Reddit reviews 50ft HD Endoscope Camera, SHEKAR 2.0 Megapixel 1200P Borescope Inspection Camera Waterproof Snake Camera with 6 LEDs for Windows PC and MacBook

Sounds like a perfect excuse to order a scope.

Personally, I wouldn't buy a slab-on-grade home with HVAC in the slab unless I could inspect it closely myself. I built a house on a slab for myself a few years ago and all HVAC ducts are above grade.

I did all the plumbing under the slab with solid core PVC. With proper clean-out placement I expect to never have a plumbing problem that can't be easily solved. I wouldn't worry much about the plumbing so long as there are clean-outs.

If I were in your shoes I would be finding an inspection camera to take a look at the condition of the under-slab duct work or finding someone that knows how to use one. Something like this...

https://www.amazon.com/Endoscope-Borescope-Waterproof-Inspection-Adjustable/dp/B01N19YCC3

I've thought about getting a waterproof camera. Something like this.https://www.amazon.com/Endoscope-Borescope-Waterproof-Inspection-Adjustable/dp/B01N19YCC3


Then buy a manual snake and slap them together. I need to think more about it, really trying to do this on my own.