Building a New House – Can you build in a flood plain?

Can you build in a flood plain? I am guessing you can, or there would be no houses in Florida.

I started doing the research. How flood plain are we? It looks from the survey as if we are only at the edge of the flood plain. We saw the land in the worst flood we’ve had around here in I don’t know how long and it didn’t flood, really. There are houses lower than ours will be. The cabin we live in now is surrounded by flood plain, but it is on a higher spot, so it is written out of the flood plain on the LOMA map. So, if we raise the land, we won’t be in flood plain any more.

Land Survey - All those stripes are flood zone. — Land Survey – All those stripes are flood zone.

Here is the survey.

The county website says; “Portions of this property are in a flood zone. Please contact the Flood Damage Prevention Local Program. Zone AE 1% (100 Year Floodplain); Zone X Not Shaded (Areas outside of the floodplain)”

So, what does Zone AE mean?

Zone AE means our land has a 1% probability of flooding every year. That means we are considered at high risk of flooding under the National Flood Insurance Program. We would have to buy flood insurance. We might run into trouble getting a permit. We would have to find out what our local floodplain zoning ordinance requirements are. And we would have to find out what it will take to bring the house up above the Base Flood Elevation (BFE) on the maps.

We can get the map changed. If you can prove that your house is above the Base Flood Elevation, you can get the maps changed. There are two ways to do it.

If the land is above flood level already, but the map doesn’t show it, you can get a Letter of Map Amendment (LOMA). You just present documentation to prove it and apply to FEMA. That’s not going to work. We really are below flood level.

But you can get a Letter of Map Amendment (LOMA) and Letter of Map Revision based on Fill (LOMR-F). There are forms on FEMA’s website.

Letter of Map Revision based on Fill (LOMR-F): Landowners or renters who, after obtaining appropriate permits, have brought in fill to elevate their property above the Base Flood Elevation should apply directly to FEMA for a Letter of Map Revision based on Fill.

So, if we can get the permits to elevate our land, we can bring in fill, then get a Letter of Map Revision based on Fill (LOMR-F) and we won’t be under flood plain any more.

Worse comes to worst… How much is flood insurance?

How much is flood insurance?

Zone A1-30, AE
At BFE $376.00
1 Foot above BFE $271.00
1 Foot below BFE $1,061.00

That’s not as bad as I thought. This is totally doable.

Floodplain Development Permit Application

So, we hired the surveyor to do whatever he had to do to complete the permits. Survey. Put in a pins for elevation. Fill out the permits. Submit the permits.

First we have to decide on the size of the development. This is not the size of the house. It includes everything we might change the grade of. So we have to include the yard, any driveways and where we are going to put a barn.

What is a Regulatory Floodway?
“The regulatory floodway is the channel of a stream plus any adjacent floodplain areas that must be kept free of encroachment so that the 1% flood discharge can be conveyed without increasing the base flood elevation more than a specified amount.” So… if I’ve got this right, we can’t raise our land if it is going to make someone else’s land flood. That seems fair.

What is BFE?
It is the Base Flood Elevation at the development site.

Proposed method of elevating the structure: (a) If foundation wall is used – provide a minimum of 2 openings and (b) Total area of openings required (1 sq. inch per sq. foot of enclosed footprint area below BFE).
Foundation wall 2200 ~ 2200 sq. in
27 openings = 4624 sq in.

We had to jump through a few more hoops, get insurance… But the surveyor called with good news. We got the permit!

So… Can you build in a flood plain?
Should you build in a flood plain?

If you are making a decision to build in a flood plain, these posts will give you more information.
These are some of the unexpected things we faced when building in a flood plain.

Altogether, it costs tens of thousands more to build in a flood plain. However, I still love the house location.
And we cut off the piece of land that is not in a flood plain to sell.
It is worth more than the additional cost.

So, would we build in this location again, knowing what we know now? Yes, we probably would.

But if you are deciding whether to build in a flood plain, it may cost WAY more than you expect.

Ways to Redirect Water

Is the location for your tiny house or other building above flood plain? How much above flood plain? Even if the land is above flood level, does that particular area flood anyway?

If you have no other choice, even if the area floods, you might be able redirect the water flow.

Planning and Preparing the Location
Ways to Redirect Water to Keep from Flooding >