What a plumbing license actually requires

A plumbing license is a credential issued by your state or local government that allows you to work as a plumber — installing, repairing, and maintaining water and drainage systems in buildings. Unlike a driver's license, there is no single national plumbing license. Each state sets its own rules, and some states let cities or counties set additional rules on top of that. What you need to do depends entirely on where you live and work.

Most states require plumbers to pass a written exam, complete a certain number of hours working under a licensed plumber, and pay a fee. The hours of hands-on work — called an apprenticeship or on-the-job training — typically take several years. Some states require a high school diploma or GED; others do not. Some require you to pass a background check; others do not. The variation is real and significant, so your first step is to find out what your specific state or city demands.

Key Takeaways

  • Plumbing license requirements vary by state and sometimes by city, so you must contact your state's licensing board or plumbing inspector's office to learn what applies where you live.
  • Most states require you to work 4,000 to 10,000 hours under a licensed plumber before you can sit for the exam, which usually takes 4 to 5 years of full-time work.
  • You will need to pass a written exam that covers plumbing codes, safety, and practical knowledge specific to your state or region.
  • After you pass the exam and meet the hours requirement, you pay a fee and receive your license, which typically must be renewed every 1 to 3 years depending on your state.

Finding your state's specific requirements

Start by searching "[your state] plumbing license requirements" or "[your state] plumbing board." Most states have a licensing board, plumbing inspector's office, or division of occupational licensing that publishes the exact rules online. Some states call it the State Board of Plumbing Examiners; others call it the Department of Labor or Department of Professional Regulation. The name varies, but the office exists in every state.

When you find the right office, look for a document called the "plumbing code," "licensing requirements," or "apprenticeship standards." This document will tell you how many hours you need, what type of work counts toward those hours, whether you need a high school diploma, and what the exam covers. Write down the specific numbers — they differ. Some states require 4,000 hours; others require 8,000 or 10,000. Some require 144 classroom hours; others require 300. These numbers matter because they determine how long the process takes.

If you cannot find the information online, call the office directly. A staff member can tell you the current requirements and point you to the right form or website section. Many offices also have a phone line specifically for questions about apprenticeship and licensing.

The apprenticeship: where you actually learn the trade

In most states, you cannot sit for the plumbing license exam until you have completed an apprenticeship — a period of working under a licensed plumber while learning the trade. This is not optional in most places, and it is not something you can skip by taking classes instead. The apprenticeship is the core requirement.

An apprenticeship typically lasts 4 to 5 years if you work full-time. During that time, you work on actual plumbing jobs — installing pipes, fixing leaks, running water lines, connecting fixtures — under the supervision of a licensed plumber. You are paid for this work, though the pay is usually lower than what a fully licensed plumber makes. At the same time, you attend classroom instruction, usually one or two nights a week or one day a week, depending on the program. The classroom covers plumbing codes, blueprint reading, safety, and the science behind how water and drainage systems work.

To start an apprenticeship, you typically need to find a plumbing company or contractor willing to hire you as an apprentice. Some large companies have formal apprenticeship programs; others hire apprentices informally. You can also look for union apprenticeships through the United Association of Plumbers and Pipefitters, which runs formal programs in many states. Union apprenticeships are structured, paid, and often include health insurance, but they are competitive to get into.

Classroom hours and exam preparation

While you are working as an apprentice, you will attend classroom instruction. The number of hours required varies by state — some require 144 hours total, others require 300 or more — but the classes cover the same general topics everywhere: local plumbing codes, how to read blueprints, water pressure and flow, drainage systems, safety practices, and business practices if you plan to own your own company.

Some apprenticeships include classroom time as part of the program, meaning your employer or union pays for it and you attend during work hours or scheduled evenings. Others require you to find and pay for your own classes at a vocational school or community college. Check your state's requirements to see whether classroom hours are included in your apprenticeship or whether you need to arrange them separately.

