Wet Land

I've looked over many pieces of earth for sale, but none attract me as much as the lot I posted about previously... that is until I found this wetlands map on the town planning & zoning website which doesn't make the lot look so pretty...

Now, I walked the land with the Realtor, and it only really feels like wetland in a few small patches toward the bottom of the slope, and the lot has been approved for building and septic. The Realtor says this map is old and that wetlands change, and suggests making an offer contingent on the town's approval of the plan.

Even if the build is legal, my question is whether it is wise to build on a lot where water is drawn to, especially when I am very interested in a partially underground structure.

Is there a way to circumvent the water problem? I've got some investigating to do, including a trip to speak with the town Planning and Zoning folks.