What materials are prohibited for use in drainage systems?

Foreign materials are prohibited for use in drainage systems because they can lead to blockages, reduced efficiency, and potential damage to the plumbing infrastructure. Drainage systems are designed to transport wastewater and stormwater safely away from buildings and infrastructure. When foreign materials enter these systems, they can disrupt the flow of water, create clogs, and hinder the overall operation of the drainage system.

For instance, foreign materials might include items like food waste, plastic containers, or even construction debris, which are not intended to be part of the drainage system. Such items can accumulate and create serious issues, leading to costly repairs and maintenance. This is why regulations specifically discourage the introduction of anything not designed for drainage applications, ensuring that systems remain clear and function properly.

The other choices involve materials that can be permissible under certain conditions. Approved plastic pipes are often used in drainage due to their lightweight and resistance to corrosion. Metal pipes can also be part of a drainage system where applicable, while flexible tubing may be used in specific applications as long as they meet relevant codes and standards.