(a) 
Cross connections.
Potable and nonpotable water supplies shall be distributed through systems entirely independent of each other, and any cross-connection between such supplies is prohibited.
(b) 
Backflow.
Every potable water outlet shall be protected from backflow, preferably by having the outlet end from which the water flows, spaced a distance from the flood level rim of the receptacle into which the water flows, sufficient to provide a “minimum required air gap” as listed in the table below:
Fixtures
Minimum Air Gaps
Lavatories with effective openings not greater than 1/2" in diameter
1.0"
Sinks, laundry trays, and gooseneck bath faucets with effective openings not greater than 3/4" in diameter
1.5"
Overrim bath fillers with effective openings not greater than 1" in diameter
2.0"
Effective openings greater than 1"
2 x effective opening
Where it is not possible to provide a minimum air gap, then the fixture shall be equipped with an accessibly located backflow preventer installed between the control valve and the fixture or outlet. Such backflow preventer shall be of a design approved by the chief plumbing inspector.
Where it is not possible to provide a minimum air gap or backflow preventer, as may be the case in connections to cooling jackets, condensers, or other industrial or special appliances, then the chief plumbing inspector shall require a separate tank supply or such other means of protection as may be practicable and desirable.
(c) 
Water supply tanks.
All potable water supply tanks shall be properly covered to prevent entrance of foreign material into the water supply. Soil or waste lines shall not be permitted to pass directly over such tanks or over manholes in pressure tanks.
(1965 Code, sec. 15-107)
All plumbing fixtures shall be provided with a sufficient supply of water for flushing to keep them in a sanitary condition. Every water closet or urinal shall be flushed by means of an approved tank or flush valve of at least four (4) gallons flushing capacity for water closets, and at least (1) gallon for urinals, and shall be adjusted to prevent the waste of water. The flush pipe for water closet flush tanks shall not be less than 1-1/4" in diameter, and the water from flush tanks shall not be used for other purposes. The fixture supply pipe to all closets and lavatories shall be provided with separate stop cocks with renewal discs. Slip joints will not be permitted on any supply line up to valve.
(1965 Code, sec. 15-108)
A group of urinals in the same room as in schools and factories may be supplied from one automatic flush tank of a capacity equal to one gallon of water to each urinal. Automatic flush must be simultaneous and of such force as to cleanse each individual fixture. Intermittent or automatic flushing devices shall be flushed at regular intervals not to exceed ten minutes during the hours that such fixtures are used. If wall urinals are used, one floor drain shall be installed under the fixtures for each battery of one to three urinals. Walls and floor of room in which urinal or urinals are located shall be of nonabsorbent materials.
(1965 Code, sec. 15-109)
(a) 
Residence and apartment house water service lines sizes shall be installed in accordance with the following table. Sizes set forth in this table do not apply where flush valves are used.
Number of Fixtures
Length of Run
Size
1-5
up to 100'
3/4"
6-8
up to 50'
3/4"
6-8
from 50' to 100'
1"
9-10
up to 100'
1"
11-20
up to 50'
1"
11-20
from 50' to 100'
1-1/4"
For installations not covered by this table, the required size of pipe shall be specified by the city plumbing inspector.
(b) 
The main water supply line to any building or bathroom shall not be smaller than 3/4" pipe and not more than two fixtures shall be supplied by 1/2" pipe.
(c) 
The water service line shall be laid 18" below the surface of the ground and where laid in the street or alley, the pipe shall not be laid less than 22" below surface of the ground. Water pipe run under buildings shall be 8" underground up to the point of risers. Under buildings, water pipes may be supported to floor joists on pipe hangers provided such pipes are covered with 3/4" thick wool felt or equal pipe covering with canvas jackets and metal bands every 18". Fittings on suspended pipes shall be covered with asbestos cement and wrapped in canvas. Pipes on walls outside of buildings shall be covered with nonfrost and antifreeze pipe covering of not less than 1" thickness and with weatherproof jackets for protection against the elements. Fittings shall be covered or wrapped with similar materials. Water pipes in attics and garages and in the outside walls of buildings of other than solid masonry construction and all hot water circulating systems shall be covered with 3/4" thick wool felt pipe covering or other approved covering having the same insulation value. Coverings on all such pipe and fittings shall be installed in accordance with manufacturers specifications.
(1965 Code, sec. 15-110)
(a) 
The water service to each building where there is a bathroom and kitchen sink and known as a residence shall be provided with an automatic compression stop and drain cock with renewable disc of a pattern approved by the city plumbing inspector. Such stop and drain shall be located outside the house but not more than three (3) feet from the foundation wall. On the house side of this valve there shall be a union and the valve and union shall be housed in a box and cover in such a position that valve or union may be removed for repairs or replacements. The box shall be of cast iron not less than 15" x 22" x 12", or precast reinforced concrete of circular design not less than 18" in diameter by 15" deep. The cover for the concrete box shall be cast iron or concrete reinforced with 2" x 2" by no. 12 welded wire mesh. A drainpipe from hot water lines of 1/2" size shall be run to this same box, and a compression stop cock shall be installed on this line and located in the box.
