Plumbing Code, Rules, and Licensing Requirements
Where the rules come from
Oklahoma administers plumbing through a state licensing statute, board rules, and an adopted model plumbing code (the IPC family) modified by state and local amendments. Expect questions on hierarchy: statute, then board rules, then the adopted code, then local ordinance. A local amendment may be more restrictive but cannot relax state licensing requirements. The authority having jurisdiction (AHJ) interprets and enforces, and approved plans do not excuse code violations discovered in the field.
Licensing tiers
Know apprentice, journeyman, and master/contractor. The licensed contractor of record contracts for the work, pulls permits, and is responsible for everyone on the job. A journeyman cannot pull a permit on someone else's behalf or moonlight as a company. Insurance, bonding, and continuing education are renewal conditions, not optional extras. "Helping a friend for cash" and unlicensed advertising are standard violation scenarios.
Permits and inspections
Rough-in, top-out, and final are separate inspection events. Concealing work before rough-in approval is a violation, and rough-in plumbing must be tested (water or air) before cover. Water heater replacements, repipes, and new services generally require permits; minor repair allowances are narrow.
Traps
Questions that assume the inspector "may waive" a requirement, that a homeowner exemption covers a rental property, or that a licensed employee can legally contract directly with the owner. Also watch code-edition questions: the exam quotes the edition adopted as of a stated date.
Rule of thumb
One permit can cover multiple inspections. Never guess the fee schedule or inspection sequence - exam items usually state the AHJ's rule, and if they do not, the conservative answer is "ask the AHJ in writing before proceeding."