Plumber license requirements in Iowa.
Iowa licenses plumbers statewide through the Plumbing and Mechanical Systems Board, now administered by the Department of Inspections, Appeals and Licensing. Both the journeyman and master exams are open book, and licenses run on a three-year cycle.
What Iowa requires.
Journeyman Plumber
Requires a registered apprenticeship (with US Department of Labor Office of Apprenticeship and sponsor identification numbers) or at least four years of apprentice-like on-the-job training.
Master Plumber
Requires holding the journeyman plumber license for a minimum of two years.
Getting the Journeyman Plumber
- Journeyman: provide a US Department of Labor Office of Apprenticeship identification number and sponsor identification number, or show at least four years of apprentice-like or on-the-job training
- Journeyman exam: 100 questions, open book, three hours, 75% to pass
- Master: hold the journeyman license for at least two years
- Master exam: 125 questions, open book, five hours
Renewal: Licenses renew every three years, and plumbers must complete at least 8 hours of board-approved continuing education as a condition of renewal.
The official board
Iowa Plumbing and Mechanical Systems Board — Department of Inspections, Appeals and Licensing
Visit the boardVerified 2026-08 against the sources below. Licensing rules change — confirm with the board before relying on this page.
Iowa plumbing licensing FAQ.
Do you need a license to do plumbing work in Iowa?
Yes. Iowa licenses plumbers statewide through the Plumbing and Mechanical Systems Board, which issues journeyman and master plumber licenses.
How do you qualify for the Iowa journeyman plumber exam?
Provide a US Department of Labor Office of Apprenticeship identification number and sponsor identification number, or document at least four years of apprentice-like or on-the-job training.
Are Iowa plumbing exams open book?
Yes. The journeyman exam is 100 questions over three hours with a 75% passing score, and the master exam is 125 questions over five hours. Both are open book.
How often do Iowa plumbing licenses renew?
Every three years, with at least 8 hours of board-approved continuing education required as a condition of renewal.
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