I have a series of sinks with three vents and a single shared drain on ground level. All plumbing described here is on a single plane in a wall, with the trap adapters extending outward (toward the viewer). I want to temporarily replace two of the sinks with units having lower outlets than will work with the current drain pipe level (think pedestal sinks). The original traps would be detached and the drains capped. Can I add a new drain run below the original, leaving the original intact? The...
