I have just converted half of my garage to a utility room containing a sink and a washing machine. Unfortunately it is on the opposite side of the house from the drains. A 40mm pipe runs from the sink trap to an opening in the wall (the bottom of the pipe is 50mm above ground level). Can I run a 40mm pipe from the wll opening to the inspection chamber which is 8 metres away by burying the pipe underground and making a hole in the side of the inspection chamber to take the pipe? If not how would I do it?