Plumbing licenses don't transfer between most states, trapping workers geographically

A master plumber licensed in Texas cannot legally work in California, New York, or most other states without re-applying, re-testing, and paying $50-400 in new fees -- even after 20+ years of experience. Only a handful of states have reciprocity agreements, and those agreements are narrow (e.g., Delaware only recognizes Connecticut, Iowa, and Maryland). The people hurt are journeyman and master plumbers who want to relocate for family, cost of living, or disaster-response work, and plumbing contractors who cannot expand across state lines without hiring entirely new licensed crews. In a trade already short 550,000 workers, this geographic lock-in prevents the labor market from self-correcting by flowing workers to where demand is highest. The problem persists because plumbing codes vary by state and municipality (IPC vs UPC vs local amendments), and each licensing board is an independent bureaucracy with no federal coordination. Each board has a financial incentive to charge exam and application fees rather than accept another state's credential.