Commercial plumbing vs. Traditional Methods: Which Wins? Refer to the plumbing license application forms for further details. The NSW Office of the Clerk of the Local Court (the Office) oversees the state's plumbing license system. You must apply for a license and register with the Office if you wish to work as a licensed plumber in New South Wales.You can apply for a building permit in person at 201 North Main Street or online at www . Where is the...