The FEMA Flood maps are revised periodically - what may not have been a "high risk" area as determined by FEMA a few years ago could well be one now.
That can explain why a lender who did not require flood insurance even just a few years ago, may have that requirement now (or vice versa) on the same property.
If you look at the survey you received when you settled on your house, if the flood elevation was performed, the survey would state what flood zone you are in (AE, A, etc followed by a number). This is your flood zone designation. But you'll still need the elevation certificate to go further.
When I was trying to buy gap insurance to cover only the perceived gap in coverage provided by my condo association and what the bank thought it should be (????) I learned that the insurance broker could not even quote this coverage without having the information on the elevation certificate.
Here's a link to the FEMA Elevation Certificate - this form needs to be filled out by a licensed surveyor. You'll be able to see the level of detail involved that is required to determine the BFE for your home. Only when you have the BFE for your home can you determine if flood insurance should be purchased regardless of any lender's requirements.
http://www.fema.gov/library/viewRecord.do?id=1383
You really need to have this done to make any kind of evaluation.
Incidently, the flood insurance program (like any other government entity) is often under attack. You may find this article interesting from the Feb 22 edition of Coastal Contractor. There is legislation being proposed to eliminate the Fed. flood insurance program. BTW, it states that all flood insurance is subsidized through this program, and suggests that there is no source for flood insurance outside of this program.
http://www.coastalcontractor.net/article/434.html
One other thing to keep in mind, there is a waiting period for flood insurance, in that if you buy it today, there is a 30-day waiting period for coverage. So if the hurricane is coming next week, you can't buy insurance now and expect to be covered next week. This period is waived when buying a new house.