Plumbers in Arizona are licensed as contractors by the Arizona Registrar of Contractors. Plumbers design, install and repair piping, fixtures, septic tanks and full water supply systems. The Arizona Registrar of Contractors grants two types of general plumbing licenses: a C-37R license, which covers residential plumbers; and a L-37 license, which covers commercial plumbers. For both licenses, you will be considered a contractor, meaning that you must also be registered as a business with Arizona and your municipality before you apply for your license.

Gain experience in the plumbing trade. You must have four years of documented experience in the plumbing trade to qualify to apply for a license. A common way to gain this experience is through an Arizona-approved apprenticeship program (see Resources). Alternately, you can gain the experience by working under the supervision and guidance of a licensed plumber who you find on your own.

Sit for your exams. Exams are administered online through the third-party exam provider, Prometric. You must sit for a business management exam and one of the residential or commercial plumbing trade exams. The business management exam consists of 80 multiple choice questions and you are allowed two-and-a-half hours to complete it. You have four hours to write the plumbing trade exam, which consists of 85 questions. You must get a grade of 70 percent to pass. The fee for the exams is $120, as of 2010. Contact Prometric to schedule your exams.

Prometric 1260 Energy Lane St. Paul, MN 55018 800-899-4089

Apply for your C-37 or L-37 license. Once you have passed your exam, you can apply for a license. You can download and print a license application from the Arizona Registrar of Contractors website (see Resources). You must include detailed information about yourself, your business and your work experience. You must also attach documents verifying that you have completed the required four years of work experience and passed your trade exam. To work as a plumber, you must also have a license bond and include it with your application. This can take the form of a surety bond, cash bond or certificate of deposit. You must get a license bond of $1,000 for the C-37 license and $2,500 for the L-37 license. You must include your application fee: $320 for a residential license and $645 for a commercial license. Once complete, send the full application package to the Arizona Registrar of Contractors.

Arizona Registrar of Contractors 3838 N. Central Ave., Suite 400 Phoenix, AZ 85012-1946