Guides
Elevating a home and other flood mitigation
How elevation, flood openings, raised equipment, floodproofing and buyouts work, what each does to flood insurance premiums, and where the money comes from.
Raising the lowest floor of a house above the expected flood level is the one change that reliably cuts both flood damage and, usually, the cost of National Flood Insurance Program (NFIP) coverage. Smaller steps also count: flood openings in a crawlspace wall and furnaces or water heaters moved above the flood line can earn a mitigation discount. Dry floodproofing a house, by contrast, does nothing for your premium, and FEMA advises that only non-residential buildings should consider it.
This guide covers what each measure does, what the rules require, how it reaches your insurance bill, and the funding that exists. It describes NFIP flood insurance. Your homeowners policy excludes flood, so none of this changes that policy's coverage; see does homeowners insurance cover flooding?.
The options at a glance
FEMA's Rebuilding Safer & Stronger After a Flood guide (December 2022) lays out the choices. The insurance effects below come from that guide and from FEMA's Risk Rating 2.0 materials.
| Measure | What it is | Effect on premium | Main limits |
|---|---|---|---|
| Elevation | Lift the house, or build a new raised floor, so the lowest floor is at or above the base flood elevation | Usually the largest reduction, because first-floor height is a rating input | Cost, engineering, permits; some communities require extra height ("freeboard") |
| Flood openings | Vents in the walls of a crawlspace or enclosure that let water in and out | Qualifies for a mitigation discount | Must meet NFIP size and height rules |
| Raised utilities | Move the furnace, water heater, panel and similar equipment above the flood level | Qualifies for a mitigation discount when machinery is elevated | Ask your agent which equipment and heights FEMA's rating accepts |
| Wet floodproofing | Let water enter non-living space (garage, crawlspace, basement) and limit the damage | The openings and raised equipment it involves earn the discounts above | Not a substitute for elevation on a substantially damaged house |
| Dry floodproofing | Seal the building so water stays out | FEMA says it will not reduce premiums for residential buildings | Meant for non-residential buildings; needs shields set up before the water arrives |
| Relocation | Move the house to higher ground | Can remove the exposure | Typically the most expensive option |
| Demolition, rebuild or buyout | Remove the building; rebuild to code or sell to a government program | Ends the exposure or resets it to new-construction standards | Buyouts depend on a government program, and funds are limited |
Elevation
FEMA's description of the process: the building is separated from its foundation, raised on hydraulic jacks, held on temporary supports while a new or extended foundation is built beneath it, and set back down. That works well for homes on basements, crawlspaces and open foundations. Slab-on-grade homes can be lifted with the slab and a new foundation built under it, or detached from the slab and set on a new raised floor.
The target is the lowest floor at or above the base flood elevation, and some communities require more. "Check with your state and community, as some regulations require you build a specific number of feet above the BFE," FEMA says in the guide, using the term freeboard. Ask your local floodplain administrator what applies before you design anything.
Two cautions. Elevation lowers flood risk but does not remove it, and FEMA's guide asks owners to weigh other hazards, such as wind, before choosing it. And the work has to be done to code and verified: for elevation to count as a mitigation measure for insurance, a mitigation expert must verify it and the result must meet the definition of an elevated building. An Elevation Certificate from a licensed surveyor after the work documents the new height for your insurer and your community.
Flood openings and raised equipment
Crawlspaces and enclosures below an elevated house fill with floodwater and, if sealed, can be crushed by the pressure difference. NFIP Technical Bulletin 1 (March 2020) sets the baseline for the openings: at least two openings on different walls of each enclosed area, a total net open area of at least one square inch per square foot of enclosed space, and the bottom of each opening no more than one foot above the adjacent grade. Screens and louvers are acceptable only if floodwater can pass through automatically. A door or panel that someone has to open before the water rises does not count. Engineered openings are allowed when a design professional certifies they equalize pressure.
Say your crawlspace is 1,000 square feet. The openings must total at least 1,000 square inches of net open area. An opening that is 128 square inches (FEMA's example, an 8-by-16 block void) means roughly eight openings, spread across at least two walls. A vent placed high on the wall will not satisfy the one-foot rule.
