Protection of Potable Water Supply
NYC Plumbing Code § PC 608
in effectSection PC 608: Protection of Potable Water Supply
608.1 General.
A potable water supply system shall be designed, installed and maintained in such a manner so as to prevent contamination from nonpotable liquids, solids or gases being introduced into the potable water supply through cross connections or any other piping connections to the system. Backflow preventer applications shall conform to Table 608.1, except as specifically stated in Sections 608.2 through 608.16.10. Primary backflow prevention devices shall comply with the requirements of the Department of Environmental Protection.
Table 608.1
Application of Backflow Preventers
Device Degree of Hazard a Application b Applicable Standards
Backflow prevention assemblies:
Double check backflow prevention assembly Low hazard Backpressure or backsiphonage Sizes 3/8" - 12" ASSE 1015, AWWA C510, CSA B64.5, CSA B64.5.1
Double check detector fire protection backflow prevention assemblies Low hazard Backpressure or backsiphonage Sizes 2" - 12" ASSE 1048
Pressure vacuum breaker assembly High or low hazard Backsiphonage only Sizes 1/2" - 2" ASSE 1020, CSA B64.1.2
Reduced pressure principle backflow preventer High or low hazard Backpressure or backsiphonage Sizes 3/8" - 12" ASSE 1013, AWWA C511, CSA B64.4, CSA B64.4.1
Reduced pressure detector fire protection backflow prevention assemblies High or low hazard Backsiphonage or backpressure ASSE 1047
Spill-resistant vacuum breaker assembly c High or low hazard Backsiphonage only Sizes 1/4" - 2" ASSE 1056
Backflow preventer plumbing devices:
Antisiphon-type fill valves for gravity water closet flush tanks High hazard Backsiphonage only ASSE 1002, CSA B125.3
Backflow preventer for carbonated beverage machines Low hazard Backpressure or backsiphonage Sizes 1/4"- 3/8" ASSE 1022
Backflow preventer with intermediate atmospheric vents Low hazard Backpressure or backsiphonage Sizes 1/4"- 3/8" ASSE 1012, CSA B64.3
Dual-check-valve-type backflow preventer Low hazard Backpressure or backsiphonage Sizes 1/4" - 1" ASSE 1024, CSA B64.6
Hose connection backflow preventer High or low hazard Low head backpressure, rated working pressure, backpressure or backsiphonage Sizes 1/2" - 1" ASME A112.21.3, ASSE 1052, CSA B64.2.1.1
Hose connection vacuum breaker High or low hazard Low head backpressure or backsiphonage Sizes 1/2", 3/4", 1" ASME A112.21.3, ASSE 1011, CSA B64.2, CSA B64.2.1
Laboratory faucet backflow preventer High or low hazard Low head backpressure and backsiphonage ASSE 1035, CSA B64.7
Pipe-applied atmospheric-type vacuum breaker High or low hazard Backsiphonage only Sizes 1/4" - 4" ASSE 1001, CSA B64.1.1
Vacuum breaker wall hydrants, frost-resistant, automatic-draining type High or low hazard Low head backpressure or backsiphonage Sizes 3/4", 1" ASME A112.21.3, ASSE 1019, CSA B64.2.2
Other means or methods:
Air gap High or low hazard Backsiphonage or backpressure ASME A112.1.2
Air gap fittings for use with plumbing fixtures, appliances and appurtenances High or low hazard Backsiphonage or backpressure ASME A112.1.3
Barometric loop High or low hazard Backsiphonage only (See Section 608.13.4)
For SI: 1 inch = 25.4 mm.
a. Low hazard.
High hazard – See Contamination (Section 202).
b. See Backpressure, low head (Section 202).
See Backsiphonage (Section 202).
c. The regulations of the Department of Environmental Protection prohibit use of vacuum breaker assemblies as primary backflow prevention devices.
608.2 Plumbing fixtures.
The supply lines and fittings for plumbing fixtures shall be installed so as to prevent backflow. Plumbing fixture fittings shall provide backflow protection in accordance with ASME A112.18.1/CSA B125.1.
608.3 Devices, appurtenances, appliances and apparatus.
Devices, appurtenances, appliances and apparatus intended to serve some special function, such as sterilization, distillation, processing, cooling, or storage of ice or foods, and that connect to the water supply system, shall be provided with protection against backflow and contamination of the water supply system. Water pumps, filters, softeners, tanks and other appliances and devices that handle or treat potable water shall be protected against contamination.
608.3.1 Special equipment, water supply protection.
The water supply for hospital fixtures shall be protected against backflow with a reduced pressure principle backflow prevention assembly, an atmospheric or spill-resistant vacuum breaker, assembly or an air gap. Vacuum breakers for bedpan washer hoses shall not be located less than 5 feet (1524 mm) above the floor. Vacuum breakers for hose connections in health care or laboratory areas shall not be less than 6 feet (1829 mm) above the floor.
608.4 Water service piping.
Water service piping shall be protected in accordance with Sections 603.2 and 603.2.1.
608.5 Chemicals and other substances.
Chemicals and other substances that produce either toxic conditions, taste, odor or discoloration in a potable water system shall not be introduced into, or utilized in, such systems.
