Which soil condition is least favorable for installing a mound system?

Saturated clay soils present the least favorable condition for installing a mound system due to their high water retention and low permeability. In a mound system, the primary goal is to ensure that effluent from a septic system can effectively percolate through the soil and be absorbed into the surrounding environment.

Clay soils, particularly when saturated, create a situation where water cannot move through the soil matrix efficiently. This can lead to surface water pooling and potential failure of the mound system, as the effluent may not be adequately treated before reaching groundwater or may back up into the system, causing serious issues with drainage and odor.

In contrast, loamy soil and sandy soil are generally good candidates for mound systems as they provide better drainage characteristics, allowing for proper absorption of treated effluent. Well-drained rocky soils also promote drainage, but may require careful assessment to ensure that the rocks do not impede the effective installation of necessary piping and distribution systems. Thus, saturated clay soils are clearly the least favorable option due to their inherent properties that hinder proper effluent absorption and treatment.