In all buildings occupied as stores, dwellings, lodging houses or boardinghouses, hotels, offices, lofts, workshops, factories or storage houses, there must be at least one water closet in each building. There must be sufficient water closets so that there will never be more than 15 persons to each water closet. In places of public assembly, the number of toilets and the most available location are to be determined by the Superintendent of Buildings.
In lodging houses, there must be one water closet on each floor, and where there are more than 15 persons on any floor, there must be an additional water closet on that floor for every 15 additional persons or fraction thereof.
Separate water closets and toilet rooms must be provided for each sex in buildings used as workshops, lofts, office buildings, factories, hotels and all places of public assembly.
In multiple dwellings and lodging houses, factories, workshops and all public buildings, the entire water closet apartment and sidewalls to a height of six inches from the floor, except at the door, must be made waterproof with asphalt, cement tile, metal or other waterproof material as approved by the Superintendent of Buildings.
In all buildings, the water closet and urinal apartments must be ventilated to the outer air by windows opening to the same lot upon which the building is situated or by a ventilating skylight placed over each room or apartment wherein such fixtures are located.
In all buildings, the outside partition of any water closet or urinal apartment must be airtight and shall extend to the ceiling or shall be independently ceiled over. When necessary to properly light such apartments, the upper part of the partitions must be provided with translucent glass. The interior partitions of such apartments must be dwarfed partitions.
In alteration work where it is not practical to ventilate a water closet or urinal apartment by windows or skylight directly to the outer air, there may be provided a galvanized wrought iron vent duct extended to the outer air which must be equal in area to at least 144 square inches for one water closet or urinal and an additional 72 square inches for each water closet added therein.
Every earthenware water closet with connection through the floor, in all new work and in all alterations, must be set on an approved floor slab of porcelain, slate or other material impervious to moisture, the same to be not less in size than the base of the water closet set thereon. The floor flange shall be soldered to lead or copper bend ready for inspection.
Each water closet and urinal must be flushed from a separate cistern, the water from which is used for no other purpose, or may be flushed through separate flushometer valves, The floor flange shall be soldered to lead or copper bend ready for inspection.
A. 
Supply from tank pressure. Where flushometers are used and are supplied from tank pressure, riser lines shall be 1 1/4 inches in diameter with one-inch branches for water closets and not less than one-half-inch branches for urinals. Individual branches shall not exceed 12 inches in length.
B. 
Supply from street main. Where flushometers are used, supplied with pressure from the street main, the following pipe sizes shall be used [minimum pipe sizes are for copper, brass or lead. Where galvanized pipe is used, increase one pipe size]:
Buildings
Number of Fixtures
Diameter of Riser
(inches)
Diameter of Branch
(inches)
Branch Length, Maximum
(inches)
Diameter of Tap
(inches)
Service Pipe Diameter
(inches)
1-story
2 water closets
1
1
Unlimited
1
1
1 urinal
1
1/2
12'
2-story
4 water closets
1 1/4
1
12
1 1/4
1 1/4
2 urinals
1 1/4
1/2
12
3-story
6 water closets
1 1/2
1
12
1 1/2
1 1/2
3 urinals
1 1/2
1/2
12
For four or more stories or additional fixtures for above table, the diameter of tap, service line, riser, etc., shall be determined by the Superintendent of Buildings.
The overflow of a cistern may discharge into the bowl of a water closet, but in no case shall it connect with any part of the drainage system.
The copper lining of water closets and urinal cistern must not be lighter than ten-ounce copper.
Water closet flush pipes must not be less than 1 1/4 inches and urinal flush pipes one inch in diameter, and if of lead, must not weigh less than 2 1/2 pounds and two pounds per linear foot, Flush couplings must be full size of the pipe.
Rubber connections and elbows are not permitted on flush pipes.
Latrines, trough water closets and similar appliances may be used only on written permit from the Superintendent of Buildings and must be set and arranged as may be required by the terms of the permit.
All urinals must be constructed of materials impervious to moisture and that will not corrode under the action of urine. The floor and wall of the urinal apartments must be lined with similar nonabsorbent and noncorrosive material.
The platforms or treads of urinal stalls must never be connected independently to the plumbing system, nor can they be connected to any safe waste pipe.
Iron trough water closets and trough urinals must be enameled or galvanized.
Wooden washtubs are prohibited, except when used in hotels, restaurants or bottling establishments for washing dishes or bottles. Cement or artificial stone tubs will not be permitted unless approved by the Superintendent of Buildings.