608.6 Cross connection control.
Cross connections shall be prohibited, except where approved backflow prevention assemblies, backflow prevention devices or other means or methods are installed to protect the potable water supply.
608.6.1 Private water supplies.
Cross connections between a private water supply and a potable public supply shall be prohibited.
608.7 Valves and outlets prohibited below grade.
Potable water outlets and combination stop-and-waste valves shall not be installed underground or below grade. Freezeproof yard hydrants that drain the riser into the ground are considered to be stop-and-waste valves.
Exception: Freezeproof yard hydrants that drain the riser into the ground shall be permitted to be installed, provided that the potable water supply to such hydrants is protected upstream of the hydrants in accordance with Section 608 and the hydrants are permanently identified as nonpotable outlets by approved signage that reads as follows: "Caution, Nonpotable Water. Do Not Drink."
608.8 Identification of nonpotable water systems.
Where nonpotable water systems are installed, the piping conveying the nonpotable water shall be identified either by color marking, metal tags or tape in accordance with Sections 608.8.1 through 608.8.2.3.
608.8.1 Signage required.
Nonpotable water outlets, such as hose connections, open ended pipes and faucets, shall be identified with signage that reads as follows: "Nonpotable water is utilized for (application name). CAUTION: NONPOTABLE WATER – DO NOT DRINK." The words shall be legibly and indelibly printed on a tag or sign constructed of corrosion-resistant waterproof material or shall be indelibly printed on the fixture. The letters of the words shall be not less than 0.5 inch (12.7 mm) in height and in colors in contrast to the background on which they are applied. In addition to the required wordage, the pictograph shown in Figure 608.8.1 shall appear on the required signage.
Figure 608.8.1
Pictograph – Do Not Drink
608.8.2 Distribution pipe labeling and marking.
Nonpotable distribution piping shall be purple in color and shall be embossed, or integrally stamped or marked, with the words: "CAUTION: NONPOTABLE WATER – DO NOT DRINK" or the piping shall be installed with a purple identification tape or wrap. Pipe identification shall include the contents of the piping system and an arrow indicating the direction of flow. Hazardous piping systems shall also contain information addressing the nature of the hazard. Pipe identification shall be repeated at intervals not exceeding 25 feet (7620 mm) and at each point where the piping passes through a wall, floor or roof. Lettering shall be readily observable within the room or space where the piping is located.
608.8.2.1 Color.
The color of the pipe identification shall be discernable and consistent throughout the building. The color purple shall be used to identify nonpotable water distribution systems.
608.8.2.2 Lettering size.
The size of the background color field and lettering shall comply with Table 608.8.2.2.
Table 608.8.2.2
Size of Pipe Identification
Pipe Diameter (inches) Length Background Color Field (inches) Size of Letters (inches)
3/4 to 1 1/4 8 0.5
1 1/2 to 2 8 0.75
2 1/2 to 6 12 1.25
8 to 10 24 2.5
over 10 32 3.5
For SI: 1 inch = 25.4 mm.
608.8.2.3 Identification tape.
Where used, identification tape shall be at least 3 inches (76 mm) wide and have white or black lettering on a purple field stating "CAUTION: NONPOTABLE WATER – DO NOT DRINK." Identification tape shall be installed on top of nonpotable water distribution pipes, fastened at least every 10 feet (3048 mm) to each pipe length and run continuously the entire length of the pipe.
608.9 Reutilization prohibited.
Water utilized for the cooling of equipment or other processes shall not be returned to the potable water system. Such water shall be discharged into a drainage system through an air gap or shall be utilized for nonpotable purposes.
608.10 Reuse of piping.
Piping that has been utilized for any purpose other than conveying potable water shall not be utilized for conveying potable water.
608.11 Painting of water tanks.
The interior surface of a potable water tank shall not be lined, painted or repaired with any material that changes the taste, odor, color or potability of the water supply when the tank is placed in, or returned to, service. Linings, paints, and repairs must be in accordance with the requirements of the Department of Health and Mental Hygiene.
608.12 Pumps and other appliances.
Water pumps, filters, softeners, tanks and other devices that handle or treat potable water shall be protected against contamination.
608.13 Backflow protection.
Means of protection against secondary backflow shall be provided in accordance with Sections 608.13.1 through 608.13.10 and tested and inspected in accordance with Chapter 3.
608.13.1 Air gap.
The minimum required air gap shall be measured vertically from the lowest end of a potable water outlet to the flood level rim of the fixture or receptacle into which such potable water outlet discharges. Air gaps shall comply with ASME A112.1.2 and air gap fittings shall comply with ASME A112.1.3.
608.13.2 Reduced pressure principle backflow prevention assemblies.
Reduced pressure principle backflow prevention assemblies shall conform to ASSE 1013, AWWA C511, CSA B64.4 or CSA B64.4.1. Reduced pressure detector assembly backflow preventers shall conform to ASSE 1047. These devices shall be permitted to be installed where subject to continuous pressure conditions. The relief opening shall discharge by air gap and shall be prevented from being submerged.
608.13.3 Backflow preventer with intermediate atmospheric vent.
Backflow preventers with intermediate atmospheric vents shall conform to ASSE 1012 or CSA B64.3. These devices shall be permitted to be installed where subject to continuous pressure conditions. The relief opening shall discharge by air gap and shall be prevented from being submerged.
