What characteristics of a rock layer would allow it to hold water?

porosityWhat characteristics of a rock layer would allow it to hold water?
primary and secondary porosity. Permeability is the ability of that water to be transmitted from one place to another. For example clays have a huge porosity, but very bad permeability. Secondary permeability is the measure of other physical structures in a rock or admixture that allows for storage of water in spaces not primary to the fabric of the formation. Fractures, vugs, joints and conduits are examples of secondary porosity features.What characteristics of a rock layer would allow it to hold water?
Porosity along with permeability. Porosity is the ratio of void space to total volume, expressed as a percentage. Permeability is the connectiveness of the pores. If the pores are not connected to other pores or the outside water source then holding and transmitting of water will not happen.