Colorado Plumbing Code, Permits, and Inspection
Two layers of code, one inspection sequence
Colorado adopts a statewide plumbing code built on the International Plumbing Code, with state amendments plus local amendments layered on top. That structure is the biggest exam trap: when a question asks which rule governs, the locally adopted - and generally stricter - amendment applies, and you should not assume every jurisdiction enforces identical text. Always confirm with the authority having jurisdiction (AHJ).
Permits come first. Do not begin permit-required work before the permit is issued. Typical permit work includes new construction, additions, repiping, sewer and water service lines, and water heater replacement; minor repairs such as a faucet or a stop may be exempt, but verify locally. Permits are pulled by the licensed contractor. Journeymen and master plumbers are licensed through the state plumbing board, and apprentices work under supervision.
Know the inspection sequence, because questions describe a stage and ask what comes next: underground or slab inspection before cover, rough-in after piping is complete and before walls close, top-out, then final after fixtures and equipment are set and tested. DWV systems are tested with water at 10 ft of head or a listed air test (about 5 psi held 15 minutes); water supply piping is tested at working pressure.
Worked example: if drywall goes up before the rough-in inspection, expect a failed inspection and an order to expose the piping. Schedule the rough-in before the walls close.