Plumbing is growing faster than most other occupations in the U.S., with the field expected to expand 26 percent between 2010 and 2020, according to the Bureau of Labor Statistics. Some employers are reporting challenges in finding qualified plumbers, and many workers are nearing retirement, improving prospects for new plumbers. The median pay for plumbers nationwide was just under $47,000 in 2010. States and cities have varying licensing requirements.
Find out what licenses you need by checking with your state and local licensing boards. You may need a contractor's license and a business license. For example, if you want to work in the city of Miami, Florida, you need either a state of Florida or Miami-Dade County contractor's license and a city of Miami certificate of use. In New York, applicants are tested and licensed at the local level but must register with the state. Regardless of the state, you will probably initially get a journeyman's license, then progress over time to a master plumber's license.
Check with the licensing boards to see what the requirements are for a plumbing contractor's license. Typical requirements include two to five years of experience as an apprentice and the passing of an exam that tests plumbing skills and familiarity with local plumbing codes. States such as Colorado maintain basic categories for plumber's licenses: residential plumber, journeyman and master plumber. Other states, such as Washington and Idaho, offer licenses in more specific categories such as medical gas, water pump, pipefitting, appliance and mobile home hook-up.
Complete a program at a technical school. Take welding courses if you want to work as a pipefitter or steamfitter.
Finish an apprenticeship program with a business or union. These programs typically require 1,700 to 2,000 hours of paid on-the-job training.
Fill out an application for the plumbing category you're interested in and pay the application fees. Fees range from about $100 to more than $450 in California, as of 2012.
Take the plumbing exam, if required. A key resource for the exam is the International Plumbing Code, an International Code Council publication. Some states allow reference materials during the tests. As part of the process, states may fingerprint you and, for a master's plumber license, ask you to prove you meet liability insurance requirements. A typical requirement is $300,000 of coverage.
Find out what the continuing-education requirements are to maintain a plumbing license in your area by checking with your state and local licensing boards. Also ask if your state has reciprocal agreements with neighboring states that would allow you to use your license in those states. For example, Idaho has such agreements with Washington, Oregon and Montana.