General Plumbing Regulations, Definitions, and Administration
Where the rules live
Idaho plumbing is regulated by the Idaho Plumbing Board within the Division of Building Safety (DBS). Questions come from three layers: the licensing statute, the Board's adopted rules, and the Uniform Plumbing Code (UPC) as amended for Idaho. Learn the architecture - administration chapter, definitions chapter, licensing sections - so you can locate a requirement instead of memorizing one edition's numbering. When a question says "the code," it means the edition currently adopted by rule.
Licensing and administration
- Apprentice, journeyman, master, and specialty credentials exist; the master is the party who contracts for plumbing and carries responsibility for supervision.
- A permit is required before installing, altering, or repairing plumbing, with narrow exemptions for minor repair work. The authority may be DBS or a local agency with delegated authority.
- Rough-in and final inspections are separate events. Work must not be covered before it is approved.
- Required tests typically include water distribution under pressure and drainage/vent systems under water or air test.
Definitions that earn points
- Accessible: can be reached without removing permanent construction. Readily accessible: can be reached without tools, panels, or climbing.
- Flood level rim: the edge of a fixture from which water overflows.
- Air gap versus air break: an air gap is a physical separation of supply from the receptor; an air break is a piped separation that still discharges below the fixture rim but above the drain.
- Developed length: distance measured along the centerline of pipe and fittings.
Worked example
A cleanout sits behind a screwed-on access panel in a finished wall. Is it accessible? Yes - removing a panel is not removing permanent construction. Is it readily accessible? No - a tool is needed. Answer with the exact defined term the question uses; the two terms are not interchangeable.
Traps
- Confusing DBS plumbing regulation with the local health department's food-service review.
- Deciding a permit is "probably not needed" for an alteration.
- Quoting an outdated UPC edition instead of the one Idaho has adopted.