Existing plumbing systems must be brought into compliance with the IPC if the system is _____.

The correct answer highlights that an existing plumbing system must be brought into compliance with the International Plumbing Code (IPC) if the system poses a hazard to property. This requirement ensures that any plumbing system that presents risks to safety, health, or property is updated and brought up to current standards to mitigate potential dangers.

When a plumbing system is identified as a hazard, whether due to outdated materials, improper installation, or deterioration, addressing the issue in line with current code requirements is crucial. This ensures the safety of inhabitants, protection of the property, and compliance with legal standards.

Bringing a hazardous plumbing system into compliance not only rectifies immediate risks but also promotes the overall integrity and reliability of the plumbing infrastructure. This reflects a commitment to maintaining safety and compliance with established plumbing practices as stipulated in the IPC.