Where alleys are not provided, easements for utilities shall be provided in accordance with the provision of this chapter. Such easements shall have minimum widths of 20 feet, and where located along lot lines, one-half of the width shall be taken from each lot. Before determining the location of easements, the plan shall be presented to the local utility liaison committee to encourage recommendations for their proper placing for the installation of all utility services. No structures shall be placed within easements.