After framing is done the next step is to build the water and sewer piping to laundry and bathroom. The most time consuming job is plumbing. To trace all the pipes, to choose right connectors, to solder them, and to fit all that stuff to appliances is quite a project.
Compare with the plumbing the sewer is kind of relaxing and enjoying process. Just measure, cut, glue and vu à la you have it done.
It was necessary to relocate some existing pipes, such as furnace exhaust, to make then easer creation of the bulkheads.