New York Consolidated Laws, Multiple Residence Law - MRE § 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.