What document must the medical officer of health or secretary-treasurer issue to sewage system inspectors?

The correct document that must be issued to sewage system inspectors by the medical officer of health or the secretary-treasurer is a certificate of appointment. This certificate serves as an official designation that empowers the inspectors to carry out their duties related to sewage systems. It reflects that the inspectors have been formally recognized and authorized to perform inspections and ensure compliance with relevant health and safety regulations.

This appointment is crucial as it establishes accountability and sets the legal framework within which the inspectors operate. By receiving this certificate, inspectors gain the credentials necessary to enforce standards, assess the functionality and safety of sewage systems, and protect public health.

Other documents mentioned, such as a building permit, a certificate of compliance, or an inspection report, serve different purposes in the construction and regulatory process and do not specifically authorize an inspector's role in sewage systems. A building permit, for instance, is typically related to the approval of construction projects; a certificate of compliance indicates that a structure meets regulatory requirements, and an inspection report details findings from an inspection. None of these documents fulfill the need for an official appointment solely for sewage inspectors, which is why the certificate of appointment is the correct answer.