- Overview: What OAR 918-695-0040 Actually Tests
- Domain 1: Drawings, Plans & Bills of Materials
- Domain 2: Math - Areas, Volumes, Slopes, Offsets, Weights
- Domain 3: Tools, Materials & Trade Techniques
- Domain 4: Plumbing Specialty Code, Rules & Hydraulics
- Domain 5: Construction Job Safety
- Domain 6: Disabled Access Provisions
- Exam Format and What "Open-Book" Really Means
- Mapping Domains to a Study Timeline
- Frequently Asked Questions
- OAR 918-695-0040 defines six subject areas - no official percentage weighting is published for any of them.
- The exam is 64 questions, open-book, four hours, with a 75% passing score set by BCD.
- Domain 4 covers the 2023 Oregon Plumbing Specialty Code (based on 2021 UPC), effective October 1, 2023.
- Your authorization letter - not a generic list - controls which references you may bring into the exam room.
Overview: What OAR 918-695-0040 Actually Tests
If you're preparing for the Oregon Journeyman Plumber License Exam (OR-JP), the single most important document you'll never actually read cover-to-cover in a study session is Oregon Administrative Rule 918-695-0040. That rule, enforced by the Building Codes Division (BCD) of the Oregon Department of Consumer and Business Services under the State Plumbing Board, lists the six content areas that make up the journeyman plumber examination. There is no published breakdown of how many of the 64 questions come from each area - BCD does not release a domain weighting - so the smartest approach is to treat every domain as fair game rather than gambling study hours on assumptions about emphasis.
This guide walks through each of the six domains in the order they appear in the rule, explains what "mastery" looks like for a working apprentice, and shows how the domains connect to the exam's open-book format, the 75% passing score, and the 2023 Oregon Plumbing Specialty Code. For a broader look at how difficult candidates generally find the test, see How Hard Is the OR-JP Exam? Complete Difficulty Guide 2026, and if you want the eligibility mechanics before you even schedule a test date, review OR-JP Requirements 2026: Eligibility, Prerequisites & How to Qualify.
Domain 1: Drawings, Plans & Bills of Materials
Understanding of Engineering and Architectural Drawings and Plans
This domain measures whether you can read a set of construction documents well enough to actually build from them - not just recognize symbols. That includes translating a plan view into a materials list and laying out a working plumbing system from the drawing.
- Reading plan, elevation, and isometric drawings for pipe routing
- Preparing an accurate bill of materials from a drawing set
- Laying out fixture groups, vent stacks, and drainage runs from architectural intent
- Interpreting scale, dimensions, and symbol legends consistently
Apprentices who spend time in the field pulling material lists from blueprints have a real advantage here. If your apprenticeship hasn't given you much plan-reading exposure yet, practice with sample residential and light-commercial plan sets before test day rather than trying to learn the skill from a textbook description alone.
Domain 2: Math - Areas, Volumes, Slopes, Offsets, Weights
Computation Skills for Piping Systems
This domain is pure applied math: the kind a journeyman uses daily to size a run, calculate fall on a drain line, or figure out how much a section of pipe will weigh before hoisting it.
- Areas of regular plane figures relevant to job layout
- Volumes of regular solids, including tanks and pipe sections
- Slope and grade calculations for drainage and venting
- Offset and rolling offset calculations using standard fittings
- Clearance requirements around fixtures and piping
- Weight calculations for pipe and fittings by material and size
Because the exam is open-book, you are not expected to memorize formulas from scratch - you're expected to know which formula to apply, plug in the correct values quickly, and use your calculator correctly. A silent, nonprogrammable, nonprinting calculator is permitted, but you should practice offset and slope problems by hand or with that exact type of calculator, since fumbling with an unfamiliar device costs real minutes in a four-hour exam.
Key Takeaway
Practice slope, offset, and weight problems using only the calculator type allowed on exam day - a basic silent, nonprogrammable model - so you're not relearning your tools under time pressure.
Domain 3: Tools, Materials & Trade Techniques
Selection and Use of Tools, Materials and Techniques
This domain covers the practical trade knowledge that separates someone who has completed classroom hours from someone who has actually worked the trade: knowing which tool, material, or joining technique is correct for a given situation.
- Selecting appropriate pipe materials for a given application
- Choosing correct joining methods (solvent weld, soldering, threading, mechanical joints)
- Matching tools to tasks for rough-in and finish work
- Recognizing when a technique is inappropriate for a material or code situation
Candidates who came up through the standard four-year Oregon apprenticeship route tend to find this domain the most familiar, since it mirrors daily jobsite decision-making. Those on the equivalent 576-classroom-hour and combined 3,850-hour commercial/residential path, or the experienced-installer route requiring 7,700 hours each, should double-check that their field exposure actually covered a broad mix of materials and joining methods - not just the systems their specific employer used most.
Domain 4: Plumbing Specialty Code, Rules & Hydraulics
The Plumbing Specialty Code and General Scientific Principles
This is the domain most directly tied to a specific reference book: the currently adopted 2023 Oregon Plumbing Specialty Code, based on the 2021 Uniform Plumbing Code and effective October 1, 2023. It also folds in administrative rules governing plumbers and plumbing work, plus general hydraulics principles.
- Navigating the 2023 Oregon Plumbing Specialty Code structure and index
- Applying administrative rules relating to plumbing and plumbers
- Understanding basic hydraulic principles as they apply to system design
- Cross-referencing code sections quickly during a timed, open-book test
Because the exam is open-book, this domain rewards navigation speed over memorization. You should know your code book's table of contents and index well enough to find a relevant chapter in under a minute - tabbing your code book by chapter before test day is one of the highest-leverage things you can do. For a full breakdown of exactly what "open-book" means in practice, including reference restrictions, see the format section below and OR-JP Study Guide 2026: How to Pass on Your First Attempt.
