When the water table is at 6 inches, what formation should the absorption bed be?

When the water table is at a shallow depth, such as 6 inches from the surface, a mounded system is typically the most appropriate choice for an absorption bed. This design involves raising the absorption area above the natural ground level, which helps improve the disposal of effluent by increasing the distance between the leach field and the water table.

A mounded absorption bed takes advantage of gravity and allows the effluent to better filter through the soil before reaching the water table. This configuration is beneficial because it helps to prevent flooding of the system, promotes better aeration and drainage, and enhances the treatment process, ultimately leading to more effective wastewater management.

In contrast, other options such as flat or excavated designs would not provide adequate separation from the high water table and could result in poor effluent treatment or system failure. A depressed system, while it may seem like it would allow for the management of the water table, could lead to saturation of the absorption area and insufficient treatment, as it would be positioned below the natural ground level and would be prone to flooding.