The locators that show up when calling Digsafe only locate and mark the utilities owned by the utility companies. This means that if you're digging in your back yard and need your shed or out building's power located, you'll be out of luck.
Where those locators stop marking is called the "demarcation' point. For electric it's the electric meter, for water it's normally your street curb stop, Cable and phone is the cable box and NID box respectively. So if you have these demarcation points out by the street or on a pole and NOT on your house; what's buried to your house or business is your responsibility.
I'm able to locate these privately owned utilities by inducing a specific signal on the metallic conduit so that you aren't digging blind putting not only these utilities at risk but yourself as well.
In the case of plastic/PVC water or well lines I do have the capability, in conjunction with your water company and plumber, to feed a snake through your service out towards the street and inducing a signal on the metallic snake itself.
Similarly, for sewer lines, I have separate metallic sewer rods to feed through your service cleanouts in order to trace and locate your septic/sewer pipes.