Section 406 Hazard Mitigation in Public Assistance

Section 406 hazard mitigation — "406 mitigation" for short — is additional Public Assistance funding for work that makes a disaster-damaged facility more resilient while it is being repaired. FEMA's Public Assistance Program and Policy Guide (PAPPG) describes it as measures that help avoid repeated damage, reduce the potential for future damage to an eligible facility, and provide long-term solutions to hazards that are growing more frequent and severe. Approved measures become part of the eligible cost of the repair project rather than a separate grant. The Stafford Act, FEMA's regulations and the guide are the sources for this page.

That is the main difference from Section 404 of the Act, which creates the Hazard Mitigation Grant Program: a separate, capped funding stream for cost-effective measures anywhere in the area affected by a major disaster, including facilities the disaster did not touch. An applicant may use both on the same facility, but not for the same work.

What it covers

Section 406 of the Act authorizes federal contributions to repair, restore, reconstruct or replace public and eligible private nonprofit facilities damaged by a major disaster, and FEMA's regulations allow its Regional Administrator to require cost-effective hazard mitigation measures beyond what applicable standards call for, with the cost of required measures eligible. Mitigation, in the guide's usage, is work beyond codes and standards: upgrades needed to meet eligible codes and standards are part of the restoration itself, and where a measure goes further than a code requires, FEMA evaluates only the part above the code as mitigation. The Act separately directs that repair costs be estimated under the latest consensus-based codes that incorporate hazard-resistant design, so code-based resilience and 406 mitigation sit on top of each other.

Two structural limits apply. Mitigation can be included only in permanent work, not in emergency work. And the recipient — the state, territory or Tribal Nation — has to have a current, approved hazard mitigation plan before FEMA funds any permanent work.

What the PAPPG treats as eligible

A measure is eligible when it directly reduces the potential for future damage to the damaged part of the facility, meets the cost-effectiveness criteria below, and complies with federal, state, local, tribal and territorial legal requirements, including environmental and historic preservation law. FEMA also considers whether the measure is technically feasible and effective, and whether it would harm the facility's operation or its surroundings or make the facility vulnerable to another hazard.

Eligible measures are usually performed on the damaged parts themselves, though they may protect other parts as well, and a measure that stands apart from the damaged part is judged by how it protects it. The guide's examples include floodwalls or vegetated swales around a damaged facility, new drainage structures along a damaged road, fire-resistant materials and defensible space, and dry floodproofing of buildings that hold interdependent parts of one system. A measure that protects only undamaged parts is not eligible under Public Assistance, though the applicant may seek Hazard Mitigation Grant Program funding for it. Mitigation measures may address any hazard, not only the one that caused the damage. And if FEMA approves mitigation funding and the work is not done, FEMA deobligates it.

Three ways to show cost-effectiveness

Each measure has to be cost-effective, and FEMA's guide gives three ways to show it; meeting any one is enough. Under the first, the measure's cost stays within a set percentage of the eligible repair cost of the facility it protects, calculated before any insurance reduction. Under the second, the measure is one of those listed in the guide's appendix of cost-effective measures — culvert upgrades, bridge restraints, seismic bracing and elevation of building systems, pipe joint restraints, submersible pumps and generator connections, among others — and its cost stays within a higher limit relative to the repair cost. Under the third, the applicant or the recipient shows cost-effectiveness through a benefit-cost analysis using FEMA's toolkit, which weighs the measure's cost against the damage, loss of function, emergency measures and casualties it is expected to avoid, including impacts from past events that were not federally declared. Where a measure fails the first two tests, FEMA and the applicant work together on the analysis.

406 and 404 side by side

Section 406 mitigation is part of a Public Assistance repair project on a damaged facility and protects its damaged parts; it is funded as part of the project at the Public Assistance cost share, with no separate program cap, and it is added to the project through a hazard mitigation proposal. The Hazard Mitigation Grant Program under Section 404 is a separate program, capped at a percentage of the disaster's total assistance, that funds cost-effective measures anywhere in the affected area, including undamaged facilities and the acquisition or relocation of flood-prone property; a state may apply to administer it. A common pattern is 406 funding for the damaged parts of a facility and the grant program for its undamaged parts.

Proposing mitigation, and how it is funded

An applicant, a recipient or FEMA may propose mitigation for a project, and FEMA's mitigation staff can help identify and develop measures; the engineering and design work needed for a proposal is fundable when it is part of the approved mitigation scope and completed. Timing allows for both directions. Where a facility had to be repaired on an expedited basis, mitigation added to the completed, PA-funded repair can still be eligible, though FEMA does not pay for duplicative work caused by adding mitigation afterwards; and measures carried out after the incident but before the declaration or FEMA's evaluation can be eligible when they are cost-effective and FEMA confirms environmental and historic preservation compliance.

The federal share of Section 406 assistance is at least 75 percent, at the cost share approved for the declaration. The Act allows FEMA to offer a higher share to states and Tribal Nations that invest in resilience, but FEMA announced on June 10, 2025 that the policy it had issued in September 2024 to implement that provision no longer applies, including to disasters declared while it was in force, so no increase is available under it. The cost-effectiveness percentages are worked out on repair costs before insurance reductions, and mitigation can be eligible even where insurance covers the whole repair, provided the project as a whole meets the minimum project size. Capped projects have rules of their own: an improved project that includes mitigation loses the mitigation funding if the work is not done or the facility is replaced or relocated, an alternate project leaves mitigation out of its cap, and under the Section 428 alternative procedures mitigation is carried as a separate fixed amount that FEMA reduces if the work is not completed.