All persons or corporations owning land having access to a public sewer, who have not connected to the public sewers on September 12, 1966, shall be permitted to continue using their then-existing septic tanks for the life of their respective septic tanks. Whenever a septic tank deteriorates to such a degree that it fails to meet the standards of the Indiana Board of Health and of the health and hospital corporation of Marion County, the owner of the septic tank shall immediately connect his real estate to the public sewer. (Ord. 377 § 2, 1966).