What is placed on top of the drain rocks in an Absorption Field?

In an absorption field, the placement of a filter fabric on top of the drain rocks serves several essential purposes. This non-woven fabric acts as a barrier that prevents soil particles from clogging the void spaces in the gravel, which are necessary for proper drainage and absorption of effluent.

The filter fabric allows water to flow through easily while preventing larger soil particles from penetrating and filling the gaps within the drain rocks. This is crucial for maintaining the efficiency of the absorption field, as it ensures that wastewater is adequately filtered and treated as it percolates into the surrounding soil.

Using a protective cover, additional gravel, or a concrete slab would not provide the same function as the filter fabric. A protective cover might impede water flow rather than facilitate it, while additional gravel could disrupt the designed drainage patterns. A concrete slab would obstruct water movement entirely. Thus, the filter fabric is specifically designed to enhance the function and longevity of the absorption field.