Most states and local areas require plumbers to have a license, which is typically available at two levels. After completing an apprenticeship, a plumber becomes a journey worker, legally able to work alone. With additional coursework and experience, a plumber can pass exams to become a master plumber. Some companies require master status, and master plumbers also generally earn more. Knowing what kind of questions to expect will improve your chances of passing these exams.

Pipe Sizing Charts

One section of the examination tests the plumber’s ability to properly size different types of pipes according to state sizing charts. The exam provides the sizing charts for reference, and the questions determine whether or not the applicant understands how to read the charts, not memorize them. The pipe sizing chart section of the test contains four sub-sections: fuel gas pipes, water pipes, fuel gas fired appliance vent pipes and drainage pipes. In each sub-section, the plumber receives a drawing or diagram and must determine the proper pipe sizes based on the information in the charts.

Mathematics Questions

The mathematics section of the exam tests the plumber’s ability to make correct calculations during the installation and design of plumbing systems. The applicant receives the conversion and sizing tables, formulas, a calculator and any other necessary information. The questions are similar to the following: “If a sewer ditch must be 148 feet in length and the pipe is to be installed at a 2 percent grade, what is the total amount of fall?” and “There is a copper water riser that is 6 inches in diameter and 50 feet tall that is full of water. How many gallons of water are in the pipe?" The questions in the mathematics section of the exam are in a multiple-choice format with four possible answers for each question.

OSHA Code

One section of the exam tests the plumber’s knowledge of the Occupational Safety and Health Administration's federal code regulations. The applicant must be knowledgeable of the safety regulations regarding hand and power tools, welding and cutting, excavations, scaffolding, and personal protective and life support equipment. A question similar to those in this section is: “Scaffolds and their surrounding components must be able to support at least how many times the maximum intended load?” Each question in the OSHA code section of the exam comes in multiple choice format with four answer options per question.