Once you have completed your apprenticeship hours and classroom time, you become may be able to access to sit for the licensing exam. The exam is written and covers the plumbing code used in your state or region, safety practices, and practical knowledge about how plumbing systems work. Some states use a national exam; others write their own. The exam usually takes 3 to 4 hours and costs between $100 and $300 to take. You can usually take it multiple times if you do not pass on your first attempt.

Passing the exam and getting your license

To pass the exam, you need to score above a certain percentage — usually 70 to 75 percent, depending on your state. The exam tests whether you understand the plumbing code well enough to work safely and legally. You will see questions about code violations, how to size pipes for different fixtures, how to install traps and vents correctly, and what to do in common problem situations.

Study materials are usually available from your state's licensing board or from test prep companies that specialize in plumbing exams. Many apprenticeship programs include exam prep as part of their classroom instruction. If you fail the exam, you can retake it after a waiting period — usually 30 days — and most states let you take it as many times as you need.

Once you pass the exam, you submit your passing score, proof that you completed your apprenticeship hours, and a fee to your state's licensing board. The fee is typically between $50 and $300. Within a few weeks, you receive your plumbing license. This license allows you to work as a plumber in your state or the specific jurisdiction that issued it.

License renewal and continuing education

Your plumbing license is not permanent. Most states require you to renew it every 1 to 3 years, depending on the state. Renewal usually involves paying a fee — typically $50 to $200 — and sometimes completing continuing education hours. Continuing education means taking classes or workshops to stay current with changes to the plumbing code or new techniques and materials.

Some states require 8 to 16 hours of continuing education per renewal period; others require none. Check your state's renewal requirements when you first get your license so you know what to expect. Many states send renewal notices by mail or email, and you can renew online. If you let your license expire, you will need to reapply and may have to retake the exam or complete additional hours, depending on how long it has been expired.

Journeyman, master, and specialty licenses

Most states have more than one level of plumbing license. The first level is usually called a journeyman plumber license, which is what you get after completing your apprenticeship and passing the exam. A journeyman can work on plumbing jobs but typically must work under the supervision of a master plumber or be directly responsible to a property owner.

A master plumber license is a higher level that allows you to own your own plumbing business, supervise other plumbers, and sign off on work. To get a master license, you usually need to have worked as a journeyman for a certain number of years — often 2 to 5 years — and pass a more difficult exam. Some states also offer specialty licenses for specific types of plumbing work, such as gas fitting or medical gas installation.

The requirements for each level are set by your state, so check your state's licensing board website to see what levels exist and what each one allows you to do.

Frequently Asked Questions

Do I need a high school diploma or GED to become a plumber?

Requirements vary by state. Some states require a high school diploma or GED; others do not. Check your state's apprenticeship standards to see whether education is a requirement where you live. If it is required and you do not have one, you can pursue a GED before explore for an apprenticeship.

Can I get a plumbing license in one state and use it in another?

No. Plumbing licenses are issued by individual states and are valid only in that state or the specific jurisdiction that issued them. If you move to another state, you will need to meet that state's requirements, which may be different. Some states have reciprocity agreements that allow licensed plumbers from other states to transfer their license with less work, but this is not common. Contact the new state's licensing board to find out what you need to do.

How much does it cost to get a plumbing license?

The direct costs — exam fees and license fees — typically total $150 to $500. However, the apprenticeship itself is the main cost in terms of time. You will spend 4 to 5 years working and attending classes. During that time, you are paid, but usually less than a fully licensed plumber. The total cost depends on whether your apprenticeship includes paid classroom time or whether you pay for classes yourself.

What if I already have plumbing experience but no formal apprenticeship?

Most states require the formal apprenticeship hours regardless of experience. However, some states allow you to count certain types of work experience toward the apprenticeship requirement if you can document it. Contact your state's licensing board to ask whether your experience can be credited and what documentation you need to provide.

How long does the whole process take?

The apprenticeship typically takes 4 to 5 years of full-time work. After that, you take the exam, which you can usually do within a few weeks. So the total time from starting an apprenticeship to holding a license is usually 4 to 5 years, assuming you pass the exam on your first attempt.