In terms of placement, what should be the relationship between the bottom of the subsurface system and the limiting layer?

The correct answer is based on the established guidelines for the installation of subsurface systems in relation to limiting layers, which typically refers to the lower boundary of soil or rock that can restrict the movement of water.

Positioning the bottom of the subsurface system a minimum of 2 feet above the limiting layer is crucial for effective drainage and to prevent potential contamination of groundwater. This distance allows adequate space for water to percolate and be treated within the soil before reaching the limiting layer, ensuring that the effluent from the system does not pool or create issues such as high groundwater levels that could lead to system failure.

This 2-foot minimum is also in accordance with various regulatory standards that dictate suitable separation distances to promote both soil health and the effectiveness of wastewater treatment processes. Inadequate separation can lead to improper system function and increased risk of environmental or health hazards.

Understanding this relationship emphasizes the importance of proper planning and site evaluation when installing a subsurface sewage system, as it is crucial for both the success of the system and compliance with public health regulations.