There are very few flood zones within the Freeport (just the obvious ones near the drainage ditches and creeks). Most housing is high up in the hills...
Within the areas of Olongapo and Barrio Barretto, I would expect flooding depending on how close you are to runoff areas. I doubt that you will find any flood zone maps. Subic town (just west and north of Barretto) was flooded bad too.