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Chapter 6 — WATER SUPPLY AND DISTRIBUTION

603.4 General Requirements. Assemblies shall comply

California Plumbing Code (Title 24, Part 5) · 2022 edition · updated 2026-09-10 · California

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

with listed standards and be acceptable to the Authority Having Jurisdiction, with jurisdiction over the selection and installation of backflow prevention assemblies.

603.4.1 Backflow Prevention Valve. Where more than one backflow prevention valve is installed on a single premise, and the valves are installed in one location, each separate valve shall be permanently identified by the permittee in a manner satisfactory to the Authority Having Jurisdiction. 603.4.2 Testing. The premise owner or responsible person shall have the backflow prevention assembly tested by a certified backflow assembly tester at the time of installation, repair, or relocation and not less than on an annual schedule thereafter, or more often where required by the Authority Having Jurisdiction. The periodic testing shall be performed in accordance with the procedures referenced in ASSE Series 5000 by a tester qualified in accordance with those standards. The field test kit used shall comply with ASSE 1064. 603.4.3 Access and Clearance. Access and clearance shall be provided for the required testing, maintenance, and repair. Access and clearance shall be in accordance with the manufacturer’s instructions, and not less than 12 inches (305 mm) between the lowest portion of the assembly and grade, floor, or platform. Installations elevated that exceed 5 feet (1524 mm) above the floor or grade shall be provided with a platform capable of supporting a tester or maintenance person. 603.4.4 Connections. Direct connections between potable water piping and sewer-connected wastes shall not be permitted to exist un der any condition with or without backflow protection. Where potable water is discharged to the drainage system, it shall be by means of an approved air gap of two pipe diameters of the supply inlet, but in no case shall the gap be less than 1 inch (25.4 mm). Connection shall be permitted to be made to the inlet side of a trap provided that an approved vacuum breaker is installed not less than 6 inches (152 mm), or the distance according to the device’s listing, above the flood-level rim of such trapped fixture, so that at no time will such device be subjected to backpressure. 603.4.5 Hot Water Backflow Preventers. Backflow preventers for hot water exceeding 110°F (43°C) shall be a type designed to operate at temperatures exceeding 110°F (43°C) without rendering a portion of the assembly inoperative.

WATER SUPPLY AND DISTRIBUTION

603.4.6 Integral Backflow Preventers. Fixtures, appliances, or appurtenances with integral backflow preventers or integral air gaps manufactured as a unit shall be installed in accordance with their listing requirements and the manufacturer’s installation instructions. 603.4.7 Freeze Protection. In cold climate areas, backflow assemblies and devices shall be protected from freezing with an outdoor enclosure that complies with ASSE 1060 or by a method acceptable to the Authority Having Jurisdiction. 603.4.8 Drain Lines. Drain lines serving backflow devices or assemblies shall be sized in accordance with the discharge rates of the manufacturer’s flow charts of such devices or assemblies. 603.4.9 Prohibited Locations. Backflow prevention devices with atmospheric vents or ports shall not be installed in pits, underground, or submerged locations. Backflow preventers shall not be located in an area containing fumes that are toxic, poisonous, or corrosive.

