What is meant by 'functional drainage'?

Functional drainage refers to the effectiveness of a drainage system in transporting water away from areas where it could cause issues, such as from roofs, driveways, or landscaping features. The concept emphasizes that a drain must be able to perform its function within an acceptable time frame, ensuring that water does not accumulate and create potential problems, such as flooding or damage to structures.

Understanding functional drainage is crucial for a home inspector, as it affects the overall performance of a property's water management system. Being able to identify whether a drainage system drains water efficiently is vital for evaluating its condition and making recommendations for maintenance or repairs. In the context of the given choice, focusing on the time aspect indicates that the drain must not only exist but must also work effectively in a timely manner to maintain the integrity of the property.