Why licensing matters
A plumbing license is how states verify that you know what you're doing before you work on systems that affect public health and safety. Licensed plumbers can pull permits, take on larger commercial jobs, and charge more for their work. Operating without a license in a state that requires one can mean fines, stopped work, and liability exposure.
Types of plumbing licenses
Most states have at least two tiers: Apprentice/Helper (supervised work, no exam), Journeyman Plumber (independent work, exam required), and Master Plumber (run a business, supervise others, pull permits). Some states add a Contractor or Business License on top of the trade license.
What's required to get licensed
Requirements vary by state but generally include: a minimum number of hours of supervised field experience (typically 4,000–8,000 hours for journeyman), passing a written exam on plumbing codes and practices, proof of ID and work history, and an application fee. Some states also require continuing education to maintain your license.
How to find your state's requirements
Every state has a licensing board for contractors and tradespeople. Search for "[your state] plumbing license requirements" to find the official board. They'll have the exam schedule, application forms, and fee schedule. The exam is usually administered by a third party like Prometric or PSI Exams.
Running your business while you're licensed
Once you're licensed, you're running a real business. That means professional invoicing, written estimates, and keeping records. BIG INVOICE is free to download — a simple way to invoice clients from your phone without a learning curve.