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Chapter 6 — WATER SUPPLY AND DISTRIBUTION

603.5 Specific Requirements. Specific requirements for

California Plumbing Code (Title 24, Part 5) · 2019 edition · updated 2026-09-10 · California

Italicized text is a California amendment to the model code, as printed in the official publication.

backflow prevention shall comply with Section 603.5.1 through Section 603.5.21.

603.5.1 Atmospheric Vacuum Breaker. Water closet and urinal flushometer valves shall be protected against backflow by an approved backflow prevention assembly, device, or method. Where the valves are equipped with an atmospheric vacuum breaker, the vacuum breaker shall be installed on the discharge side of the flushometer valve with the critical level not less than 6 inches (152 mm), or the distance according to its listing, above the overflow rim of a water closet bowl or the highest part of a urinal. 603.5.2 Ballcock. Water closet and urinal tanks shall be equipped with a ballcock. The ballcock shall be installed with the critical level not less than 1 inch (25.4

mm) above the full opening of the overflow pipe. In cases where the ballcock has no hush tube, the bottom of the water supply inlet shall be installed 1 inch (25.4 mm) above the full opening of the overflow pipe. 603.5.3 Backflow Prevention. Water closet flushometer tanks shall be protected against backflow by an approved backflow prevention assembly, device, or method. 603.5.4 Heat Exchangers. Heat exchangers used for heat transfer, heat recovery, or solar heating shall protect the potable water system from being contaminated by the heat-transfer medium. Single-wall heat exchangers used in indirect-fired water heaters shall meet the requirements of Section 505.4.1. Double-wall heat exchangers shall separate the potable water from the heat-transfer medium by providing a space between the two walls that are vented to the atmosphere. 603.5.5 Water Supply Inlets. Water supply inlets to tanks, vats, sumps, swimming pools, and other receptors shall be protected by one of the following means: (1) An approved air gap. (2) A listed vacuum breaker installed on the discharge

side of the last valve with the critical level not less

(2) A listed vacuum breaker installed on the discharge

side of the last valve with the critical level not less than 6 inches (152 mm) or in accordance with its listing. (3) A backflow preventer suitable for the degree of haz ard, installed in accordance with the requirements

(3) A backflow preventer suitable for the degree of haz ard, installed in accordance with the requirements for that type of device or assembly as set forth in this chapter. 603.5.6 Protection from Lawn Sprinklers and Irri-gation Systems. Potable water supplies to systems having no pumps or connections for pumping equipment, and no chemical injection or provisions for chemical injection, shall be protected from backflow by one of the following devices: (1) Atmospheric vacuum breaker (AVB) (2) Pressure vacuum breaker backflow prevention

assembly (PVB)

(2) Pressure vacuum breaker backflow prevention

assembly (PVB) (3) Spill-resistant pressure vacuum breaker (SVB) (4) Reduced-pressure principle backflow prevention

assembly (RP)

Reduced-pressure principle backflow prevention

assembly (RP) 603.5.6.1 Systems with Pumps. Where sprinkler and irrigation systems have pumps, connections for pumping equipment, or auxiliary air tanks, or are otherwise capable of creating backpressure, the potable water supply shall be protected by the following type of device where the backflow device is located upstream from the source of backpressure: (1) Reduced-pressure principle backflow preven tion assembly (RP)

(1) Reduced-pressure principle backflow preven tion assembly (RP) 603.5.6.2 Systems with Backflow Devices. Where systems have a backflow device installed downstream from a potable water supply pump or a potable water supply pump connection, the device shall be one of the following:

2019 CALIFORNIA PLUMBING CODE 141

WATER SUPPLY AND DISTRIBUTION any other purpose or distributed to any other persons or parti es.

