A mound or soil substitution drainfield is often utilized when?

A mound or soil substitution drainfield is often utilized when existing soils will not provide adequate treatment due to insufficient depth or poor texture. This type of system is specifically designed to overcome the limitations of the native soil, which may not have the necessary permeability or filtering qualities to adequately treat wastewater. By creating a raised mound filled with suitable materials, the design ensures that effluent can be sufficiently treated before percolating into the soil below, providing a viable solution for sites with restrictive soils.

In contrast, while excess water on the property or a general need for additional drainage may seem logical reasons to implement a mound system, they do not directly address the fundamental issues of soil treatment capability. Additionally, building codes requiring a certain system could potentially influence the choice of a mound, but the primary purpose of such a system is to remedy inadequate soil conditions for treating effluent effectively.