Plumbers must show their ability as installers of plumbing systems to an official executing board prior to being issued a license. A plumbing code which is technically perfect is worthless if its provisions are not noticed and applied. The issuance of a license by a community specifies that the holder is qualified both theoretically and practically and that their technical knowledge is enough to maintain the standards of the code.
Is licensing intended to prevent anyone but a plumber from doing sanitation work? NO… Licensing prohibits the negligent, incompetent person from jeopardizing the health of your family, neighbors, and community. Any person may do the work who has adequate knowledge to do it in a safe manner, so long as the Rules and Regulations of the plumbing and sanitation code are observed. However, those wishing to do this work must prove their ability by taking out a license and passing an exam.
Many states require that, like a physician, nurse, dentist or pharmacist, anyone whose work affects the public health and safety shall have adequate knowledge and training. No one wants a “quack doctor” to treat his family or a “counter clerk” to fill his prescriptions. For exactly the same reasons, one does not want a “handyman” to do work in his home, office, or factory which can negatively affect the health of his family, his employees, or his neighbors.
Done improperly, this work would probably need to be corrected at the time the property changed hands, which means paying twice for the same work. Additionally, licensed plumbing professionals are held to a certain standard of accountability – meaning they must perform their work correctly or risk being liable for accidents, damages, illnesses, etc. caused by improperly-performed jobs – and must often hold some form of bond or insurance that can protect you if something happens.
So, while that small bathroom remodel might seem like a great, inexpensive DIY project, it’s probably wisest to spend a little more and make sure a licensed plumbing contractor performs the work.