This is actually Chicago, Hegewisch is a neighborhood in the city.
Insurance is going to be tied to value and what the coverage is. If the house is in a flood plain, the coverage will be based on the incidence of flooding there, whether the property has flooded before (it's insurance history) and wht you are protecting against.
You will need to contact a carrier that provides insurance in the area, I would suggest looking for a local broker there to start. You will need to provide an address, value and what you know of the property's history of flooding to get a solid quote.
If you use a Realtor for the purchase, and they use the standard contract form (multi board contract 5.0 or 5.1), you will be able to put the property und contract and shop for the insurance knowing if it is not nsurable, or the cost is too high, you can void the purchase.