The owners of any houses, buildings, or properties used for human occupancy, employment, recreation or other purposes, situated within the city and abutting on any street, alley or right-of-way in which there is now located, or may in the future be located, a public sewer, are hereby required to install, at such owner’s expense, suitable toilet facilities therein and a building sewer connecting such facilities directly with the proper public sewer, and to maintain the same all in accordance with the provisions of this chapter, such compliance to be completed within 30 days after date of official notice from the city to do so; provided, that said public sanitary sewer is located within 200 feet of the property line of such owner and is of such design as to receive and convey by gravity such sewage as may be conveyed to it.