608.13.4 Barometric loop.
Barometric loops shall precede the point of connection and shall extend vertically to a height of 35 feet (10 668 mm). A barometric loop shall only be utilized as an atmospheric-type or pressure-type vacuum breaker.
608.13.5 Pressure vacuum breaker assemblies.
Pressure vacuum breaker assemblies shall conform to ASSE 1020 or CSA B64.1.2. Spill-resistant vacuum breaker assemblies shall comply with ASSE 1056. These assemblies are designed for installation under continuous pressure conditions where the critical level is installed at the required height. Pressure vacuum breaker assemblies shall not be installed in locations where spillage could cause damage to the structure.
608.13.6 Atmospheric-type vacuum breakers.
Pipe applied atmospheric-type vacuum breakers shall conform to ASSE 1001 or CSA B64.1.1. Hose-connection vacuum breakers shall conform to ASME A112.21.3, ASSE 1011, ASSE 1019, ASSE 1035, ASSE 1052, CSA B64.2, CSA B64.2.1, CSA B64.2.1.1, CSA B64.2.2 or CSA B64.7. These devices shall operate under normal atmospheric pressure when the critical level is installed at the required height.
608.13.7 Double check backflow prevention assemblies.
Double check backflow prevention assemblies shall conform to ASSE 1015, CSA B64.5, CSA B64.5.1 or AWWA C510. Double check detector fire protection backflow prevention assemblies shall conform to ASSE 1048. These assemblies shall be capable of operating under continuous pressure conditions.
608.13.8 Spill-resistant pressure vacuum breaker assemblies.
Spill-resistant pressure vacuum breaker assemblies shall conform to ASSE 1056 or CSA B64.1.3. These assemblies are designed for installation under continuous-pressure conditions where the critical level is installed at the required height.
608.13.9 Chemical dispenser backflow devices.
Backflow devices for chemical dispensers shall comply with ASSE 1055 or shall be equipped with an air gap fitting.
608.13.10 Dual check backflow preventer.
Dual check backflow preventers shall conform to ASSE 1024 or CSA B64.6.
608.14 Location of backflow preventers.
Access shall be provided to backflow preventers as specified by the manufacturer's instructions.
608.14.1 Outdoor enclosures for backflow prevention devices.
Outdoor enclosures for backflow prevention devices shall comply with ASSE 1060.
608.14.2 Protection of backflow preventers.
Backflow preventers shall not be located in areas subject to freezing except where they can be removed by means of unions or are protected from freezing by heat, insulation or both.
608.14.2.1 Relief port piping.
The termination of the piping from the relief port or air gap fitting of a backflow preventer shall discharge to an approved indirect waste receptor or to the outdoors where it will not cause damage or create a nuisance.
608.15 Protection of potable water outlets.
All potable water openings and outlets shall be protected against backflow in accordance with Section 608.15.1, 608.15.2, 608.15.3, 608.15.4, 608.15.4.1 or 608.15.4.2.
608.15.1 Protection by air gap.
Openings and outlets shall be protected by an air gap between the opening and the fixture flood level rim as specified in Table 608.15.1. Openings and outlets equipped for hose connection shall be protected by means other than an air gap.
Table 608.15.1
Minimum Required Air Gaps
Fixture Minimum Air Gap
Away from a Wall a (inches) Close to a Wall (inches)
Lavatories and other fixtures with effective openings not greater than 1/2 inch in diameter 1 1 1/2
Sinks, laundry trays, gooseneck back faucets and other fixtures with effective openings not greater than 3/4 inch in diameter 1 1/2 2 1/2
Over-rim bath fillers and other fixtures with effective openings not greater than 1 inch in diameter 2 3
Drinking water fountains, single orifice not greater than 7/16 inch in diameter or multiple orifices with a total area of 0.150 square inch (area of circle 7/16 inch in diameter) 1 1 1/2
Effective openings greater than 1 inch Two times the diameter of the effective opening Three times the diameter of the effective opening
For SI: 1 inch = 25.4 mm, 1 square inch = 645 mm2.
a. Applicable where walls or obstructions are spaced from the nearest inside-edge of the spout opening a distance greater than three times the diameter of the effective opening for a single wall, or a distance greater than four times the diameter of the effective opening for two intersecting walls.
608.15.2 Protection by reduced pressure principle backflow prevention assembly.
Openings and outlets shall be protected by a reduced pressure principle backflow prevention assembly or a reduced pressure principle fire protection backflow prevention assembly on potable water supplies.
608.15.3 Protection by a backflow preventer with intermediate atmospheric vent.
Openings and outlets shall be protected by a backflow preventer with an intermediate atmospheric vent.
608.15.4 Protection by a vacuum breaker.
Openings and outlets shall be protected by atmospheric-type or pressure-type vacuum breakers. The critical level of the vacuum breaker shall be set not less than 6 inches (152 mm) above the flood level rim of the fixture or device. Fill valves shall be set in accordance with Section 425.3.1. Vacuum breakers shall not be installed under exhaust hoods or similar that will contain toxic fumes or vapors. Pipe-applied vacuum breakers shall be installed not less than 6 inches (152 mm) above the flood level rim of the fixture, receptor or device served.
