May I give an anecdote about being very careful about the hidden value/risk of shelters and other preparations when selling a property.
In Portland, Oregon a person I know purchased a property which after closing was revealed to have a medium sized manhole entry type fallout shelter in the back yard. This person was quite annoyed to have what he considered a dangerous hole and had it filled in by a cement pumper and the doors and frame broken away and sodded over, after documenting the total costs he filed a lawsuit against the seller for reducing his property value by not disclosing the shelter. The buyer was raised in a British Commonwealth country and considered survivalist preps to be an American illness. You can expect many Americans to share this opinion and they may consider you strange or paranoid. So, for some buyers, you might unfortunately see your expensive preparations become liability when selling a property. – David in Israel.