Depends on where it is. It is common with clay-based soils to have standing water in the yard after a rain. It does not necessarily mean you will need flood insurance. Was the Flood Zone answered? Plain, way, or No are the options. Plain or way mean you will need flood insurance, your lender will tell you how much.
Otherwise, standing water can be cured by a french drain to drain the water. Other landscaping or concrete options can be discussed with a landscaper and the spot could be made into a patio or terraced area that would be really beautiful and an asset when you get ready to sell the house. Bottom line don't let that scare you at all.