Pictures of elected officials.
Cover Photos (Clockwise from top left): U.S. Senator Debbie Stabenow of Michigan announced federal funding for flood mitigation in Detroit, including new water-absorbing landscape installations on August 6, 2015. Photo by the office of Senator Stabenow; Valley View, Ohio Mayor Jerry Piasecki was interviewed by ASFPM in May 2019 to talk about flood mitigation in his community. Photo by ASFPM; Lt. Col. Anthony Mitchell, commander for the U.S. Army Corps of Engineers, Nashville District; Nashville Mayor Karl Dean; and Metro Water Services Director Scott Potter announced the development of a unified flood preparedness program during a news conference at the Metro Courthouse on Tuesday, Feb. 15, 2011. Photo by Mark Rankin/USACE; Roseville, California Mayor John Allard was interviewed by ASFPM in March 2019 to talk about flood mitigation in his community. Photo by ASFPM.

Note: These website pages contain the official published version of Understanding and Managing Flood Risk: A Guide for Elected Officials. Printable .pdf versions are available at the following links: Volume I: The Essentials, Volume II: Moving Beyond the Essentials, Volume III: Success Stories. Please note that this website may be edited in the future with additional updated content but there is no plan to update the .pdf versions produced in February 2020.

Section D. Why do Communities Manage Floodplains?

Communities manage floodplains because promoting public health, safety and general welfare, and providing some degree of property protection, is an exercise of the police powers conferred by state constitutions and statutes. Floods are the leading cause of natural disaster losses in the United States. Floods affect every region of the country. A majority of events declared disasters by the President include flooding as a primary or secondary cause of damage. But the problem is greater than suggested by even the biggest flood disasters; more than half of damaging flood events do not qualify for federal assistance.

Annual Flood Losses 1990-2018 chart.
CEMHS, 2019. Spatial Hazard Events and Losses Database for the United States, Version 18.1. [Online Database]. Phoenix, AZ: Center for Emergency Management and Homeland Security, Arizona State University. www.sheldus.org

Since 1990 flood losses have averaged nearly $16 billion per year and per person annual costs have increased fourfold. Total flood losses by decade have jumped from approximately $142 billion in the 1990s to nearly $210 billion in the 2000s and through 2018 have already reached roughly $141 billion.

Top 5 Costliest US Hurricanes on record.The top five costliest U.S. hurricanes on record have occurred in the past two decades – Hurricanes Katrina (2005), Sandy (2012), Harvey, Maria and Irma (2017) causing more than $497 billion in direct losses with a significant portion being flood-related losses. What is known is that major flooding events of all sizes inflict huge tolls on individuals, businesses and communities.

The costs and impacts of flooding go far beyond the direct losses to buildings. When flood events are declared major disasters by the President, recovery costs for certain recipients and some categories of damage may be eligible for federal disaster assistance, but those funds are never enough to pay for full recovery. Some impacts are short term, while others may be felt for months or years, hampering recovery and possibly impairing economic growth:

  • Communities may not be able to provide utility service if water and wastewater treatment plants and distribution systems are damaged. Flooded public buildings, roads and bridges, schools and recreational facilities impair public services and require immediate, sometimes expensive, repairs. Paying for recovery typically requires diverting capital improvement funds from long-planned projects. Many communities face removal of massive quantities of debris in an era of dwindling landfill space.
  • Families and individuals may lose jobs or have reduced wages, face significant costs for repairing uninsured damage to buildings and vehicles, or incur additional housing costs as they pay for a place to stay while their homes are repaired. As a result, many families and individuals cope with long-term economic, health and mental health issues.
  • Businesses may have to scale back or shut down when suppliers are flooded, roads are closed, water and sewer services are impaired, and when employees are coping with loss of housing. Businesses may experience these impacts even if they are not directly affected by an event. Many small businesses never recover after sustaining major flood damage.

Flood Losses at the Local Level

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Local flooding can have a much greater impact than is commonly thought. Consider that for every federally declared flood disaster, numerous other floods never get declared – and little to no federal assistance is available. Studies show that communities experiencing a major flood take years, if not decades, to recover. For example, 50 percent of small businesses never reopen after a major flood, and those that do fail at a higher rate within a few years.

For many communities that have not experienced a flood in recent years, it is only a matter of time until a major event occurs. When a flood occurs in a developed area, any and all of the following impacts on communities and their residents and businesses can be expected:

  • Decreased revenue due to loss of income, sales, tourism and property taxes
  • Costs incurred due to post-flood clean up and repair of buildings and infrastructure
  • Loss of jobs due to businesses closing or cutting back on operating hours
  • Risk of injury or loss of life, including first responders rescuing those who did not evacuate or are stranded
  • Mental health and family impacts, including increased occurrence of suicides and divorce
  • Loss of historical or unique artifacts
  • Loss of programs or services that are cut to pay for flood recovery
  • Deterioration of homes and neighborhoods as floods recur

From ASFPM NAI How-to Guide for Planning


21. What is the National Flood Insurance Program?

The National Flood Insurance Program (NFIP) is a voluntary federal program that enables property owners in participating communities to purchase insurance against flood losses in exchange for those communities adopting and enforcing regulations that reduce future flood damage. The NFIP provides the maps and regulatory basis for local floodplain management programs.

