Immediately after the determination by the county government that the community in question meets the requirements for a suburban community specified in § 551 of this title, the county government shall notify the county engineer of its determination. Upon receipt of such notice, the county engineer shall promptly review the plans and proposals submitted by the petitioners and the owner or operator of the local water distribution system chosen to install the improvements, and shall notify the county government of his or her approval or disapproval thereof.