Originally Posted By: Blaine Wiley This post was automatically imported from our archived forum.
Amateur workmanship found at the plumbing drain lines below the kitchen sink. A qualified licensed plumbing contractor should be contacted to make corrections.
Originally Posted By: ahalstead This post was automatically imported from our archived forum.
If the installation is solid (and a trap is present!!) an abs/pvc combination would not bother me. After all, its plastic … not dissimilar metals … doubt you would see any type of galvanic reaction here …
Originally Posted By: roconnor This post was automatically imported from our archived forum.
The trap could be within or below the framing, as long as the tailpiece from the fixture to the trap isn’t any more than 2’ to 3’ (current IRC is 2’ max).
Also, I understand that joints between PVC and ABS can be glued with special solvent cements ... but I am on the fence with that, and would look closely for signs of leaks.
Originally Posted By: roconnor This post was automatically imported from our archived forum.
It’s not common around my neck of the woods to put a sink trap below a slab, but it’s possible. I don’t know about your area.
Maybe talk to some local plumbers about what's common in your area with slab foundations, and just note in reports that you didn't observe a trap below the sink ... so it's either missing or buried below the slab. Can't say much more than that ... Observe & Report, thats the job ... 
-- Robert O'Connor, PE
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NACHI Education Committee
I am absolutely amazed sometimes by how much thought goes into doing things wrong