  • More than 22,300 local jurisdictions participate in the NFIP, while just over 2,000 communities identified as flood-prone elect not to participate.
  • Nearly 5.1 million flood insurance policies are in force, providing financial protection for homeowners, business owners, tenants, nonprofit organizations and governments.
  • More than 1.8 million claims have been paid, totaling more than $68 billion.

Well into the mid-20th century, much of the United States relied on increasingly costly disaster relief to aid flood victims and large public expenditures to pay for structural flood control measures such as dams and levees. Despite billions of dollars invested in such projects, losses of life and property and the amount of assistance paid after disasters continued to increase. During the same period, the private insurance industry found it uneconomical to provide private insurance coverage for flood damage. Seeking a better solution, the U.S. Congress authorized the National Flood Insurance Program in 1968, noting three primary goals:

  • To reduce the emphasis on structural flood control measures and balance them with nonstructural community- and state-led floodplain management measures (e.g., elevating buildings above damaging floods)
  • To reduce federal disaster costs by shifting the burden from general taxpayers to floodplain occupants
  • To provide flood insurance coverage not available on the private market

By providing assistance to flood victims in the form of insurance, and by stimulating state and local floodplain management to constrict the development of flood-prone land, the NFIP creates incentives for communities to help themselves and their citizens. These incentives correspond with the overall goal of responsible government decision making in flood hazard areas stated by the Federal Task Force on Flood Control in 1965: "those who occupy the floodplain should be responsible for the results of their own actions." This conceptual basis of floodplain management through insurance and development regulations shifts some of the costs of developing flood hazard areas to private and public landowners.


22. How do communities use regulations to manage floodplains?

Fundamentally, regulating and managing floodplains has two beneficial components: (1) identifying the risk of flooding by producing floodplain maps and (2) applying regulatory criteria to development in identified flood-prone areas to avoid or minimize flood damage. States and communities regulate floodplains to achieve other objectives, including protection of environmental features, providing public open space, greenways and recreational opportunities, and protection of natural and beneficial floodplain functions. Accurate maps that identify flood-prone areas allow communities to incorporate flood risk management into comprehensive plans, land development codes and local mitigation plans to reflect their long-term goals relating to increased resiliency following floods.

Top Five NFIP Community Responsibilities

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  1. Adopt and enforce floodplain management regulations that require permits for all development in mapped floodplains.
  2. Designate a floodplain manager.
  3. Require new and substantially improved buildings to be elevated above the base flood elevation (also called the 100-year flood elevation).
  4. Conduct field inspections of the mapped floodplain and inspection of permitted development before closing permits or issuing certificates of occupancy.
  5. Maintain permit records, including elevation documentation and variance requests.

As community officials work to plan and make decisions to make their communities more resilient, the maps provide value beyond just determining where the regulations apply. NFIP regulation (44 CFR Section 60.22(c)) identifies additional planning and zoning considerations that communities should adopt to guide development in ways that exceed NFIP minimum standards, including:

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States must also meet requirements.

The NFIP considers states to be communities and expects them to establish and enforce floodplain management requirements for state owned properties and development in mapped floodplains. States can meet NFIP floodplain management requirements through governor’s executive orders, legislation or regulation.

  • Diverting development to areas outside the floodplain using density limits, conservation zoning and transfer of development rights
  • Disclosing flood risk to property owners, developers and buyers
  • Acknowledging that floodplain development may increase flood risk for existing flood-prone development
  • Improving local drainage to control runoff from roofs and paved areas that increase the probability of flooding on other properties
  • Requiring buildings to be elevated using pilings or columns, rather than fill, to maintain the storage capacity of the floodplain and to minimize environmental impacts
  • Requiring evacuation plans for manufactured home parks and subdivisions and other vulnerable areas

No Adverse Impact (NAI)

NAI Logo.

No Adverse Impact is an approach to floodplain management that ensures the action of any community or property owner, public or private, does not adversely impact the property and rights of others. Developed by ASFPM, the fundamental premise of NAI is consistent with the ancient legal principle, "Sic utere tuo ut alienum non laedas," which means "so use your own property that you do not injure another’s property." Question 42 of this Guide includes more details on the NAI approach to floodplain management.


23. Can communities face consequences for not enforcing, or not adopting, floodplain management regulations?

State constitutions or statutes confer upon local governments the authority (often called "police powers") to adopt regulations designed to promote public health, safety and general welfare of the citizenry. Property protection is a component of promoting public safety and general welfare.

