Where a public sanitary or combined sewer is not available under the provisions of Article
II, §
137-5, the building sewer shall be connected to a private wastewater disposal system complying with the provisions of this Article.
At such time as a public sewer becomes available to a property served by a private sewage disposal system, as provided in Article
III, §
137-8B, a direct connection shall be made to the public sewer in compliance with this Part
1 within 90 days, and the private sewage disposal system shall be cleaned of sludge and filled with clean bank-run gravel or dirt.