Plumbing Exam Questions by Topic
214 original plumbing license exam questions across fourteen topics. Every question carries a full explanation, the code family and edition behind it, and an honest note where the provision varies by jurisdiction.
- Total questions
- 214
- Multiple choice
- 182
- Calculations
- 20
- Diagrams
- 12
How the question bank is organised
The fourteen topics are not arbitrary. They follow the subject areas that appear in publicly posted examination content outlines: the documents licensing boards and their vendors publish to tell candidates what will be examined. Those outlines name subject areas and their approximate weightings; they do not supply questions, and none are reproduced here.
Three exercise types appear across the topics. Multiple-choice questions test code application and recall, with distractors chosen to catch the specific half-knowledge that loses marks: the 1/4 inch per foot slope applied to 4 inch pipe, the 0.25 percent lead limit quoted where 0.2 percent belongs. Calculation exercises take a numerical answer, check it against a stated tolerance, validate the unit you expressed it in, and then show the worked solution step by step. Diagram exercises put a schematic in front of you and ask you to identify a component, a measurement span or an installation fault, highlighting the correct answer on the drawing once you commit.
Every answer states where its technical content comes from: a code family and edition, a published standard, or a derivation from physics or arithmetic that you can check yourself. Where a provision differs between the IPC and the UPC, or between editions, the question says so rather than pretending there is a single national answer: because there is not. There is no national plumbing code in the United States, and which code applies to you depends on your state.
All fourteen topics
Plumbing Fundamentals
Terminology, materials, joining methods and the vocabulary every other exam section is written in.
16 questionsWater Supply Systems
Service and distribution sizing, pressure control, backflow prevention and hot water delivery.
16 questionsDrainage, Waste & Vent (DWV)
Fixture unit loading, slope, stack and branch sizing, cleanouts and offsets.
18 questionsPipe Sizing & Materials
Diameter selection from flow and velocity, material properties, approved uses and support spacing.
16 questionsWater Pressure & Flow
Static and dynamic pressure, friction loss, pump head and transient pressure.
16 questionsPlumbing Fixtures
Flow and flush rates, clearances, mounting heights, flood level rims and minimum fixture counts.
14 questionsTraps & Interceptors
Trap seal depth, prohibited trap types, trap arm limits and interceptor selection.
14 questionsVenting Requirements
Vent types and selection, terminal location, sizing, wet and circuit venting, AAVs.
16 questionsPlumbing Safety
Trenching and excavation, confined spaces, hot work, PPE and material safety law.
14 questionsInternational Plumbing Code (IPC)
How the International Plumbing Code is organised, what its tables govern and where it departs from the UPC.
16 questionsUniform Plumbing Code (UPC)
How the Uniform Plumbing Code is organised, its sizing approach and where it is stricter than the IPC.
14 questionsPlumbing Mathematics
Offsets and travel, grade and fall, volume, unit conversion and the geometry behind pipe layout.
18 questionsBlueprint Reading
Symbols and abbreviations, scale, isometric risers and reading a plan set in order.
12 questionsInstallation & Troubleshooting
Diagnosing faults from symptoms: siphonage, noise, slow drainage, pressure loss and backflow.
14 questionsQuestion count by topic
| Topic | What it covers | Questions |
|---|---|---|
| Plumbing Fundamentals | Terminology, materials, joining methods and the vocabulary every other exam section is written in. | 16 |
| Water Supply Systems | Service and distribution sizing, pressure control, backflow prevention and hot water delivery. | 16 |
| Drainage, Waste & Vent (DWV) | Fixture unit loading, slope, stack and branch sizing, cleanouts and offsets. | 18 |
| Pipe Sizing & Materials | Diameter selection from flow and velocity, material properties, approved uses and support spacing. | 16 |
| Water Pressure & Flow | Static and dynamic pressure, friction loss, pump head and transient pressure. | 16 |
| Plumbing Fixtures | Flow and flush rates, clearances, mounting heights, flood level rims and minimum fixture counts. | 14 |
| Traps & Interceptors | Trap seal depth, prohibited trap types, trap arm limits and interceptor selection. | 14 |
| Venting Requirements | Vent types and selection, terminal location, sizing, wet and circuit venting, AAVs. | 16 |
| Plumbing Safety | Trenching and excavation, confined spaces, hot work, PPE and material safety law. | 14 |
| International Plumbing Code (IPC) | How the International Plumbing Code is organised, what its tables govern and where it departs from the UPC. | 16 |
| Uniform Plumbing Code (UPC) | How the Uniform Plumbing Code is organised, its sizing approach and where it is stricter than the IPC. | 14 |
| Plumbing Mathematics | Offsets and travel, grade and fall, volume, unit conversion and the geometry behind pipe layout. | 18 |
| Blueprint Reading | Symbols and abbreviations, scale, isometric risers and reading a plan set in order. | 12 |
| Installation & Troubleshooting | Diagnosing faults from symptoms: siphonage, noise, slow drainage, pressure loss and backflow. | 14 |
Your progress
Loading your saved progress…
Frequently asked questions
Where do these plumbing exam questions come from?
