I have over 13 years experience in Land & Site Development on top of my Real Estate license.I can tell you with no uncertainty that unless you are an experienced land buyer, you really should be working with a Buyers Agent who could answer this and ALL the other questions you have not even though of yet.
Forget working with the Listing Agent, they do not represent you and only want to sell the land.If you are not already represented, I'd be more than happy to assist you. If you are already working with a Buyers Agent, they should be able to address these questions and all the others that will arise.
Tread Carefully with raw land!!!