A lot grading and drainage plan is required to obtain a building permit from the municipality. Basically, the grading plan shows your property, existing grades, its dimensions, the proposed location of your new house, and how the ground around your house will slope or proposed grades. It should also include drainage swales, fences, and easements. The purpose of this plan is to ensure that the construction of the new building, including the driveway, retaining wall etc., will be built in such a manner as to allow for proper surface drainage and to prevent any negative impacts on adjoining land owners.