Some of the rock formations of North and mid Wales are made up of hard very well-cemented sandstone, interbedded with hard mudstone and siltstones. These rocks have low inter-granular porosity and permeability, with water movement occurring through secondary fractures and faults.
Small volumes of ground water for household use have historically been obtained from springs and shallow wells into the overlying superficial deposits or the uppermost few meters of weathered bedrock, which often run dry in the summer months.
For ground water abstraction from a bore hole encountering water-bearing fractures is critical low permeability rocks. these fractures tend to be associated with fault zones and cavities adjacent to mineral veins.
We recommend using a dowser before drilling to reduce the risk of a dry hole