If the local agency acquires, constructs, or improves a sewer system pursuant to this chapter, it may declare that the further maintenance or use of cesspools or other local means of sewage disposal constitutes a public nuisance. If the buildings are within a reasonable distance, but not more than two hundred feet, from connection with the sewer system, the local agency may require all buildings inhabited or used by human beings and in which any sewage is produced to be connected with the sewer system within the period prescribed by it, but not less than thirty days from the time when such a connection can be made, as may be prescribed by the local agency.