What must each length of pipe, fitting, trap, fixture, and device in a plumbing system be marked with?

In plumbing systems, it is essential for each length of pipe, fitting, trap, fixture, and device to be clearly marked to ensure proper identification and compliance with safety and building codes. The correct choice highlights that these components should include information such as weight and quality, as well as the maker's mark.

Weight is crucial for determining how much support a plumbing system needs, especially in terms of structural integrity and the load-bearing capacity of the materials used. Quality indicators, marked by the manufacturer, provide assurance that the materials have passed necessary tests and standards, ensuring reliability and durability.

The maker's mark is equally important since it allows for tracking the origin of the product, enabling plumbers and regulators to trace back to the source in case of recalls or safety issues. This marking is vital for maintaining the standards of quality that are expected in plumbing systems.

While other options may include relevant information, they do not emphasize the importance of both weight and quality alongside the identification of the manufacturer, which are essential in ensuring a safe and compliant plumbing installation.