(b) 
In a building where bathroom fixtures, kitchen sink and hot water heater are installed back to back on the same partition wall and the hot and cold water pipes are concealed in this partition and the hot water pipe is installed in such manner as to completely drain the hot water pipes through the bath cock, then a hot water drain will not be required as heretofore specified.
(c) 
Two hose connections shall be provided for each residence; one in front and one in the rear of the building. When sill cocks are used, they may be controlled by the main cutoff as heretofore specified. When yard hydrants are installed, each hydrant shall be controlled by a compression stop and waste located at the base of each riser.
(1965 Code, sec. 15-112)
The water piping in apartments and multiple dwellings in buildings not more than two stories in height shall be installed in accordance with one of the following methods:
(1) 
When a separate water meter is to be installed for each apartment, the installation shall be made in the same manner as described for residence water service. A separate valve box may be installed for each service line or the valves from several lines may be installed in one box, provided that the box is sufficiently large to accommodate all drain cocks and valves contained therein in such a manner that each valve may be removed or repaired without disturbing the other valves in the box. The temperature and pressure relief valve drain lines from not more than four water heaters may discharge to a common relief drain line. Such drain line shall be graded to drain, shall discharge outside the building as specified in section 3.05.308 and shall not be less than 3/4" in size when serving four (4) water heaters.
(2) 
When not more than three apartments are located in one building the water, piping shall be installed as described in (1) above except that one water meter may be used.
(3) 
When one water meter is provided for a building serving four to twelve apartments, the water piping may be installed as described in (1) and (2) above or such piping shall be installed in the following manner: A main shut off valve and drain shall be installed on the main water supply to the building and located in a box as described for residence water service. Such valve and drain may be installed in a basement with a floor drain. All water risers shall be located in inside partition walls. Each fixture shall be provided with an individual compression stop cock accessibly located on hot and cold water supply only. All hot and cold water supply lines shall be covered with 3/8" thick insulation with materials as described in section 3.05.134. When a water heater is installed in each apartment the temperature and pressure relief valve drain line from not more than four (4) water heaters may discharge to a common relief drain line as specified in (1) above.
(4) 
When more than one apartments’ stop, and drain valves are placed in a cutoff box, each valve shall be labeled with a permanent metal tag fixed to the valve identifying the apartment controlled.
(5) 
Plans for the water supply systems for apartment buildings exceeding two stories in height shall be submitted to the chief plumbing inspector for approval.
(1965 Code, sec. 15-113)
Connections to and from hot water heaters shall not be smaller than 3/4" pipe size. Hot water pipe shall not be less than 3/4" size from heater to tee branch or the first fixture.
(1965 Code, sec. 15-114)
The fountain shall be constructed of impervious material, such as vitreous china, porcelain, enameled cast iron, other noncorrosive metals, or stoneware. The jet of the fountain shall issue from a nozzle of nonoxidizing, impervious material set at an angle from the vertical so as to prevent the return of water in the jet to the orifice or orifices from whence the jet issues. The nozzle and every other opening in the water pipe or conductor leading to the nozzle shall be above the flood level of the bowl. The end of the nozzle shall be protected by nonoxidizing guards. Guards shall be so designed that the possibility of transmission of infection by touching the guards is reduced to a minimum. The inclined jet of water issuing from the nozzle shall not touch the guard. The bowl of the fountain shall be so designed and proportioned as to be free from corners and shall be so proportioned as to prevent unnecessary splashing at a point where the jet falls into the bowl. The drain from the fountain shall have a direct physical connection with a waste pipe, and the drain shall be properly trapped and vented. The waste opening and drain shall be of sufficient size to carry off the water promptly. The opening shall be provided with a strainer. The water supply pipe shall be provided with an adjustable valve fitted with a loose key or an automatic valve permitting the regulation of the rate of flow of water to the fountain.
(1965 Code, sec. 15-115)
Every lawn sprinkler system shall be provided with a horizontal swing check valve with a 45-degree seat installed between the water meter and master shutoff valve for the system. Each such system shall be provided with a means of draining and all such piping shall not be less than 12" underground. A backflow preventer shall be installed when required by the plumbing inspector.
(1965 Code, sec. 15-116)
Water wells, pumps, storage basins and appurtenances shall be constructed and maintained in such a manner as to protect the water from contamination and shall be constructed and maintained in accord with the standards promulgated by the state board of health for water supply systems. The well water supply system shall be inspected from time to time by the city sanitary engineer or his authorized representative who shall require that the said standards be complied with.
(1965 Code, sec. 15-117)