Is VLF-EM scanning for fractures a valid way to find groundwater for a well?
VLF-EM is a perfectly valid technique for helping an expert decide where best to locate wells in geological environments where water is largely flowing in fractures. Typically it is a useful technique in fractured bedrock where a successful water well needs to intercept connected fractures or fissures. In other geologies, for instance porous sandstones, it would be much less useful. Drilling for water in fractured terrains is always a slightly risky proposition; geophysical techniques help site wells to intercept fractures but they can't guarantee yields, which will depend on how large the fractures are and how interconnected they are. A reputable contractor should be prepared to provide references from satisfied clients and that is a good starting point.