This is one of the first things I check on all properties that I invest - before I even make an offer. And many states only require accurate disclosure for residential, not commercial properties (not sure which Alabama is here, but sounds like no disclosure for anything required).
I have had some family members purchase a residential property in Colorado where the Seller's disclosure lied about some material facts (I think they stated the plumbing was in good working order, but they had covered up a known leak that caused a lot of damage). This eventually went bad and took about 20,000 to address - there was a legal situation and my family members received full compensation for the Seller's coverup.
So irrespective of that story, your options are to:
- Keep the home and see how you can insure the flood risk (which will cost more than something in the 500 year or no flood plain) and then expect that over the years you will have to budget for a remodel due to a flood. Anyone buying the property from you at a future date will also have to get a Flood Insurance policy from a bank, and this will be uncovered at that time - which may or may not kill the re-sale.
- You may have an option legally to undo the deal due to the Seller's inaccurate disclosure combined with your contract clause - I don't know the strength of your case based on your State's case law and statutes of limitation, so you will need to check with a licensed attorney in your state with this experience.
- Get a topographic survey to confirm the extent of the flood plain on your property. There are times where flood plains are not accurate on the FEMA maps and this survey could uncover that - you can request the FEMA maps be updates using a LOMR or LOMA (I forget which it's called now) and then this become a non-issue. The survey will run about $750 and updating the FEMA maps is usually a couple thousand. This would save you money in the long run as it would reduce your insurance costs and then restore its ability for banks to loan without the flood insurance.
- Raise the home off the ground so that the floor is 12 inches (or more) above the base flood elevation. If it's a home already on pier and beams this may not be a huge job...but if it's slab on grade probably not an option.
- Do nothing and pray it never floods (don't do this please).
I am developing a property in a floodway, 100 year, and 500 year floodplain and am having to spend a lot more on engineering and site preparation to get plans approved with the City and de-risk the site's flood risk. I know it's not fun.
I wish you the best of luck getting this resolved.