(1) Atmospheric vacuum breaker (AVB) (2) Pressure vacuum breaker backflow prevention

assembly (PVB)

(2) Pressure vacuum breaker backflow prevention

assembly (PVB) (3) Spill-resistant pressure vacuum breaker (SVB) (4) Reduced-pressure principle backflow preven tion assembly (RP)

603.5.12 Beverage Dispensers. Potable water supply to beverage dispensers carbonated beverage dispensers, or coffee machines shall be protected by an air gap or a vented backflow preventer that complies with ASSE 1022. For carbonated beverage dispensers, piping material installed downstream of the backflow preventer shall not be affected by carbon dioxide gas. 603.5.13 Mounted Vacuum Breakers. Deck-Mounted and Deck-mounted or Equipment- equipment-mounted vacuum breakers shall be installed in accordance with their listing and the manufacturer’s installation instructions, with the critical level not less than 1 inch (25.4 mm) above the flood-level rim. 603.5.14 Protection from Fire Systems. Note: Fire Protection Systems has not been adopted by the State Fire Marshal. This section cannot be adopted or enforced pursuant to California Health and Safety Code 13114.7(a), which is being cited for reference. California Health and Safety Code 13114.7. (a) For the purposes of this section the following are

definitions of class I and class II systems:

(4) Reduced-pressure principle backflow preven tion assembly (RP) 603.5.6.3 Systems with Chemical Injectors. Where systems include a chemical injector or provisions for chemical injection, the potable water supply shall be protected by a reduced-pressure principle backflow prevention assembly (RP). 603.5.7 Outlets with Hose Attachments. Potable water outlets with hose attachments, other than water heater drains, boiler drains, and clothes washer connections, shall be protected by a nonremovable hose bibbtype backflow preventer, a nonremovable hose bibb-type vacuum breaker, or by an atmospheric vacuum breaker installed not less than 6 inches (152 mm) above the highest point of usage located on the discharge side of the last valve. In climates where freezing temperatures occur, a listed self-draining frost-proof hose bibb with an integral backflow preventer or vacuum breaker shall be used. 603.5.8 Water-Cooled Equipment. Water-cooled compressors, degreasers, or other water-cooled equipment shall be protected by a backflow preventer installed in accordance with the requirements of this chapter. Water-cooled equipment that produces backpressure shall be equipped with the appropriate protection. 603.5.9 Aspirators. Water inlets to water-supplied aspirators shall be equipped with a vacuum breaker installed in accordance with its listing requirements and this chapter. The discharge shall drain through an air gap. Where the tailpiece of a fixture to receive the discharge of an aspirator is used, the air gap shall be located above the flood-level rim of the fixture. 603.5.10 Steam or Hot Water Boilers. Potable water connections to steam or hot water boilers shall be protected from backflow by a double check valve backflow prevention assembly or reduced pressure principle backflow prevention assembly in accordance with Table 603.2. Where chemicals are introduced into the system a reduced pressure principle backflow prevention assembly shall be provided in accordance with Table 603.2. 603.5.11 Nonpotable Water Piping. In cases where it is impractical to correct individual cross-connections on the domestic waterline, the line supplying such outlets shall be considered a nonpotable water line. No drinking or domestic water outlets shall be connected to the nonpotable waterline. Where possible, portions of the nonpotable waterline shall be exposed, and exposed portions shall be properly identified in a manner satisfactory to the Authority Having Jurisdiction. Each outlet on the nonpotable waterline that is permitted to be used for drinking or domestic purposes shall be posted: “CAUTION: NONPOTABLE WATER, DO NOT DRINK.”

[HCD 1 & HCD 2] An international symbol of a glass in a circle with a slash through it shall be provided sim- ilar to that shown in Figure 601.

(b) Automatic fire sprinkler systems described in subdi-

vision (a) shall not require any backflow protection equipment at the service connection other than required by standards for those systems contained in the publication of the National Fire Protection Association entitled “Installation of Sprinkler Sys- tems” [NFPA Pamphlet No. 13, 1980 edition]. 603.5.15 Health Care or Laboratory Areas. Vacuum breakers for washer-hose bedpans shall be located not less than 5 feet (1524 mm) above the floor. Hose connections in health care or laboratory areas shall be not less than 6 feet (1829 mm) above the floor. 603.5.16 Special Equipment. Portable cleaning equipment and dental vacuum pumps shall be protected from backflow by an air gap, an atmospheric vacuum breaker, a spill-resistant vacuum breaker, or a reduced pressure principle backflow preventer. 603.5.17 Potable Water Outlets and Valves. Potable water outlets, freeze-proof yard hydrants, combination stop-and-waste valves, or other fixtures that incorporate a stop and waste feature that drains into the ground shall not be installed underground.

