Materials required by the code that comply with a referenced standard must be listed by which agency?

The correct response highlights the importance of third-party certification in ensuring that materials used in plumbing meet the required codes and referenced standards. Third-party certification involves an independent organization that evaluates and certifies products based on rigorous testing and compliance with industry standards. This process provides assurance to both regulators and consumers that the materials have been thoroughly assessed for safety and performance.

Having materials certified by a recognized third-party organization lends credibility to their compliance with the plumbing code. These certifications typically include detailed reports and documentation that signify the material's qualifications. This is essential in maintaining safety and compliance in plumbing installations.

In contrast, evaluation services and accreditation services may play roles in assessing standards or recognizing organizations but do not specifically focus on the certification of individual materials. Third-party testing refers to the procedures and tests carried out, but it is the certification that verifies that these tests meet the necessary standards for compliance. Therefore, the necessity for materials to be third-party certified aligns perfectly with the requirement for safety and reliability in plumbing installations.