is ABS suitable for pressurized potable water?

Answer 1

ABS is typically used as drain pipe, not for supply pipe. It isn't approved for use as supply pipe by most codes, so it would fail any inspections if they are going to be done. I would just go ahead and use PVC/CPVC for the supply lines.

Answer 2

ABS is not rated for pressure systems. That is why it is used for sewer drain lines. Copper pipe would be best for potable water, be sure to use lead-free solder. PVC could be used for potable water but is not permitted in many states.