For the purposes of this section the following are

definitions of class I and class II systems: (1) American Water Works Association [A.W.W.A]

Manual No. M-14 class 1 – Automatic fire

(1) American Water Works Association [A.W.W.A]

Manual No. M-14 class 1 – Automatic fire sprinkler systems with direct connection from public water mains only; no pumps, tanks, or reservoirs; no physical connection from other water supplies; no antifreeze or additives of any kind; and all sprinkler drains discharging to the atmosphere or other safe outlets. (2) American Water Works Association [A.W.W.A]

Manual No. M-14 class 2 – Automatic fire

(2) American Water Works Association [A.W.W.A]

Manual No. M-14 class 2 – Automatic fire sprinkler systems which are the same as class 1, except that booster pumps may be installed in the connections from the street mains. (b) Automatic fire sprinkler systems described in subdi-

vision (a) shall not require any backflow protection

142 2019 CALIFORNIA PLUMBING CODE

WATER SUPPLY AND DISTRIBUTION

603.5.18 Pure Water Process Systems. The water supply to a pure water process system, such as dialysis water systems, semiconductor washing systems, and similar process piping systems, shall be protected from backpressure and backsiphonage by a reduced-pressure principle backflow preventer.

603.5.18.1 Dialysis Water Systems. The individual connections of the dialysis related equipment to the dialysis pure water system shall not require additional backflow protection. 603.5.19 Plumbing Fixture Fittings. Plumbing fixture fittings with integral backflow protection shall comply with ASME A112.18.1/CSA B125.1. 603.5.20 Swimming Pools, Spas, and Hot Tubs. Potable water supply to swimming pools, spas, and hot tubs shall be protected by an air gap or a reduced pressure principle backflow preventer in accordance with the following: (1) The unit is equipped with a submerged fill line. (2) The potable water supply is directly connected to the

ackflow protection shall comply with ASME A112.18.1/CSA B125.1. 603.5.20 Swimming Pools, Spas, and Hot Tubs. Potable water supply to swimming pools, spas, and hot tubs shall be protected by an air gap or a reduced pressure principle backflow preventer in accordance with the following: (1) The unit is equipped with a submerged fill line. (2) The potable water supply is directly connected to the

unit circulation system.

shall authorize by permit the use of CPVC for hot and cold water distribution systems within the interior of res- idential buildings provided all of the following conditions are satisfied: (a) Permit Conditions. Any building permit issued pur-

suant to Section 604.1.1 shall be conditioned on

(a) Permit Conditions. Any building permit issued pur-

suant to Section 604.1.1 shall be conditioned on compliance with the mitigation measures set forth in this section. (b) Approved Materials. Only CPVC plumbing mate-

rial listed as an approved material and installed in

(b) Approved Materials. Only CPVC plumbing mate-

rial listed as an approved material and installed in accordance with this code may be used. (c) Installation and Use. Any installation and use of

CPVC plumbing material pursuant to this section

(c) Installation and Use. Any installation and use of

CPVC plumbing material pursuant to this section shall comply with all applicable requirements of this code and the manufacturer’s installation instructions. (d) Certification of Compliance. Prior to issuing a

building permit pursuant to Section 604.1.1, the

(2) The potable water supply is directly connected to the

unit circulation system. 603.5.21 Chemical Dispensers. The water supply to chemical dispensers shall be protected against backflow. The chemical dispenser shall comply with ASSE 1055 or the water supply shall be protected by one of the following methods: (1) Air gap (2) Atmospheric vacuum breaker (AVB) (3) Pressure vacuum breaker backflow prevention

assembly (PVB)

(d) Certification of Compliance. Prior to issuing a

building permit pursuant to Section 604.1.1, the building official shall require as part of the permit- ting process that the contractor, or the appropriate plumbing subcontractors, provide written certifica- tion: (1) that is required in subdivision (e), and (2) that he or she will comply with the flushing proce- dures and worker safety measures of this code and the manufacturer’s installation instructions. (e) Worker Safety. Any contractor applying for a build-

ing permit that includes the use of CPVC plumbing

(1) They are aware of the health and safety hazards

associated with CPVC plumbing installations; (2) They have included in their Injury and Illness

