The mechanical systems in plumbing include fixtures, piping and valves. Although operating fixtures to see if they’re working is relatively easy, your inspector will do much more. While operating each fixture in your bathrooms and kitchen he will be considering the effects on the whole plumbing system including leaks, pressure, flow and quality of the existing installation. The piping and valve system of your new home must be in good working order. Old or improperly installed pipes are difficult to repair and often require expensive replacement. Only an experienced eye will pick up badly joined piping on a new installation of clean copper tubing, or consider the limitation of supply piping based on age, type of material and sizing.