What is the minimum vertical separation required from the bottom of drip tubing to a limiting layer?

The minimum vertical separation required from the bottom of drip tubing to a limiting layer is set to ensure proper drainage and prevent contamination of the groundwater. A limiting layer, which may be comprised of restrictive soils or bedrock, could impede the flow of effluent from the drip tubing into the surrounding soil.

By maintaining a separation of 12 inches from the bottom of the drip tubing to this limiting layer, it allows for adequate infiltration of the effluent into the soil. This buffer zone ensures that the treated wastewater has enough space to be absorbed and filtered by the soil, which is critical for protecting water quality and preventing potential environmental issues.

Therefore, the specified vertical separation is a crucial design consideration in septic system installation, highlighting the importance of understanding soil dynamics and the behavior of effluent in the subsurface environment.