I’m in the process of buying a vacant lot acreage from the County and realized it’s in a 100 year flood plain. Is this a big issue, or would potential developers just need to mitigate during the construction process? (elevating the properties, etc.)
It is a big issue, but not necessarily a deal breaker. Do some due diligence with your local zoning officer to understand how much of the property is buildable and what the elevation requirement is.
Your end buyer will have flood insurance to purchase which will impact your selling price. Check into what flood insurance will cost for what you plan to build to factor it into your proforma. You won't pay much of it, but your buyer will be considering it when figuring out how much they can afford.
I am buying 2 in a flood plain in NJ. The FEMA elevation requirement is 11 feet above sea level. NJ adds 3 more feet. The municipality adds another 3 feet. That puts us at 17 feet, but the ground is 14 feet above sea level. We only need to elevate 3 feet. Other properties in the area almost need an elevator to get to the front door. I wouldn't like that at all. You need to consider the impact of the elevation on your end product.
Have you been following the weather last decade, 100-year floods happen every year. Check out the past history very carefully for that area.