Prevention Plan the hazards associated with

(3) Pressure vacuum breaker backflow prevention

assembly (PVB) (4) Spill-resistant pressure vacuum breaker (SVB) (5) Reduced-pressure principle backflow prevention

assembly (RP)

Worker Safety. Any contractor applying for a build-

ing permit that includes the use of CPVC plumbing materials authorized pursuant to this section shall include in the permit application a signed written certification stating that: (1) They are aware of the health and safety hazards

associated with CPVC plumbing installations;

(2) They have included in their Injury and Illness

Prevention Plan the hazards associated with CPVC plumbing pipe installations; and (3) The worker safety training elements of their

Injury and Illness Prevention Plan meet the

assembly (RP)

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Contents — California Plumbing Code (Title 24, Part 5)
California Plumbing Code (Title 24, Part 5)
  1. Chapter 1 — GENERAL CODE PROVISIONS
  2. Chapter 2 — DEFINITIONS
  3. Chapter 3 — GENERAL REGULATIONS
  4. Chapter 4 — PLUMBING FIXTURES AND FIXTURE FITTINGS
  5. Chapter 5 — WATER HEATERS
  6. Chapter 6 — WATER SUPPLY AND DISTRIBUTION
    Overview
    1. 601.2 Hot and Cold Water Required. Except where not
    2. 601.3 Identification of a Potable and NonpotableWater System. …
    3. 601.5 [AGR] Meat and Poultry Processing Plants. Except as prov…
    4. 601.4 [CA] Schools of Cosmetology and Cosmeto-
    5. 601.6 [AGR] Collection Centers and Facilities.601.6.1 The wate…
    6. 601.7 [AGR] Renderers. This area shall be provided with
    7. 601.8 [AGR] Horse Meat and Pet Food Establishments.601.8.1 The…
    8. 602.3 Backflow Prevention. No plumbing fixture, device,
    9. 602.4 Approval by Authority. No water piping supplied
    10. 603.0 Cross-Connection Control.603.1 General. Cross-connection…
    11. 603.2 Approval of Devices or Assemblies. Before a
    12. 602.0 Unlawful Connections.602.1 Prohibited Installation. No i…
    13. 602.2 Cross-Contamination. No person shall make a connection o…
    14. 603.3 Backflow Prevention Devices, Assemblies, andMethods. Bac…
    15. 603.4 General Requirements. Assemblies shall comply
    16. 603.5 Specific Requirements. Specific requirements for
    17. 604.0 Materials.604.1 Pipe, Tube, and Fittings. Pipe, tube, fi…
    18. 604.2 Lead Content. The maximum allowable lead content in pipe…
    19. 604.3 Copper or Copper Alloy Tube. Copper or copper
    20. 604.4 Hard-Drawn Copper or Copper Alloy Tubing. Hard-drawn cop…
    21. 604.5 Flexible Connectors. Flexible water connectors
    22. 604.6 Cast-Iron Fittings. Cast-iron fittings up to and
    23. 604.7 Malleable Iron Fittings. Malleable iron water fittings s…
    24. 604.8 Previously Used Piping and Tubing. Piping and
    25. 604.9 Epoxy Coating. The epoxy coating used on existing, under…
    26. 604.10 Plastic Materials. Approved plastic materials shall
    27. 605.0 Joints and Connections.
    28. 604.11 Solder. Solder shall comply with the requirements of
    29. 604.12 Flexible Corrugated Connectors. Flexible corrugated con…
    30. 604.13 Water Heater Connectors. Flexible metallic (copper and …
    31. 605.2 CPVC Plastic Pipe and Joints. CPVC plastic pipe
    32. 605.3 CPVC/AL/CPVC Plastic Pipe and Joints. Chlorinated polyvi…
    33. 605.4 Ductile Iron Pipe and Joints. Ductile iron pipe
