What is the minimum height requirement for the lowest floor of a new house in a Zone AO marked with a depth of 3 feet?

In your situation, the minimum height requirement for the lowest floor of a new house located in a Zone AO marked with a depth of 3 feet is defined by regulations that ensure new construction is adequately elevated to protect against flood risk. Zone AO represents areas that are subject to inundation by the 1-percent-annual-chance flood event, where the depth of flooding is determined.

For Zone AO, the regulations specify that the lowest floor must be elevated to a certain height above the highest adjacent grade. Specifically, it must be at least as high as the depth of the designated flooding. In this case, since the Zone AO has a depth of 3 feet, the lowest floor must be elevated at least 3 feet above the highest adjacent grade.

This requirement is in place to reduce the risk of damage from floodwaters and to ensure that the structure is safe in flood conditions. Therefore, selecting the option that indicates the lowest floor must be at least 3 feet above the highest adjacent grade aligns with the National Flood Insurance Program (NFIP) standards regarding construction in flood-prone areas.