Keep in mind that the position of the home on the lot will determine to what extent a home is or is not in a flood zone. The mortgage company may or may not require flood insurance....if your neighbors don't have a mortgage, they may not have flood insurance, either.
Do you want to know if your neighbors have flood insurance or if they qualify for it?
I am at a loss as to why you want to know... but go to your local town hall and see whether flood insurance is required in your area. You can get flood insurance even though you are not in a flood area and this will cover water damage in your basement etc as indicated in the answer #1 below- but the coverage is very limited and it is well worth speaking with an insurance specialist.