Communities can reduce their liability for damage by responsibly regulating development and use of community assets, including infrastructure, land or buildings. Floodplain management has come a long way in the last 50 years. Progress is reflected in the knowledge and understanding of flood hazards, as well as which actions society considers "reasonable" to prevent or limit flood damage. In terms of liability, communities have a responsibility to act reasonably to:

  • Protect property owners from known hazards
  • Prevent property owners from taking actions that would increase flood damage on others
  • Enforce adopted regulations uniformly
  • Protect the public from the community's own actions, which may increase future risk

What might happen if a community ignores these responsibilities and does nothing about known flood hazards? In recent years, increasingly broad rules of liability can put landowners and communities at risk if their actions (or inactions) contribute to another's damage as a result of flooding. Also, the "act of god" explanation for large floods that used to be a successful defense against flood losses in common lawsuits may only be useful for very large and unforeseeable events. Given our modern understanding of the science of flooding, improvement in weather forecasting, and the increasing frequency of severe flood events, it may no longer be acceptable to claim flooding was unexpected.

Where can we find information about floodplain management, flooding and liability?

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ASFPM makes available several papers about liability and other legal matters related to floodplain management. Some papers supported by the association speak broadly to reducing government liability, protection of property rights before floods, public liability for flood hazard mitigation, professional liability for construction in flood hazard areas, and liability for failure of water control structures. The website also includes papers about a small number of specific cases decided in recent years.

Access at www.floods.org, Publications and Policy Papers and Legal Papers.

Simply put, failure to act to protect public health and safety could be considered by courts to be negligence on the part of a community. Poor enforcement and willful disregard for adopted regulations may be considered a failure to act reasonably. Modern flood warning systems and robust natural hazard modeling techniques mean floods are more foreseeable than in the past, which means communities have more tools to manage flood hazards and limit damage.

What if my community has chosen not to participate in the NFIP?

Chat and question cartoon bubbles.

Out of nearly 25,000 communities, only about 2,000 identified as flood-prone elect not to join and nearly 200 are suspended. If your community is one of those, you’re probably not regulating flood hazards, which could put people and property at risk. Also, your citizens won’t be able to purchase NFIP policies, which could limit access to most mortgages. Federal grants and loans for development in special flood hazard areas (SFHAs) won’t be available, and some types of federal disaster assistance are limited, putting the burden for recovery entirely on local resources.

Contact your NFIP state coordinator to learn more (see Question 41 for sources for more help).


24. Do floodplain management regulations create unreasonable barriers to development?

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What should I look for to determine if my community’s regulations protect against "takings" challenges?

Evaluate whether the regulations:

  • Utilize a performance standard approach (specifies criteria for development rather than prohibiting development)
  • Grant variances in certain limited circumstances
  • Are supported by scientifically sound hazard maps
  • Are adopted and administered in conformance with statutory procedures (e.g., notice and hearing)
  • Are reasonable and fair in administration and enforcement
  • Document threats to public health and safety, and the potential for nuisances

From Flood Risk in the Courts: Reducing Government Liability While Encouraging Government Responsibility

Floodplain management regulations help ensure that we're building and recovering safer, stronger and smarter. If we know an area is mapped as having the potential to flood, and if we know people could be in danger and buildings could be damaged, it makes sense – and we have a responsibility – to take reasonable protective steps as communities develop and redevelop. In the same way that building codes mandate design features that protect buildings and people from fire, floodplain management regulations provide degrees of protection from flooding.

However, there are many factors that drive a desire for development in communities. For example, elected officials may hear versions of: "If we restrict what a property owner can build in the floodplain, aren't we taking away the owner's right to develop land as he sees fit?" or "How can we meet our needs for growth if we're not developing these highly desirable (yet flood-prone) areas near the water?" It is important for you to remember that responsibly regulating development in known hazard areas can help avoid liability and lawsuits that challenge the constitutionality of land use regulations. Also remember there are significant benefits to safeguarding your community's residents, businesses, and economy.

As you make decisions around damage reduction measures, be mindful to choose options that reflect the degree of flood risk and characteristics of flooding in your community, as well as types of potential uses of the floodplain. For example, prohibiting hazardous materials facilities in areas prone to flash flooding may be more reasonable than prohibiting a baseball field and bleachers in an area prone to shallow tidal flooding.

Flood risk may vary from community to community.

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Different characteristics of flooding cannot be determined simply by looking at flood maps. Flood risk varies depending on depth of flooding, how rapidly flooding occurs (flash floods), how fast floodwater moves, how long flooding lasts, salinity of floodwaters, the presence of waves and debris, and whether soils are vulnerable to erosion.

The defining characteristics of the NFIP minimum floodplain management requirements are described in Section G, and Section H describes a number of effective ways communities have strengthened local programs.

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