608.15.4.1 Deck-mounted and integral vacuum breakers.
Approved deck-mounted or equipment mounted vacuum breakers and faucets with integral atmospheric vacuum breakers or spill-resistant vacuum breaker assemblies shall be installed in accordance with the manufacturer's instructions and the requirements for labeling with the critical level not less than 1 inch (25 mm) above the flood level rim.
608.15.4.2 Hose connections.
Sillcocks, hose bibbs, wall hydrants and other openings with a hose connection shall be protected by an atmospheric -type or pressure-type vacuum breaker or a permanently attached hose connection vacuum breaker.
Exceptions:
1. This section shall not apply to water heater and boiler drain valves that are provided with hose connection threads and that are intended only for tank or vessel draining.
2. This section shall not apply to water supply valves intended for connection of clothes washing machines where backflow prevention is otherwise provided or is integral with the machine.
608.16 Connections to the potable water system.
Connections to the potable water system shall conform to Sections 608.16.1 through 608.16.10.
608.16.1 Beverage dispensers.
The water supply connection to beverage dispensers shall be protected against backflow by a backflow preventer conforming to ASSE 1022 or by an air gap. The portion of the backflow preventer device downstream from the second check valve and the piping downstream therefrom shall not be affected by carbon dioxide gas.
608.16.2 Connections to boilers.
The potable supply to the boiler shall be protected by an air gap or a reduced pressure principle backflow preventer, complying with ASSE 1013, CSA B64.4 or AWWA C511.
Exception: An atmospheric vent complying with ASSE 1012 or CSA B64.3 may be installed in buildings classified as Occupancy Group R-3 and which do not utilize conditioning chemicals.
Editor's note: For related unconsolidated provisions, see Appendix A at L.L. 2010/056.
608.16.3 Heat exchangers.
Heat exchangers utilizing an essentially toxic transfer fluid shall be separated from the potable water by double-wall construction. An air gap open to the atmosphere shall be provided between the two walls. Heat exchangers utilizing an essentially nontoxic transfer fluid shall be permitted to be of single-wall construction.
Exceptions: Double-wall construction shall not be required for the following:
1. Heat exchangers supplied directly from the Consolidated Edison steam system; and
2. Low-pressure steam-heating boilers.
608.16.4 Connections to automatic fire sprinkler systems and standpipe systems.
The potable water supply to automatic fire sprinkler and standpipe systems shall be protected against backflow by a double check backflow prevention assembly, a double check detector fire protection backflow prevention assembly, reduced pressure principle backflow prevention assembly, or a reduced pressure detector fire protection backflow prevention assembly.
Exceptions:
1. Where systems are installed as a portion of the water distribution system in accordance with the requirements of this code and are not provided with a fire department connection, isolation of the water supply system shall not be required.
2. Isolation of the water distribution system is not required for deluge, preaction or dry pipe systems.
608.16.4.1 Additives or nonpotable source.
Where systems under continuous pressure contain chemical additives or antifreeze, or where systems are connected to a nonpotable secondary water supply, the potable water supply shall be protected against backflow by a reduced pressure principle backflow prevention assembly or a reduced pressure detector fire protection backflow prevention assembly. Where chemical additives or antifreeze are added to only a portion of an automatic fire sprinkler or standpipe system, the reduced pressure principle backflow prevention assembly or the reduced pressure detector fire protection backflow prevention assembly shall be permitted to be located so as to isolate that portion of the system. Where systems are not under continuous pressure, the potable water supply shall be protected against backflow by an air gap or an atmospheric vacuum breaker conforming to ASSE 1001 or CSA B64.1.1.
608.16.5 Connections to lawn irrigation systems.
The potable water supply to lawn irrigation systems shall be protected against backflow by an atmospheric vacuum breaker, a pressure vacuum breaker assembly or a reduced pressure principle backflow prevention assembly. Valves shall not be installed downstream from an atmospheric vacuum breaker. Where chemicals are introduced into the system, the potable water supply shall be protected against backflow by a reduced pressure principle backflow prevention assembly.
608.16.6 Connections subject to backpressure.
Where a potable water connection is made to a nonpotable line, fixture, tank, vat, pump, cooling tower or other equipment subject to high-hazard backpressure, the potable water connection shall be protected by a reduced pressure principle backflow prevention assembly.
608.16.7 Chemical dispensers.
Where chemical dispensers connect to the potable water distribution system, the water supply system shall be protected against backflow in accordance with Section 608.13.1, 608.13.2, 608.13.5, 608.13.6, 608.13.8 or 608.13.9.
608.16.8 Portable cleaning equipment.
Where the portable cleaning equipment connects to the water distribution system, the water supply system shall be protected against backflow in accordance with Section 608.13.1, 608.13.2, 608.13.3, 608.13.7 or 608.13.8.
608.16.9 Dental pump equipment.
Where dental pumping equipment connects to the water distribution system, the water supply system shall be protected against backflow in accordance with Section 608.13.1, 608.13.2, 608.13.5, 608. 13.6 or 608.13.8.
608.16.10 Coffee machines and noncarbonated beverage dispensers.
The water supply connection to coffee machines and noncarbonated beverage dispensers shall be protected against backflow by a backflow preventer conforming to ASSE 1022 or by an air gap.