FEMA's Risk Rating 2.0 pricing gives a discount when openings are installed, when machinery and equipment are elevated, or both. Moving a furnace, water heater and electrical panel out of a low basement or crawlspace also cuts the damage that does occur. See Risk Rating 2.0: how NFIP prices flood insurance now for how the discount enters the bill, and what flood insurance covers in a basement for what the policy pays for items below the lowest floor.
Why dry floodproofing is different
Sealing walls, shielding doors and installing backflow valves can work for a commercial building. For a house, FEMA's guide says only non-residential properties in good condition should consider dry floodproofing, that it cannot be used to bring a substantially damaged or improved building into compliance unless the community has a floodproofing exception, and that dry floodproofing residential buildings "will not reduce flood insurance premiums." The system also depends on someone being there to install shields before the water comes. Sealing the walls of an existing house adds a hydrostatic load the walls were never designed for.
When the rules force the issue
If a flood or a renovation is large enough, your community may require the house to be elevated whether you wanted to or not. Under FEMA's rules, a building is substantially damaged when the cost to restore it to its before-damage condition equals or exceeds 50% of its market value before the damage, or a lower percentage if the community has adopted one. A substantial improvement is the same test applied to a rehabilitation or addition. Either triggers compliance with floodplain regulations for new construction, and the determination can be cumulative.
That is what increased cost of compliance (ICC) is for. According to FEMA's October 2025 Flood Insurance Manual, ICC coverage pays up to $30,000, subject to eligibility, toward elevation, floodproofing, relocation or demolition. It is paid in addition to your building coverage, but the two together cannot exceed the $250,000 statutory maximum for a single-family home. The steps are in how to file a flood insurance claim. Your homeowners policy's ordinance or law coverage does not respond to flood damage.
Paying for it
Say a hypothetical elevation bid is $90,000. ICC can contribute at most $30,000 if you qualify, so most owners assemble the remainder from several sources:
- Hazard mitigation grants. FEMA's Hazard Mitigation Grant Program is triggered by a presidential disaster declaration, and Flood Mitigation Assistance funds reduce repetitive flood damage to NFIP-insured buildings. In both, states, territories, tribes and local governments apply, not individual homeowners, so the route to a grant runs through your local emergency manager or floodplain administrator. FEMA's FMA page shows a fiscal year 2024 notice of up to $600 million with a deadline of August 6, 2026; its BRIC page shows a funding notice published March 25, 2026 with applications that closed July 23, 2026. Both programs have changed repeatedly, so ask what is open now.
- Buyouts. After a declared disaster, local officials can ask the state for money to buy flooded or substantially damaged properties. FEMA may pay 75% of the buyout cost, the state or local government pays the rest, and the land stays open space. You cannot start one yourself, and funds are limited.
- State and local programs, savings and loans. These vary widely; your state's hazard mitigation office is the starting point.
A sequence that avoids expensive mistakes
- Learn your numbers. Get your zone and base flood elevation from Flood zones and FEMA flood maps explained and your lowest-floor height from an Elevation Certificate.
- Ask your community what is required. Substantial damage thresholds, freeboard and permit rules differ.
- Ask your flood insurance agent what the change is worth. Request the premium as it is now and as it would be with the proposed elevation, openings or raised equipment, then run the numbers in the roof and mitigation upgrade payback calculator.
- Get engineered bids from contractors who lift houses, not just general remodelers, and have each state who verifies the work.
- Document everything: permits, final inspection, photographs of the openings, a new Elevation Certificate.
- Send the paperwork to your insurer and confirm the discount or re-rate on the next bill.
- Update your homeowners policy. A new foundation changes the home's construction, and your agent should know.
Key takeaways
- Elevation is the measure with the largest effect on flood damage and NFIP premiums, because first-floor height is a rating input; it must be to code and verified to count.
- Flood openings (two or more, on different walls, at least one square inch per square foot of enclosed area, within a foot of grade) and elevated equipment earn a mitigation discount.
- FEMA says dry floodproofing a residential building does not lower the premium and is poorly suited to existing homes.
- ICC pays up to $30,000 toward elevation or relocation after substantial damage, within the $250,000 combined cap, and grants go through governments rather than individual applications.
- Ask your insurer to quote the premium before and after the work, and send the new Elevation Certificate once it is done.