There is flood zone information available on the internet, and the current owners should know whether they needed flood insurance in their area when they bought the property.
Work with an experienced local Realtor to work on your behalf and in your interest only as YOUR buyers agent, he or she will be able to answer all those questions or find out for you from village hall and other.
Do not do this on your own.
By the way the lender will double check on flood zoning, they want to make sure before lending money that the property is sufficiently insured.
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