Can I build in a floodplain?

In the county and city floodplain permit rules cited below, a mapped flood zone is handled with a permit rather than a prohibition. A house, a garage or a gravel drive there is development that goes through the floodplain permit, and a new home's floor height is checked against the flood elevation where one is set.

The federal flood insurance rules call the regulated ground the area of special flood hazard: land in the flood plain with a 1 percent or greater chance of flooding in any given year. What counts as work inside it is broad. The same rules define development as any man-made change to improved or unimproved real estate, and the list runs past buildings to filling, grading, paving, excavation and the storage of equipment or materials. Carroll County's floodplain permit application uses that same definition, so a load of fill or a graveled pad counts as development before a single wall is framed. The word itself, and the terms around it, are set out under floodplain in the glossary.

Each locality runs the permit. Carroll County's application covers any development in a Special Flood Hazard Area shown on the effective FEMA map. In Wythe County the county office that administers the floodplain ordinance issues floodplain development permits, and Pulaski County, which participates in the National Flood Insurance Program, issues floodplain permits from a county office as well. Inside Galax the Galax Building Official handles floodplain permits, and what the Chestnut Creek floodplain means for a city lot is covered on the Galax VA real estate page.

Virginia's flood statute defines flood plain management regulations to include zoning ordinances, subdivision regulations, the building code, health regulations and special purpose ordinances such as flood plain, grading or erosion control ordinances. The Department of Conservation and Recreation coordinates flood protection programs statewide and assists localities with flood plain management.

Once the parcel's zone is known, the permit file has four parts, and they are the useful part to know before a contract is signed.

The floodplain rules also reach an existing house when the work is large enough: a substantial improvement is one costing 50 percent or more of the structure's market value before the improvement starts. Low ground near water can also hold wetlands, and the permits behind filling or draining them are covered in wetlands and what they limit. The foundation design that meets the elevation is work for a licensed design professional and the building official, not a line on a listing.

A mapped zone rarely settles whether a homesite works. It adds three questions to the ones every lot answers, and each has a different office behind it.

• The map. Which zone, which panel, and whether any part of the pad falls in the floodway. The county or city floodplain administrator confirms it for the parcel.
• The loan. A federal flood insurance requirement applies when a regulated lender makes a loan secured by improved real estate or a mobile home in a mapped flood hazard area, and the statute lists exceptions. The lender and an insurer answer for a specific loan and its cost.
• The permits in order. Carroll County's floodplain development permit waits on every other necessary federal, state or local permit, so how it lines up with the building permit is a question to settle with the county early.

The map line is not the flood line on the ground, either. Whether frontage on the New River in particular floods is taken up in does New River frontage flood, and the flood zone is only one pass over a parcel: access, soil, slope and the rest of the list are in what makes a lot buildable.