Domain 5: Construction Job Safety
General Knowledge of Job Safety and Occupational Safety Standards
This domain checks that you understand baseline safety practices and occupational safety standards relevant to construction and plumbing work - the kind of knowledge that protects you and your crew on an active jobsite.
- General occupational safety standards applicable to construction trades
- Jobsite hazard recognition relevant to plumbing installation
- Safe handling practices for tools, materials, and equipment
Safety content tends to feel intuitive to anyone who has worked a real jobsite, but it's still worth a dedicated review pass rather than assuming years of field habit will translate directly into correct answers on a written question. Treat it as a distinct study block, not an afterthought.
Domain 6: Disabled Access Provisions
Disabled Access Provisions Related to Plumbing
The final domain asks for a basic understanding of disabled access provisions found in the Oregon Structural Specialty Code, specifically as they relate to plumbing installations.
- Accessible fixture clearance and mounting height basics
- Accessible route considerations affecting plumbing rough-in
- How structural code access provisions intersect with plumbing fixture placement
This is a narrower domain than the others, but it's easy to under-prepare for because it sits in a different code book than the plumbing-specific material in Domain 4. Don't skip it just because it covers fewer topics - a "basic understanding" standard still means you need to be able to answer direct questions about it.
Exam Format and What "Open-Book" Really Means
All six domains above are tested within a single sitting: 64 questions, four hours, with a 75% passing score required by BCD. The exam is open-book, but that does not mean you can bring whatever materials you like. Your authorization letter - issued after BCD approves your application - controls exactly which references are permitted at your approved test location. Bringing unauthorized materials, or missing ones the letter specifies, can create problems on exam day, so read that letter carefully rather than assuming standard practice applies.
| Exam Feature | Detail |
|---|---|
| Question count | 64 questions |
| Time allowed | 4 hours |
| Passing score | 75% |
| Format | Written, open-book |
| Reference control | Authorization letter specifies approved materials |
| Calculator policy | Silent, nonprogrammable, nonprinting only |
| Authorization window | 60 days to take the exam after approval |
| Retake wait | Minimum 30 days after a failed attempt, with reapplication |
Because you're authorized for a 60-day window once approved, plan your study schedule backward from that window rather than open-ended. A failed attempt requires reapplying and waiting at least 30 days before you can sit again - an incentive to prepare thoroughly across all six domains the first time rather than treating any one area as optional. For the full fee structure behind application and renewal, see OR-JP Certification Cost 2026: Complete Pricing Breakdown, and for exact date logistics see OR-JP Exam Dates 2026: Testing Windows, Deadlines & Scheduling.
Key Takeaway
Because the retake wait is at least 30 days plus a new application, budget enough study time before your first sitting to cover all six domains - not just the ones that feel most familiar from your apprenticeship.
Mapping Domains to a Study Timeline
Rather than studying domains in the order BCD lists them, it often makes sense to sequence your review by how reference-dependent each one is. Code-heavy and math-heavy domains benefit from early, repeated practice because they require building speed with tools (your code book and calculator); trade-knowledge and safety domains benefit from being reviewed closer to test day since they're easier to refresh quickly.
Code Navigation & Math Foundations
- Tab and index your 2023 Oregon Plumbing Specialty Code (Domain 4)
- Drill slope, offset, and weight calculations with your exam-approved calculator (Domain 2)
Plans, Tools & Materials
- Practice bill-of-materials extraction from sample plan sets (Domain 1)
- Review joining methods and material selection scenarios (Domain 3)
Safety & Access
- Review occupational safety standards relevant to plumbing jobsites (Domain 5)
- Study accessible fixture and clearance basics from the structural code (Domain 6)
Full Mixed Review
- Run timed practice sessions mixing all six domains
- Re-check your authorization letter against your final reference materials
For candidates who want structured practice questions organized around these same six domains, working through timed sets on our OR-JP practice test platform can help surface which domain needs another pass before your authorization window closes. If you're still deciding whether the credential is worth the time investment given your career goals, read Is the OR-JP Certification Worth It? Complete ROI Analysis 2026 and OR-JP Salary Guide 2026: Complete Earnings Analysis for context on where a Journeyman Plumber license can take your career, including the range of employers who hire licensed journeymen across residential and commercial work.
Once you've licensed, remember the work doesn't stop at passing: renewal happens every three years on the April 1 cycle, costs $180 including the $30 continuing-education tracking fee, and requires 24 approved CE hours - a good reason to keep a folder of domain notes rather than discarding your study materials after the exam.
Frequently Asked Questions
BCD does not publish an official percentage weighting for any domain in OAR 918-695-0040. Treat all six as equally important rather than assuming one carries more questions than another.
Domain 4 - the Plumbing Specialty Code, administrative rules, and hydraulics - is most directly tied to the 2023 Oregon Plumbing Specialty Code, based on the 2021 UPC and effective October 1, 2023.
No. Your authorization letter controls exactly which references are approved, and only a silent, nonprogrammable, nonprinting calculator is permitted.
You must reapply and wait at least 30 days before retesting, so it's worth reviewing all six domains thoroughly before your first attempt rather than rushing back for a quick retake.
No - the rule specifies a basic understanding of disabled access provisions in the Oregon Structural Specialty Code specifically as they relate to plumbing, not the full structural code.