When choosing a licensed plumber in Melbourne, check the plumber’s details on the Victorian Building Authority (VBA) practitioner register and ask for their registration or licence number. Confirm they are insured, provide a written quote, and explain whether the work includes any required compliance certificates or permits. For gasfitting, use a plumber with the appropriate gasfitting authorisation, and avoid anyone who cannot show current credentials. For urgent leaks or sewage issues, shut off the water if safe and contact a qualified professional; the VBA or your local council can help clarify requirements.