608.17 Protection of individual water supplies.
An individual water supply shall be located and constructed so as to be safeguarded against contamination in accordance with Sections 608.17.1 through 608.17.8.
608.17.1 Well locations.
A potable ground water source or pump suction line shall not be located closer to potential sources of contamination than the distances shown in Table 608.17.1. In the event the underlying rock structure is limestone or fragmented shale, the local or state health department shall be consulted on well site location. The distances in Table 608.17.1 constitute minimum separation and shall be increased in areas of creviced rock or limestone, or where the direction of movement of the ground water is from sources of contamination toward the well.
Table 608.17.1
Distance from Contamination to Private Water Supplies and Pump Suction Lines
Source of Contamination Distance (feet)
Barnyard 100
Farm silo 25
Pasture 100
Pumphouse floor drain of cast iron draining to ground surface 2
Seepage pits 50
Septic tank 25
Sewer 10
Subsurface disposal fields 50
Subsurface pits 50
For SI: 1 foot = 304.8 mm.
608.17.2 Elevation.
Well sites shall be positively drained and shall be at higher elevations than potential sources of contamination.
608.17.3 Depth.
Private potable well supplies shall not be developed from a water table less than 10 feet (3048 mm) below the ground surface.
608.17.4 Water-tight casings.
Each well shall be provided with a water-tight casing extending to 10 feet (3048 mm) below the ground surface. Casings shall extend not less than 6 inches (152 mm) above the well platform. Casings shall be large enough to permit installation of a separate drop pipe. Casings shall be sealed at the bottom in an impermeable stratum or extend several feet into the water-bearing stratum.
608.17.5 Drilled or driven well casings.
Drilled or driven well casings shall be of steel or other approved material. Where drilled wells extend into a rock formation, the well casing shall extend to and set firmly in the formation. The annular space between the earth and the outside of the casing shall be filled with cement grout to a depth of not less than 10 feet (3048 mm) below the ground surface. In an instance of casing to rock installation, the grout shall extend to the rock surface.
608.17.6 Dug or bored well casings.
Dug or bored well casings shall be of water-tight concrete, tile or galvanized or corrugated metal pipe extending to not less than 10 feet (3048 mm) below the ground surface. Where the water table is more than 10 feet (3048 mm) below the ground surface, the water-tight casing shall extend below the table surface. Well casings for dug wells or bored wells constructed with sections of concrete, tile or galvanized or corrugated metal pipe shall be surrounded by 6 inches (152 mm) of grout poured into the hole between the outside of the casing and the ground and extending not less than 10 feet (3048 mm) below the ground surface.
608.17.7 Cover.
Potable water wells shall be equipped with an overlapping water-tight cover at the top of the well casing or pipe sleeve such that contaminated water or other substances are prevented from entering the well through the annular opening at the top of the well casing, wall or pipe sleeve. Covers shall extend downward not less than 2 inches (51 mm) over the outside of the well casing or wall. A dug well cover shall be provided with a pipe sleeve permitting the withdrawal of the pump suction pipe, cylinder or jet body without disturbing the cover. Where pump sections or discharge pipes enter or leave a well through the side of the casing, the circle of contact shall be water tight.
608.17.8 Drainage.
Potable water wells and springs shall be constructed such that surface drainage will be diverted away from the well or spring.
Figure 608.8.1
Pictograph – Do Not Drink
608.8.2 Distribution pipe labeling and marking.
Nonpotable distribution piping shall be purple in color and shall be embossed, or integrally stamped or marked, with the words: "CAUTION: NONPOTABLE WATER – DO NOT DRINK" or the piping shall be installed with a purple identification tape or wrap. Pipe identification shall include the contents of the piping system and an arrow indicating the direction of flow. Hazardous piping systems shall also contain information addressing the nature of the hazard. Pipe identification shall be repeated at intervals not exceeding 25 feet (7620 mm) and at each point where the piping passes through a wall, floor or roof. Lettering shall be readily observable within the room or space where the piping is located.
608.8.2.1 Color.
The color of the pipe identification shall be discernable and consistent throughout the building. The color purple shall be used to identify nonpotable water distribution systems.
608.8.2.2 Lettering size.
The size of the background color field and lettering shall comply with Table 608.8.2.2.
Table 608.8.2.2
Size of Pipe Identification
Pipe Diameter (inches) Length Background Color Field (inches) Size of Letters (inches)
3/4 to 1 1/4 8 0.5
1 1/2 to 2 8 0.75
2 1/2 to 6 12 1.25
8 to 10 24 2.5
over 10 32 3.5
For SI: 1 inch = 25.4 mm.
608.8.2.3 Identification tape.
Where used, identification tape shall be at least 3 inches (76 mm) wide and have white or black lettering on a purple field stating "CAUTION: NONPOTABLE WATER – DO NOT DRINK." Identification tape shall be installed on top of nonpotable water distribution pipes, fastened at least every 10 feet (3048 mm) to each pipe length and run continuously the entire length of the pipe.
608.9 Reutilization prohibited.
Water utilized for the cooling of equipment or other processes shall not be returned to the potable water system. Such water shall be discharged into a drainage system through an air gap or shall be utilized for nonpotable purposes.
