Legal Question in Real Estate Law in California

Any licensed and regulated utility qualifies to use a "utility" easement. If the easement is more specific, e.g., as to the type of utility, then it may be a different story. However, even if they were not acting within their rights, what are your damages? If they did not restore the property to reasonably similar condition to before they started digging, you would have a damages claim whether they have an easement or not. If they assert an ongoing right to do this and they do not have easement rights you could get a declaratory relief judgment and an injunction. How much do you want to spend to do that? It will easily cost tens of thousands of dollars.

It depends on the kind of easement you have on your property. What does it specify with regard to utility access, and does it define the term? This will determine whether or not you have legal recourse.