My son just bought a house that was built in 1968.......... I want to put in another toilet but unsure yet where to put it. As i was looking around the garage i moved the dryer and underneath the dryer i found a 4in pvc plug. i have included a picture. Could there have been a toilet here before but they pugged the pvc drain and put the laundry machines on top of it? If so how do i remove this plug? The plug is the proper distance from the wall. Thank you.