608.10 Reuse of piping.
Piping that has been utilized for any purpose other than conveying potable water shall not be utilized for conveying potable water.
608.11 Painting of water tanks.
The interior surface of a potable water tank shall not be lined, painted or repaired with any material that changes the taste, odor, color or potability of the water supply when the tank is placed in, or returned to, service. Linings, paints, and repairs must be in accordance with the requirements of the Department of Health and Mental Hygiene.
608.12 Pumps and other appliances.
Water pumps, filters, softeners, tanks and other devices that handle or treat potable water shall be protected against contamination.
608.13 Backflow protection.
Means of protection against secondary backflow shall be provided in accordance with Sections 608.13.1 through 608.13.10 and tested and inspected in accordance with Chapter 3.
608.13.1 Air gap.
The minimum required air gap shall be measured vertically from the lowest end of a potable water outlet to the flood level rim of the fixture or receptacle into which such potable water outlet discharges. Air gaps shall comply with ASME A112.1.2 and air gap fittings shall comply with ASME A112.1.3.
608.13.2 Reduced pressure principle backflow prevention assemblies.
Reduced pressure principle backflow prevention assemblies shall conform to ASSE 1013, AWWA C511, CSA B64.4 or CSA B64.4.1. Reduced pressure detector assembly backflow preventers shall conform to ASSE 1047. These devices shall be permitted to be installed where subject to continuous pressure conditions. The relief opening shall discharge by air gap and shall be prevented from being submerged.
608.13.3 Backflow preventer with intermediate atmospheric vent.
Backflow preventers with intermediate atmospheric vents shall conform to ASSE 1012 or CSA B64.3. These devices shall be permitted to be installed where subject to continuous pressure conditions. The relief opening shall discharge by air gap and shall be prevented from being submerged.
608.13.4 Barometric loop.
Barometric loops shall precede the point of connection and shall extend vertically to a height of 35 feet (10 668 mm). A barometric loop shall only be utilized as an atmospheric-type or pressure-type vacuum breaker.
608.13.5 Pressure vacuum breaker assemblies.
Pressure vacuum breaker assemblies shall conform to ASSE 1020 or CSA B64.1.2. Spill-resistant vacuum breaker assemblies shall comply with ASSE 1056. These assemblies are designed for installation under continuous pressure conditions where the critical level is installed at the required height. Pressure vacuum breaker assemblies shall not be installed in locations where spillage could cause damage to the structure.
608.13.6 Atmospheric-type vacuum breakers.
Pipe applied atmospheric-type vacuum breakers shall conform to ASSE 1001 or CSA B64.1.1. Hose-connection vacuum breakers shall conform to ASME A112.21.3, ASSE 1011, ASSE 1019, ASSE 1035, ASSE 1052, CSA B64.2, CSA B64.2.1, CSA B64.2.1.1, CSA B64.2.2 or CSA B64.7. These devices shall operate under normal atmospheric pressure when the critical level is installed at the required height.
608.13.7 Double check backflow prevention assemblies.
Double check backflow prevention assemblies shall conform to ASSE 1015, CSA B64.5, CSA B64.5.1 or AWWA C510. Double check detector fire protection backflow prevention assemblies shall conform to ASSE 1048. These assemblies shall be capable of operating under continuous pressure conditions.
608.13.8 Spill-resistant pressure vacuum breaker assemblies.
Spill-resistant pressure vacuum breaker assemblies shall conform to ASSE 1056 or CSA B64.1.3. These assemblies are designed for installation under continuous-pressure conditions where the critical level is installed at the required height.
608.13.9 Chemical dispenser backflow devices.
Backflow devices for chemical dispensers shall comply with ASSE 1055 or shall be equipped with an air gap fitting.
608.13.10 Dual check backflow preventer.
Dual check backflow preventers shall conform to ASSE 1024 or CSA B64.6.
608.14 Location of backflow preventers.
Access shall be provided to backflow preventers as specified by the manufacturer's instructions.
608.14.1 Outdoor enclosures for backflow prevention devices.
Outdoor enclosures for backflow prevention devices shall comply with ASSE 1060.
608.14.2 Protection of backflow preventers.
Backflow preventers shall not be located in areas subject to freezing except where they can be removed by means of unions or are protected from freezing by heat, insulation or both.
608.14.2.1 Relief port piping.
The termination of the piping from the relief port or air gap fitting of a backflow preventer shall discharge to an approved indirect waste receptor or to the outdoors where it will not cause damage or create a nuisance.
608.15 Protection of potable water outlets.
All potable water openings and outlets shall be protected against backflow in accordance with Section 608.15.1, 608.15.2, 608.15.3, 608.15.4, 608.15.4.1 or 608.15.4.2.
608.15.1 Protection by air gap.
Openings and outlets shall be protected by an air gap between the opening and the fixture flood level rim as specified in Table 608.15.1. Openings and outlets equipped for hose connection shall be protected by means other than an air gap.
