Authority having jurisdiction (AHJ)—An organization, office, or individual responsible for enforcing the requirements of a code or standard, or for approving equipment, materials, an installation, or a procedure.
Potable water—Water for human consumption.
Mechanical systems—Heating, ventilation, air-conditioning, and refrigeration (HVAC-R) equipment.
Journey-level plumber—A licensed plumber usually requiring at least two years of experience and passing at least one exam, sometimes both a written and hands-on exam.
Master plumber—Normally, a licensed plumbing contractor who can bid jobs. Becoming a master plumber typically requires at least four years of experience and passing at least one exam—sometimes a plumbing code exam and a business and law exam.
Specialty solar license—A limited license used in some states to allow individuals and contractors to work on, for example, only solar water and pool heating systems.