All of them are written for this site. Topic coverage follows the subject areas named in publicly posted examination content outlines from the ICC and from state licensing authorities, but no examination question is reproduced: those are copyrighted by the bodies that write them, and copying them would be both unlawful and useless, since real examinations are revised.
Are the code references in the answers accurate?
Each answer carries the code family, the edition and the subject of the provision it rests on. A section number appears only where the citation is known to exist, because section numbering shifts between editions and a plausible-looking invented citation is indistinguishable from a real one. Treat the references as pointers into your own copy of the adopted code rather than as a substitute for it.
What does 'flagged for review' mean on a question?
It means the technical content needs confirmation by a licensed reviewer before being relied on. Usually because the provision varies between the IPC and UPC, between editions, or between jurisdictions. 32 of the 214 questions carry that flag, and it is displayed with the explanation rather than hidden.
How many questions are there in each topic?
Between 12 and 18, depending on how much ground the topic covers. Drainage, waste and vent work and plumbing mathematics carry the most, because they carry the most weight on real examinations. The table on this page lists the exact count for every topic.
Which topics carry the most weight on a plumbing exam?
Drainage, waste and vent work is the largest single block on most journeyman outlines, with venting close behind it and water supply and distribution next. Those three plus pipe sizing and plumbing mathematics account for the bulk of a trade paper. Master outlines redistribute some of that weight toward code application, plan review and diagnosis. The topic table on this page shows how many questions we hold for each.
How many practice questions should I do a day?
Fewer than you might think, read more carefully than you might expect. Working twenty questions and reading every explanation, including the ones you got right, teaches more than working a hundred and checking only the score. The questions worth repeating are the ones you got wrong, which is what the retry queue is for.
Can I practise just one topic?
Yes. That is what the topic pages are for. Each has its own introduction, a list of what the topic actually tests, the mistakes that cost candidates marks, and a practice set with immediate feedback and full explanations.
Related pages
Free Plumber Practice Test
Start here. Mixed practice, progress tracking and every exam in one place.
Journeyman Plumber Practice Test
Full-length paper weighted toward installation and code application.
Master Plumber Practice Test
Longer paper with more design, plan review and diagnosis.
Plumbing Calculations Practice
Numerical exercises with tolerance checking and worked solutions.
Plumbing Code Practice Test
IPC and UPC structure, adoption and where the two codes diverge.
What this material is, and what it is not
- Every question here is written for this site. None is taken from a real examination, and no examination questions are reproduced: doing so would infringe the copyright of the bodies that write them.
- No practice exam on this site is a replica of an official examination. Question counts, time limits and pass marks are set by individual state licensing boards and their testing vendors, are not uniform, and have not been verified here. Topic coverage is modelled on publicly posted examination content outlines; timing and pass marks are our own practice settings. Your candidate bulletin is the authoritative source for the examination you will actually sit.
- Code references name the code family, the edition and the subject. Section numbers are given only where the citation is known to exist, and they move between editions : treat them as a pointer into your own copy of the adopted code, not as a substitute for it. What is enforceable where you work is the edition your jurisdiction has adopted, as amended locally.
- 32 of the 214 questions carry a visible “flagged for review” note identifying technical content a licensed reviewer should still confirm, usually because the provision varies between codes, editions or jurisdictions. The flag is shown with the explanation rather than hidden.
- Nothing here is a guarantee of an examination result, and no pass-rate figures are published on this site because we have no way to measure one honestly.