Table 608.15.1
Minimum Required Air Gaps
Fixture Minimum Air Gap
Away from a Wall a (inches) Close to a Wall (inches)
Lavatories and other fixtures with effective openings not greater than 1/2 inch in diameter 1 1 1/2
Sinks, laundry trays, gooseneck back faucets and other fixtures with effective openings not greater than 3/4 inch in diameter 1 1/2 2 1/2
Over-rim bath fillers and other fixtures with effective openings not greater than 1 inch in diameter 2 3
Drinking water fountains, single orifice not greater than 7/16 inch in diameter or multiple orifices with a total area of 0.150 square inch (area of circle 7/16 inch in diameter) 1 1 1/2
Effective openings greater than 1 inch Two times the diameter of the effective opening Three times the diameter of the effective opening
For SI: 1 inch = 25.4 mm, 1 square inch = 645 mm2.
a. Applicable where walls or obstructions are spaced from the nearest inside-edge of the spout opening a distance greater than three times the diameter of the effective opening for a single wall, or a distance greater than four times the diameter of the effective opening for two intersecting walls.
608.15.2 Protection by reduced pressure principle backflow prevention assembly.
Openings and outlets shall be protected by a reduced pressure principle backflow prevention assembly or a reduced pressure principle fire protection backflow prevention assembly on potable water supplies.
608.15.3 Protection by a backflow preventer with intermediate atmospheric vent.
Openings and outlets shall be protected by a backflow preventer with an intermediate atmospheric vent.
608.15.4 Protection by a vacuum breaker.
Openings and outlets shall be protected by atmospheric-type or pressure-type vacuum breakers. The critical level of the vacuum breaker shall be set not less than 6 inches (152 mm) above the flood level rim of the fixture or device. Fill valves shall be set in accordance with Section 425.3.1. Vacuum breakers shall not be installed under exhaust hoods or similar that will contain toxic fumes or vapors. Pipe-applied vacuum breakers shall be installed not less than 6 inches (152 mm) above the flood level rim of the fixture, receptor or device served.
608.15.4.1 Deck-mounted and integral vacuum breakers.
Approved deck-mounted or equipment mounted vacuum breakers and faucets with integral atmospheric vacuum breakers or spill-resistant vacuum breaker assemblies shall be installed in accordance with the manufacturer's instructions and the requirements for labeling with the critical level not less than 1 inch (25 mm) above the flood level rim.
608.15.4.2 Hose connections.
Sillcocks, hose bibbs, wall hydrants and other openings with a hose connection shall be protected by an atmospheric -type or pressure-type vacuum breaker or a permanently attached hose connection vacuum breaker.
Exceptions:
1. This section shall not apply to water heater and boiler drain valves that are provided with hose connection threads and that are intended only for tank or vessel draining.
2. This section shall not apply to water supply valves intended for connection of clothes washing machines where backflow prevention is otherwise provided or is integral with the machine.
608.16 Connections to the potable water system.
Connections to the potable water system shall conform to Sections 608.16.1 through 608.16.10.
608.16.1 Beverage dispensers.
The water supply connection to beverage dispensers shall be protected against backflow by a backflow preventer conforming to ASSE 1022 or by an air gap. The portion of the backflow preventer device downstream from the second check valve and the piping downstream therefrom shall not be affected by carbon dioxide gas.
608.16.2 Connections to boilers.
The potable supply to the boiler shall be protected by an air gap or a reduced pressure principle backflow preventer, complying with ASSE 1013, CSA B64.4 or AWWA C511.
Exception: An atmospheric vent complying with ASSE 1012 or CSA B64.3 may be installed in buildings classified as Occupancy Group R-3 and which do not utilize conditioning chemicals.
Editor's note: For related unconsolidated provisions, see Appendix A at L.L. 2010/056.
608.16.3 Heat exchangers.
Heat exchangers utilizing an essentially toxic transfer fluid shall be separated from the potable water by double-wall construction. An air gap open to the atmosphere shall be provided between the two walls. Heat exchangers utilizing an essentially nontoxic transfer fluid shall be permitted to be of single-wall construction.
Exceptions: Double-wall construction shall not be required for the following:
1. Heat exchangers supplied directly from the Consolidated Edison steam system; and
2. Low-pressure steam-heating boilers.
608.16.4 Connections to automatic fire sprinkler systems and standpipe systems.
The potable water supply to automatic fire sprinkler and standpipe systems shall be protected against backflow by a double check backflow prevention assembly, a double check detector fire protection backflow prevention assembly, reduced pressure principle backflow prevention assembly, or a reduced pressure detector fire protection backflow prevention assembly.
Exceptions:
1. Where systems are installed as a portion of the water distribution system in accordance with the requirements of this code and are not provided with a fire department connection, isolation of the water supply system shall not be required.
2. Isolation of the water distribution system is not required for deluge, preaction or dry pipe systems.
608.16.4.1 Additives or nonpotable source.
Where systems under continuous pressure contain chemical additives or antifreeze, or where systems are connected to a nonpotable secondary water supply, the potable water supply shall be protected against backflow by a reduced pressure principle backflow prevention assembly or a reduced pressure detector fire protection backflow prevention assembly. Where chemical additives or antifreeze are added to only a portion of an automatic fire sprinkler or standpipe system, the reduced pressure principle backflow prevention assembly or the reduced pressure detector fire protection backflow prevention assembly shall be permitted to be located so as to isolate that portion of the system. Where systems are not under continuous pressure, the potable water supply shall be protected against backflow by an air gap or an atmospheric vacuum breaker conforming to ASSE 1001 or CSA B64.1.1.
