When separate sanitary and storm drainage systems are installed on the same property

While this option suggests a correct practice, it is not the complete answer as it merely reiterates the principle without specifying that the separate trenches are a requirement for sanitary and storm drainage systems. It lacks the essential context provided by the correct answer.

This option is incorrect as it contradicts plumbing regulations, which prohibit the installation of sanitary and storm drainage systems in the same trench. Doing so poses a risk of contamination and does not meet health and safety standards.

This choice is incorrect because it suggests a method of installation that is not compliant with standard plumbing regulations. Sanitary and storm systems cannot be in the same trench, regardless of elevation, due to the risk of cross-contamination.

This option is misleading as it implies a permissible distance between two systems in the same trench, which is not allowed per plumbing codes. Sanitary and storm drainage systems must be installed in separate trenches to ensure safety and compliance.