• Home & Living

Floodplain Construction Regulations



In most communities throughout the United States, construction in floodplains is governed by combinations of Federal, State, and local regulations. At the Federal level, FEMA administers the NFIP. Congress created the NFIP in 1968 when it passed the Act (NFIA). The NFIP is a voluntary program for communities. Its goal is to reduce the loss of life and the damage caused by flooding, to help the victims of floods, and to lower the costs of borne by the taxpayer. Communities participate in the NFIP by:

  • guiding future development away from flood hazard areas,
  • requiring that new buildings, substantially improved existing buildings, and repair of substantially damaged existing buildings in the SFHA be constructed in compliance with management ordinances and laws intended to reduce flood damage,
  • providing floodplain residents with after floods, and
  • transferring the cost of flood losses from the taxpayer to the owners of flood-prone buildings by requiring the purchase of flood insurance for buildings in the SFHA.

Under the NFIP, an improvement of a building (such as reconstruction, rehabilitation, or an addition) is considered a substantial improvement if its cost equals or exceeds 50 percent of the market value of the building before the start of construction of the improvement.

Similarly, damage to a building, regardless of the cause, is considered substantial damage if the cost of restoring the building to its before-damage condition would equal or exceed 50 percent of the structure before the damage occurred. Consult your local officials about determining the value of your home.

For more information, consult your local officials or refer to FEMA 213, Answers to Questions About Substantially Damaged Buildings.

The NFIP operates through a partnership between the , the States, and individual communities such as counties and incorporated cities, towns, and villages.

A participating community adopts and enforces a floodplain management ordinance or law to regulate development within that floodplain, including new construction, substantial improvement of existing buildings, and repair of substantially damaged buildings. In return, federally backed flood insurance is made available to property owners and renters through the community.

A participating community’s floodplain management ordinance or law must, at a minimum, meet the requirements of the NFIP regulations, but each community is free to establish additional or more stringent requirements to provide additional protection. For example, the regulatory floodplain defined by a community must include the entire SFHA, but it may also include other flood hazard areas within the community. Additionally, some States require communities to adopt and enforce floodplain management requirements that exceed the minimum requirements of the NFIP.

These points are particularly important because of their potential effect on your retrofitting project. In this guide, you will find many references to requirements included within your community’s floodplain management ordinance or law. These are the minimum requirements that all communities must adopt and enforce in their floodplain management ordinances or laws to be compliant with the NFIP regulations. Remember that you must comply with your community’s requirements, which may be more stringent.

Usually, communities enforce other requirements that affect construction, both inside and outside of the regulatory floodplain. These requirements include those associated with building codes and land use regulations, such as zoning and subdivision ordinances.