Plumbing Practice Exam Questions — Flashcards

Plumbing exams for certifications like Journeyman or Master Plumber typically focus on your ability to interpret and apply the International Plumbing Code (IPC) or Uniform Plumbing Code (UPC). Questions generally fall into several core categories: 

1. Administrative & Regulatory
These questions test your knowledge of the legal side of plumbing. 

Permit Requirements: Which fixtures (like water heaters) require a permit and inspection for replacement.
Licensing Authority: Who is authorized to interpret code or apply for permits.
Safety Standards: Knowledge of OSHA rules and health/safety procedures. 

2. System Sizing & Math
You will be asked to perform calculations to ensure systems can handle demand. 

Drainage Fixture Units (DFUs): Calculating the total load on a system to determine the required pipe diameter for building drains or waste stacks.
Fluid Mechanics: Questions on water pressure (PSI), friction loss, and flow rates for different fixtures.
Sizing Charts: Using code-specific tables to determine the minimum size for traps, vents, and water service lines. 

3. Drainage, Waste, and Venting (DWV) 
This is often the largest section of the exam. 

Venting Methods: Identifying correct installations for circuit vents, stack vents, and common vents.
Traps and Cleanouts: Minimum trap seal depths (usually 2 inches) and the maximum distance between cleanouts (e.g., every 40-100 feet depending on the code).
Testing Procedures: Approved methods for leak testing, such as water, air, or smoke tests. 

4. Fixtures & Installation
Questions on how to correctly set and connect specific plumbing units. 

Accessibility (ADA): Minimum opening widths for shower doors (22 inches) and maximum reach distances for accessible faucets (25 inches).
Indirect Waste: Requirements for air gaps versus air breaks to prevent backflow from drainage systems.
Water Heaters: Proper installation of temperature and pressure relief (T&P) valves and discharge tubing. 

5. Materials & Joining Methods
Identifying the right materials for the job and how to connect them safely. 
Pipe Types: Usage of PVC, copper, cast iron, and PEX, including which are prohibited for specific uses like underground gas lines.
Joining Techniques: When to use dielectric unions to prevent corrosion between dissimilar metals (e.g., copper and galvanized steel).

Note: Answers may vary based on whether the IPC or UPC is applicable.