Which type of rock generally holds more water, sedimentary or igneous?

Sedimentary rocks are the type that generally holds more water compared to igneous rocks. This is primarily due to their porosity and permeability characteristics. Sedimentary rocks, such as sandstone and limestone, are formed from the accumulation and compaction of sediments over time. These structures often contain numerous spaces or pores between the particles, allowing them to effectively store water.

In contrast, igneous rocks, which are formed through the solidification of molten material, typically have a much denser and less porous structure. The crystal arrangement in igneous rock reduces the space available for water to occupy, leading to lower water retention capabilities.

Metamorphic rocks develop from existing rocks that undergo changes due to heat, pressure, and mineral alteration. While they may have some capacity to hold water, they generally do not compare to sedimentary rocks in this respect.

The idea that both types hold equal water does not take into account the fundamental differences in their geological formation and structure. Thus, sedimentary rocks are recognized for their superior ability to store water, making them essential in aquifer systems and groundwater supply.