Section 171. Water-closet and bath accommodations

1. Every dwelling
  arranged for permanent occupancy shall contain a water-closet  in  every
  apartment.
    2.  The  floor  of  every compartment, bathroom or general toilet room
  shall be made waterproof and such waterproofing shall extend six  inches
  or  more  above the floor so that the floor can be washed or flushed out
  without leaking. No plumbing  or  plumbing  fixture  shall  be  enclosed
  wholly or in part with woodwork.
    3.  Water-closets  may  be  placed  together  in a general toilet room
  provided  such  water-closets  are  supplementary  to  the  water-closet
  accommodations  required  for  the  exclusive  use  of  tenants  of  the
  dwelling, or are  solely  for  the  use  of  business  portions  of  the
  dwelling.
    4.  Every  apartment  arranged for permanent occupancy shall contain a
  bath or shower accessible from every bedroom without passing through any
  other bedroom. In dwellings arranged for transient occupancy there shall
  be at least one shower or bath for every eight resident occupants.
    5. Except as specifically provided otherwise in  this  chapter,  every
  water-closet  compartment  and  bath  or shower room shall have a window
  opening upon a street or upon a lawful court or yard.
    6. In lieu of a required window or skylight, it  shall  be  lawful  to
  install  a  system of mechanical or gravity ventilation for water-closet
  compartments or bathrooms in any portion of a dwelling. Such  system  of
  ventilation  shall  be constructed, arranged and maintained continuously
  to provide at least four changes per hour of the air volume of each such
  water-closet compartment or bathroom.