    34. 605.5 Galvanized Steel Pipe and Joints. Galvanized
    35. 605.6 PE Plastic Pipe/Tubing and Joints. PE plastic
    36. 605.7 PE-AL-PE Plastic Pipe/Tubing and Joints. PEAL-PE plastic…
    37. 605.8 PE-RT. Polyethylene of raised temperature (PE-RT)
    38. 605.9 PEX Plastic Tubing and Joints. PEX plastic tubing and fi…
    39. 605.11 Polypropylene (PP) Piping and Joints. PP pipe
    40. 605.10 PEX-AL-PEX Plastic Tubing and Joints. PEXAL-PEX plastic…
    41. 605.12 PVC Plastic Pipe and Joints. PVC plastic pipe
    42. 605.13 Stainless Steel Pipe and Joints. Joining methods for st…
    43. 605.14 Slip Joints. In water piping, slip joints shall be perm…
    44. 605.15 Dielectric Unions. Dielectric unions where
    45. 605.16 Joints Between Various Materials. Joints
    46. 606.0 Valves.606.1 General. Valves up to and including 2 inche…
    47. 606.2 Fullway Valve. A fullway valve controlling outlets
    48. 606.3 Multidwelling Units. In multidwelling units, one or
    49. 606.4 Multiple Openings. Valves used to control two or
    50. 606.5 Control Valve. A control valve shall be installed
    51. 606.6 Accessible. Required shutoff or control valves shall
    52. 606.7 Multiple Fixtures. A single control valve shall be
    53. 606.8 [OSHPD 1, 1R, 2, 3, 4 & 5] Each riser or branch
    54. 607.2 Potable Water Tanks. Potable water supply tanks,
    55. 607.3 Venting. Tanks used for potable water shall be tightly
    56. 607.4 Overflow. Tanks shall have not less than a 16 square
    57. 607.5 Valves. Pressurized tanks shall be provided with a
    58. 608.0 Water Pressure, Pressure Regulators, Pres-
    59. 608.2 Excessive Water Pressure. Where static water
    60. 608.3 Expansion Tanks, and Combination Tempera-ture and Pressu…
    61. 608.4 Pressure Relief Valves. Each pressure relief valve
    62. 608.5 Discharge Piping. The discharge piping serving a
    63. 609.3 Under Concrete Slab. Water piping installed within
    64. 608.6 Water-Heating Devices. A water-heating device
    65. 608.7 Vacuum Relief Valves. Where a hot-water storage
    66. 609.0 Installation, Testing, Unions, and Location.609.1 Instal…
    67. 609.2 Trenches. Water pipes shall not be run or laid in the
    68. 609.4 Testing. Upon completion of a section or of the entire
    69. 609.5 Unions. Unions shall be installed in the water supply
    70. 609.6 Location. Except as provided in Section 609.7, no
    71. 609.7 Abutting Lot. Nothing contained in this code shall
    72. 609.8 Low-Pressure Cutoff Required on BoosterPumps for Water D…
    73. 609.9 Disinfection of Potable Water System. New or
    74. 609.11 Pipe Insulation. Insulation of domestic hot water
    75. 610.2 Pressure Loss. Where a water filter, water softener,
    76. 609.10 Water Hammer. [Not adopted by HCD] Building water suppl…
    77. 610.3 Quantity of Water. The quantity of water required
    78. 610.4 Sizing Water Supply and Distribution Systems. Systems wi…
    79. 610.5 Sizing per Appendices A and C. Except as provided in Sec…
    80. 610.6 Friction and Pressure Loss. Except where the type
    81. 610.7 Conditions for Using Table 610.4. On a proposed
    82. 610.9 Size of Branches. Where Table 610.4 is used, the minimum…
    83. 610.10 Sizing for Flushometer Valves. Where using
    84. 610.8 Size of Meter and Building Supply Pipe UsingTable 610.4.…
    85. 610.13 Exceptions. The provisions of this section relative
