My basement has a 3-piece rough-in for a bathroom that I now wish to finish (and my home is less than 1 year old). Where the tub/shower would go, I have a square of dirt (un-cemented)with a capped ABS pipe, with the surrounding floor cemented in. I have 2 questions, 1-is it likely that the p-trap is already installed below the ground, and 2-after completion of the plumbing, is it acceptable (or code) to remove the dirt and fill this area with cement? Any help you can provide would be greatly appreciated.