What must be installed to prevent surface water from flooding the drain field?

Proper grading and drainage are essential for protecting the drain field from flooding caused by surface water. When a septic system's drain field is overwhelmed by surface water, it can lead to the failure of the system, as excess water can saturate the soil and prevent proper filtration of wastewater. By ensuring that the area surrounding the drain field is graded appropriately, water can be channeled away from the system, thus reducing the risk of flooding. This grading should direct drainage towards natural low areas or designated drainage structures, ensuring that the drain field remains functional and sanitary.

Other options, while they may seem relevant, do not address the primary need for managing surface water to protect the drain field effectively. Underground pipes might assist with the movement of water but do not specifically prevent flooding. Storage tanks could mitigate excess water temporarily but do not solve the problem of surface water drainage. Water barriers may redirect some water but are not a comprehensive solution to manage grading and overall drainage effectively.