In person, eyeball to eyeball. Part of this process is a risk assesment. You're not likely to get every question answered.
Experts differ on the severity and probability of electric and water system failures.
Some say there is little risk of prolonged and damaging failures. Others say there is high risk. We can probably safely say that no one knows for certain. It is likely that the degree and length of the failures will be determined by geographical area, predominant source of fuel for power generation, size of the utility, size and nature of the customer base, and the stability of telecommunications and transportation systems. If your business is highly dependent on either electric power or water supplies for the preservation of product inventory, it is prudent to plan for a failure of several days duration for both electric and water.