To clarify your concern, are you concerned about a flood event reaching the house; or about the soil suitability for a foundation close to wet ground?
Van Zant is in the Trinity River basin, I believe. If you have been in Texas long you will understand what that means. The Trinity gets "Big Water" at least every 50 years and leaves its banks. How close are you to a creek or stream? Flood Plains are hard to identify in East Texas, as they can be miles across; and one can be in low water plain without noticing.
The good news is that pond is a cut stock tank, or artificial pond. Unless you are in a low lying flood area, you have little to worry about if the pond has a spillway properly installed. You can download the FEMA flood map for the county here and see where the property is compared to known and projected flood risks.
As far as foundational concerns you can download the County's soil survey here Soil Survey
. Look for issues with expansive soil in the area. In areas with expansive soils, the ground will shrink in a drought, and swell in times of high precipitation. This plays hell with a foundation. The pond may actually help keep the soil neutrally hydrated during extreme weather periods.
My biggest concern with a house that close to a pond in East Texas would be mosquitos. Keep that pond stocked with fish and wildlife to combat the bugs. Otherwise they will drive you indoors for large parts of the year.