Connections to existing septic tanks may be continued until such time as a public sewer is available, or the council shall by resolution determine that such connection constitutes a health hazard and shall require the owner of property served by a septic tank to connect to the city sewer. Public sewer is "available" when it is within one hundred (100) feet of the affected property and two hundred (200) feet of the building sewer. (Prior code § 4.108)