Springtime in Northern Virginia can include a lot of rainy days and there are the occassional winters with snow melt. Some areas are more prone to flooding than others -- Old Town Alexandria, Georgetown, and up around the Great Falls Park -- all because of the rising Potomac.
But there are some areas noted on the FEMA maps which are in flood zones. Before getting overly concerned if you are looking at a map, talking with your hazard insurance company, your lender, and me, may calm the concerns.
However, here's a link to FEMA's maps so you can take a look. Click here