608.16.5 Connections to lawn irrigation systems.
The potable water supply to lawn irrigation systems shall be protected against backflow by an atmospheric vacuum breaker, a pressure vacuum breaker assembly or a reduced pressure principle backflow prevention assembly. Valves shall not be installed downstream from an atmospheric vacuum breaker. Where chemicals are introduced into the system, the potable water supply shall be protected against backflow by a reduced pressure principle backflow prevention assembly.
608.16.6 Connections subject to backpressure.
Where a potable water connection is made to a nonpotable line, fixture, tank, vat, pump, cooling tower or other equipment subject to high-hazard backpressure, the potable water connection shall be protected by a reduced pressure principle backflow prevention assembly.
608.16.7 Chemical dispensers.
Where chemical dispensers connect to the potable water distribution system, the water supply system shall be protected against backflow in accordance with Section 608.13.1, 608.13.2, 608.13.5, 608.13.6, 608.13.8 or 608.13.9.
608.16.8 Portable cleaning equipment.
Where the portable cleaning equipment connects to the water distribution system, the water supply system shall be protected against backflow in accordance with Section 608.13.1, 608.13.2, 608.13.3, 608.13.7 or 608.13.8.
608.16.9 Dental pump equipment.
Where dental pumping equipment connects to the water distribution system, the water supply system shall be protected against backflow in accordance with Section 608.13.1, 608.13.2, 608.13.5, 608. 13.6 or 608.13.8.
608.16.10 Coffee machines and noncarbonated beverage dispensers.
The water supply connection to coffee machines and noncarbonated beverage dispensers shall be protected against backflow by a backflow preventer conforming to ASSE 1022 or by an air gap.
608.17 Protection of individual water supplies.
An individual water supply shall be located and constructed so as to be safeguarded against contamination in accordance with Sections 608.17.1 through 608.17.8.
608.17.1 Well locations.
A potable ground water source or pump suction line shall not be located closer to potential sources of contamination than the distances shown in Table 608.17.1. In the event the underlying rock structure is limestone or fragmented shale, the local or state health department shall be consulted on well site location. The distances in Table 608.17.1 constitute minimum separation and shall be increased in areas of creviced rock or limestone, or where the direction of movement of the ground water is from sources of contamination toward the well.
Table 608.17.1
Distance from Contamination to Private Water Supplies and Pump Suction Lines
Source of Contamination Distance (feet)
Barnyard 100
Farm silo 25
Pasture 100
Pumphouse floor drain of cast iron draining to ground surface 2
Seepage pits 50
Septic tank 25
Sewer 10
Subsurface disposal fields 50
Subsurface pits 50
For SI: 1 foot = 304.8 mm.
608.17.2 Elevation.
Well sites shall be positively drained and shall be at higher elevations than potential sources of contamination.
608.17.3 Depth.
Private potable well supplies shall not be developed from a water table less than 10 feet (3048 mm) below the ground surface.
608.17.4 Water-tight casings.
Each well shall be provided with a water-tight casing extending to 10 feet (3048 mm) below the ground surface. Casings shall extend not less than 6 inches (152 mm) above the well platform. Casings shall be large enough to permit installation of a separate drop pipe. Casings shall be sealed at the bottom in an impermeable stratum or extend several feet into the water-bearing stratum.
608.17.5 Drilled or driven well casings.
Drilled or driven well casings shall be of steel or other approved material. Where drilled wells extend into a rock formation, the well casing shall extend to and set firmly in the formation. The annular space between the earth and the outside of the casing shall be filled with cement grout to a depth of not less than 10 feet (3048 mm) below the ground surface. In an instance of casing to rock installation, the grout shall extend to the rock surface.
608.17.6 Dug or bored well casings.
Dug or bored well casings shall be of water-tight concrete, tile or galvanized or corrugated metal pipe extending to not less than 10 feet (3048 mm) below the ground surface. Where the water table is more than 10 feet (3048 mm) below the ground surface, the water-tight casing shall extend below the table surface. Well casings for dug wells or bored wells constructed with sections of concrete, tile or galvanized or corrugated metal pipe shall be surrounded by 6 inches (152 mm) of grout poured into the hole between the outside of the casing and the ground and extending not less than 10 feet (3048 mm) below the ground surface.
608.17.7 Cover.
Potable water wells shall be equipped with an overlapping water-tight cover at the top of the well casing or pipe sleeve such that contaminated water or other substances are prevented from entering the well through the annular opening at the top of the well casing, wall or pipe sleeve. Covers shall extend downward not less than 2 inches (51 mm) over the outside of the well casing or wall. A dug well cover shall be provided with a pipe sleeve permitting the withdrawal of the pump suction pipe, cylinder or jet body without disturbing the cover. Where pump sections or discharge pipes enter or leave a well through the side of the casing, the circle of contact shall be water tight.
608.17.8 Drainage.
Potable water wells and springs shall be constructed such that surface drainage will be diverted away from the well or spring.Source: City of New York, Charter, Administrative Code and Rules (American Legal Publishing XML export, codelibrary.amlegal.com)URL: https://codelibrary.amlegal.com/codes/newyorkcity/latest/NYCadmin/0-0-0-162225Fetched: 10/25/2026