burial depth

Hi All, long time reader of these forums (thanks for all of the knowledge shared!) first time poster. **Update** I contacted the city's chief plubming inspector and he confirmed that code does not require burial and that suspension of the lines was allowed**. A 12-unit 2-storey building that...

I am getting started on adding a basement bath. I tore up the concrete where I plan to tie into the existing 4 inch ABS main drain; about 3 feet from where it leaves the house. The existing pipe is much shallower than I expected: At this location, which is the farthest downstream where I can tie...