Hi, I'm having an argument with the plumber & builder & have held up any further work on the slab until I am satisfied with the sanitary drain system piping.

The plumber installed the pvc in one day for a two bath, utility, & kitchen single level home & without a helper.

The drain pvc appears to have multiple problems (to me). Part of the pvc runs inside a foundation trench & would be encased in concrete. The pvc is placed about 4" to 12" below the 4" floor area without backfill at this time. There is a 90 degree bend in one run from a bathtub drain to the main drain. There was no testing done of his work. The plumber & builder say this is OK... Here in the country there are no required inspections.
But the state says the international codes apply for all areas of the state.

Are these valid concerns? Any answers & applicable code reference numbers would be appreciated. Thanks Jerry