    86. 610.12 Sizing for Velocity. Water piping systems shall not
    87. 610.11 Sizing Systems for Flushometer Tanks. The
    88. 611.2 Air Gap Discharge. Discharge from drinking water
    89. 611.3 Connection Tubing. The tubing to and from drinking water…
    90. 611.4 Sizing of Residential Softeners. Residential-use
    91. 612.0 Residential Fire Sprinkler Systems.612.1 Where Required.…
    92. 612.2 Types of Systems. This section shall apply to standalone…
    93. 612.3 Sprinklers. Sprinklers shall be installed in accordance …
    94. 612.4 Sprinkler Piping System. Sprinkler piping systems
    95. 612.5 Sprinkler Piping Design. Sprinkler piping systems
    96. 612.6 Instructions and Signs. An owner’s manual for the
    97. 612.7 Inspection and Testing. The inspection and testing of sp…
    98. 613.0 [OSHPD 1, 1R, 2, 3, 4 & 5] Domestic Hot-Water
    99. 613.2 At least two pieces of hot-water-heating equipment shall
    100. 613.3 Instantaneous heaters are permitted for supplying hot
    101. 613.4 Water storage tanks shall be fabricated of corrosion-
    102. 613.5 Temperature control valves shall be provided to auto-
    103. 613.6 Hot-water distribution system serving patient care
    104. 613.7 At fixtures where water exceeding 125°F (52°C) is acces-
    105. 613.8 Sectionalizing valves shall be provided as required by
    106. 614.2 All piping for multistation or central dialysis units sh…
    107. 614.3 All valves shall be located in accessible locations.
    108. 614.4 Piping and valves shall be identified according to their
    109. 614.5 A means of preventing backwashing or flushing of the
    110. 614.6 A continuous audible alarm shall sound at the nurses’
    111. 614.7 Water used for dialysis treatment shall meet the latest
    112. 614.8 A diagram of all piping as installed shall be posted at …
    113. 615.1 Uses Not Permitted.615.1.1 [OSHPD 1, 1R, 2, 3, 4 & 5] No…
    114. 615.2 [OSHPD 1, 1R, 2, 3, 4 & 5] Non-potable water sys-
    115. 615.3 [OSHPD 1, 1R, 2, 3, 4 & 5] Outlets for non-potable
    116. 615.4 [OSHPD 1] Emergency Water Supply.615.4.1 For new acute c…
  7. Chapter 7 — SANITARY DRAINAGE
  8. Chapter 8 — INDIRECT WASTES
  9. Chapter 9 — VENTS
  10. Chapter 10 — TRAPS AND INTERCEPTORS
  11. Chapter 11 — STORM DRAINAGE
  12. Chapter 12 — FUEL GAS PIPING
  13. Chapter 13 — HEALTH CARE FACILITIES AND MEDICAL GAS AND MEDICA…
  14. Chapter 14 — FIRESTOP PROTECTION
  15. Chapter 15 — ALTERNATE WATER SOURCES FOR NONPOTABLE APPLICATIONS
  16. Chapter 16 — NONPOTABLE RAINWATER CATCHMENT SYSTEMS
  17. Chapter 17 — REFERENCED STANDARDS
  18. Appendix A — RECOMMENDED RULES FOR SIZING THE WATER SUPPLY SYS…
  19. Appendix B — EXPLANATORY NOTES ON COMBINATION WASTE AND VENT S…
  20. Appendix C — ALTERNATE PLUMBING SYSTEMS
  21. Appendix D — SIZING STORM WATER DRAINAGE SYSTEMS
  22. Appendix E — MANUFACTURED/MOBILE HOME PARKS AND RECREATIONAL V…
  23. Appendix F — FIREFIGHTER BREATHING AIR REPLENISHMENT SYSTEMS
  24. Appendix G — SIZING OF VENTING SYSTEMS
  25. Appendix H — PRIVATE SEWAGE DISPOSAL SYSTEMS
  26. Appendix I — INSTALLATION STANDARD FOR PEX TUBING SYSTEMS FOR …
  27. Appendix J — COMBINATION OF INDOOR AND OUTDOOR COMBUSTION AND …
  28. Appendix K — POTABLE RAINWATER CATCHMENT SYSTEMS
  29. Appendix L — SUSTAINABLE PRACTICES
  30. Appendix M — PEAK WATER DEMAND CALCULATOR

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