At what slope percentage are soil absorption systems typically prohibited?

Soil absorption systems, which are crucial components of septic systems, are typically prohibited at a slope percentage greater than 25%. This is primarily because steep slopes can lead to several issues that jeopardize the effectiveness and safety of the system.

When the slope exceeds this limit, the gravitational forces can cause rapid runoff rather than allowing adequate absorption of wastewater into the soil. This can lead to poor infiltration, increased erosion, and potential contamination of surface water or groundwater, as the effluent may not have enough time to properly filter through the soil layers.

Additionally, steeper slopes can complicate the installation of the absorption system and increase the risk of system failure. Thus, maintaining a slope of 25% or less ensures that soil absorption systems function effectively and protect the environment and public health.