing contractor must either personally hold a Plumbing Journeyman license or keep a qualified journeyman employed on all of its work. Most candidates for the Contractor exam already hold a Plumbing Journeyman license, which requires 8,000 hours of documented work experience plus four years of approved schooling, or 16,000 hours of experience without formal schooling, and passing the journeyman exam before DOPL will issue that license. A licensed plumbing contractor may pull permits, contract for and supervise plumbing installations, and employ journeymen and apprentices.

Your exam is built on the Uniform Plumbing Code (UPC) as adopted by Idaho — currently the Idaho State Plumbing Code (2017 ISPC), based on the 2015 UPC (confirm the exact edition on the current bulletin — the exam is written to the adopted edition, not necessarily the newest). The two model codes — the Uniform Plumbing Code (UPC) published by IAPMO and the International Plumbing Code (IPC) published by the ICC — agree on the physics but differ in tables, fixture-unit values, and some sizing methods, so always work from the one your state adopted.

Know these scope facts cold: the license is held by the individual; most work requires a permit and inspection (rough-in/top-out and final); you must work within the classification you hold; and unlicensed or out-of-scope plumbing work is a violation that can cost you the license and carry penalties. Plumbing protects public health — the exam constantly returns to the two core purposes of the code: deliver safe potable water and remove waste without contaminating that water.

How Idaho licensing works

  • Journeyman prerequisite: 8,000 hours of documented work experience plus 4 years of approved schooling, or 16,000 hours of experience without formal schooling; you must pass the journeyman exam before DOPL issues that license.
  • Plumbing Contractor: you personally hold a journeyman license, or your business keeps a qualified journeyman employed on all work, before DOPL will issue the contractor license (Idaho Code §54-2611).
  • Application: submit the application and fee to DOPL and receive an approval letter before you may schedule the exam.
  • Exam format: the Plumbing Contractor exam is open book, computer-based, 4 hours, and delivered by PSI under bulletin 12220. It is not a walk-in exam at a DOPL office. Bulletin 12220 totals 100 items: 32 from the 2017 Idaho State Plumbing Code chapters on the outline, 8 from schematic sizing, and 60 points from the DOPL Contractor's Business and Law Reference Manual, which is also an approved open-book reference. The Specialty (Appliance/Water Pump) Contractor exam is 100% business-and-law. The Journeyman exam is separate, administered by PSI, and covers the plumbing code only (no business/law). Passing score is 75 percent for the Contractor and Specialty Contractor exams (70 percent for the PSI Journeyman exam) — confirm current details on the DOPL candidate bulletin.
  • Renewal: licenses renew on a periodic cycle through DOPL. Idaho currently has no continuing-education requirement for plumbing licenses — verify your specific renewal date and fee on the DOPL licensee portal rather than assuming a CE obligation.

This is the opening of the full study guide. The complete guide continues into code navigation, worked calculations and solved exam questions.

Other Idaho exam prep

Idaho Plumbing Contractor exam — common questions

Who administers the Idaho Plumbing Contractor exam?

The Idaho Plumbing Contractor examination is administered by Idaho DOPL Plumbing Board / PSI. Plumbing Contractor page of bulletin 12220 effective 7/9/2026: 100 questions, 75 percent, 240 minutes, open book. Bring the printed business-and-law manual in a three-ring binder, plus the 2015 UPC or the 2017 Idaho State Plumbing Code. No calculator. Outline: ISPC ch2=1, ch5=5, ch6=5, ch7=2, ch8=5, ch9=5, ch10=3, ch11=2, ch12=4 (32), schematic sizing 8, manual sections 1-13 weights 1,1,1,1,1,20,15,3,1,2,10,1,3 (60). Not journeyman (100/70/180, code only). Not specialty contractor (100/75/240, manual only). Fee $75. IDAPA 24.39.20: contractor must hold the journeyman certificate and post a $2,000 compliance bond..

How many questions are on the Idaho Plumbing Contractor exam?

The exam contains 100 questions. You need 75% to pass. You are allowed 4 hours.

How much practice does this prep include?

It includes 4 full-length practice exams and 400 practice questions in total. Every question has a written explanation naming the code section the answer comes from.

How long is the study guide?

The Idaho Plumbing Contractor guide runs to roughly 18,629 words, covering 20 sections from licensing rules through worked calculations and solved exam questions.

How long do I get access?

Choose 30, 60 or 90 days at checkout. Access begins the moment you enrol, works on any device, and you can retake every practice exam as often as you like. Days remaining are shown in your dashboard and you can extend at any time.

Is this an official Idaho Plumbing Contractor exam?

No. This is independent preparation material. It is not affiliated with or endorsed by any state licensing board or exam vendor, and it does not contain real exam questions. Always confirm current requirements with your licensing board.

About this Idaho Plumbing Contractor prep

This prep is built specifically for the Idaho Plumbing Contractor examination and includes a 18,000+-word study guide written for this exam, 4 full-length practice exams and 400 practice questions, each with a written explanation.

The Idaho Plumbing Contractor examination is administered by Idaho DOPL Plumbing Board / PSI. Plumbing Contractor page of bulletin 12220 effective 7/9/2026: 100 questions, 75 percent, 240 minutes, open book. Bring the printed business-and-law manual in a three-ring binder, plus the 2015 UPC or the 2017 Idaho State Plumbing Code. No calculator. Outline: ISPC ch2=1, ch5=5, ch6=5, ch7=2, ch8=5, ch9=5, ch10=3, ch11=2, ch12=4 (32), schematic sizing 8, manual sections 1-13 weights 1,1,1,1,1,20,15,3,1,2,10,1,3 (60). Not journeyman (100/70/180, code only). Not specialty contractor (100/75/240, manual only). Fee $75. IDAPA 24.39.20: contractor must hold the journeyman certificate and post a $2,000 compliance bond.. This prep is written to that board’s current scope, not to a generic national syllabus.

The real Idaho Plumbing Contractor exam contains 100 questions, with a passing score of 75%. Our practice exams mirror that structure so the format is familiar before you sit it.

Topics covered

  • About the Idaho Plumbing Contractor license
  • How Idaho licensing works
  • Plumbing math and fundamentals
  • How the plumbing code is organized
  • Sanitary drainage, waste, and vent (DWV)
  • Venting
  • Water supply and distribution
  • Fixtures, traps, and interceptors
  • Water heaters, relief, and gas
  • Backflow prevention and cross-connection control
  • Fixtures required by occupancy, clearances, and accessibility
  • Materials, joining, and storm drainage
  • Inspection, testing, and isometrics
  • Worked calculations
  • Sample exam questions, solved
  • Common mistakes and exam traps
  • Key chapters and tables to tab
  • Glossary of must-know terms
  • Your 30 / 60 / 90 day study plan
  • Exam-day strategy

How access works

You are paying for access length (30, 60, or 90 days). The study guide and four timed exams are the same on every term. Access starts when you enrol and works on any device for that term.

Not affiliated with or endorsed by any state licensing board or exam vendor. For exam-preparation purposes only.