What is saprolite?

Saprolite is best described as soft, decomposed rock that has been formed through the process of chemical weathering. This weathering breaks down the original rock, often granite or other parent materials, into a softer, more clay-like consistency while retaining the structure of the rock. It typically contains a high degree of alteration and is found beneath the surface layer of soil.

The significance of saprolite in the context of onsite wastewater systems lies in its ability to affect soil drainage and the movement of effluent. Understanding its properties is essential for designing effective wastewater systems, ensuring that they do not contaminate groundwater and function properly based on the underlying geology.

While solid rock does exist, saprolite specifically refers to the decomposed and altered material. Loose soil with high clay content does not capture the essence of saprolite, which is derived from weathered rock rather than directly being categorized as soil. Granite rock formation is a type of solid rock that can eventually become saprolite through weathering, but saprolite itself is a distinct product of that process.