Houses and other types of real property may have defects, ranging from leaking roofs to insecure foundations. It is prudent, before buying, to investigate the property. It is virtually always a good idea to hire a home inspector.
Home inspectors are regulated by the State. California Business & Professions Code 7195 and so on. The law does not require home inspectors to be licensed. Unless a home inspector is also an engineer, he or she is not qualified to give you an opinion on the structural stability of the house. Likewise unless the home inspector is also a licensed contractor, he or she is not qualified to give you an opinion on such technical construction issues as whether the electrical wiring is sound. If you have concerns about these issues, you should hire a competent specialist to evaluate it for you.
Much of California is subject to earthquakes, floods, mudslides and wildfires. Many homes are built in potentially dangerous areas, such as steep hillsides. In areas with these risks, it is wise to hire a civil engineer, geologist or a soils expert to evaluate the stability of the structure and the land.