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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. 601.1 Applicability. This chapter shall govern the materials,
    2. 601.2 Water Supply and Flushing. Each plumbing fixture shall b…
    3. 601.3 Identification of a Potable and Nonpotable
    4. 601.4 [CA] Schools of Cosmetology and Cosmeto-
    5. 601.5 [AGR] Meat and Poultry Processing Plants.
    6. 601.6 [AGR] Collection Centers and Facilities.
    7. 601.7 [AGR] Renderers. This area shall be provided with
    8. 601.8 [AGR] Horse Meat and Pet Food Establishments.
    9. 602.1 Prohibited Installation. No installation of potable
    10. 602.2 Cross-Contamination. No person shall make a connection o…
    11. 602.3 Backflow Prevention. No plumbing fixture, device,
    12. 602.4 Approval by Authority. No water piping supplied
    13. 603.1 General. Cross-connection control shall be provided
    14. 603.2 Approval of Devices or Assemblies. Before a
    15. 603.3 Backflow Prevention Devices, Assemblies, and
    16. 603.4 General Requirements. Assemblies shall comply
    17. 603.5 Specific Requirements. Specific requirements for
    18. 604.1 Pipe, Tube, and Fittings. Pipe, tube, fittings, solvent …
    19. 604.2 Lead Content. The maximum allowable lead content in pipe…
    20. 604.3 Copper or Copper Alloy Tube. Copper or copper
    21. 604.4 Hard-Drawn Copper or Copper Alloy Tubing.
    22. 604.5 Flexible Connectors. Flexible water connectors
    23. 604.6 Cast-Iron Fittings. Cast-iron fittings up to and
    24. 604.7 Malleable Iron Fittings. Malleable iron water fittings s…
    25. 604.8 Previously Used Piping and Tubing. Piping and
    26. 604.9 Epoxy Coating. The epoxy coating used on existing, under…
    27. 604.10 Plastic Materials. Approved plastic materials shall
    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. 605.1 Copper or Copper Alloy Pipe, Tubing, and
    32. 605.2 CPVC Plastic Pipe and Joints. CPVC plastic pipe
    33. 605.3 CPVC/AL/CPVC Plastic Pipe and Joints. Chlorinated polyvi…
    34. 605.4 Ductile Iron Pipe and Joints. Ductile iron pipe
    35. 605.5 Galvanized Steel Pipe and Joints. Galvanized
    36. 605.6 PE Plastic Pipe/Tubing and Joints. PE plastic
    37. 605.7 PE-AL-PE Plastic Pipe/Tubing and Joints. PEAL-PE plastic…
    38. 605.8 PE-RT. Polyethylene of raised temperature (PE-RT)
    39. 605.9 PEX Plastic Tubing and Joints. PEX plastic tubing and fi…
    40. 605.10 PEX-AL-PEX Plastic Tubing and Joints. PEXAL-PEX plastic…
    41. 605.11 Polypropylene (PP) Piping and Joints. PP pipe
    42. 605.12 PVC Plastic Pipe and Joints. PVC plastic pipe
    43. 605.13 Stainless Steel Pipe and Joints. Joining methods for st…
    44. 605.14 Slip Joints. In water piping, slip joints shall be perm…
    45. 605.15 Dielectric Unions. Dielectric unions where
    46. 605.16 Joints Between Various Materials. Joints
    47. 606.1 General. Valves up to and including 2 inches (50
    48. 606.2 Fullway Valve. A fullway valve controlling outlets
    49. 606.3 Multidwelling Units. In multidwelling units, one or
    50. 606.4 Multiple Openings. Valves used to control two or
    51. 606.5 Control Valve. A control valve shall be installed
    52. 606.6 Accessible. Required shutoff or control valves shall
    53. 606.7 Multiple Fixtures. A single control valve shall be
    54. 606.8 [OSHPD 1, 1R, 2, 3, 4 & 5] Each riser or branch
    55. 606.9 Check Valve Required. All systems that circulate
    56. 606.10 Leak Detection Devices. Where leak detection
    57. 607.1 General. Potable water supply tanks shall be installed
    58. 607.2 Potable Water Tanks. Potable water supply tanks,
    59. 607.3 Venting. Tanks used for potable water shall be tightly
    60. 607.4 Overflow. Tanks shall have not less than a 16 square
    61. 607.5 Valves. Pressurized tanks shall be provided with a
    62. 608.1 Inadequate Water Pressure. Where the water pressure in t…
    63. 608.2 Excessive Water Pressure. Where static water
    64. 608.3 Expansion Tanks, and Combination Tempera-
    65. 608.4 Pressure Relief Valves. Each pressure relief valve
    66. 608.5 Discharge Piping. The discharge piping serving a
    67. 608.6 Water-Heating Devices. A water-heating device
    68. 608.7 Vacuum Relief Valves. Where a hot-water storage
    69. 609.1 Installation. Water piping shall be adequately supported…
    70. 609.2 Trenches. Water pipes shall not be run or laid in the
    71. 609.3 Under Concrete Slab. Water piping installed within
    72. 609.4 Testing. Upon completion of a section or of the entire
    73. 609.5 Unions. Unions shall be installed in the water supply
    74. 609.6 Location. Except as provided in Section 609.7, no
    75. 609.7 Abutting Lot. Nothing contained in this code shall
    76. 609.8 Pumps. Pumps shall be installed in accordance with
    77. 609.9 Low-Pressure Cutoff Required on Booster
    78. 609.10 Disinfection of Potable Water System. New or
    79. 609.11 Water Hammer. [Not adopted by HCD] Building
    80. 609.12 Pipe Insulation. Insulation of domestic hot water
    81. 610.1 Size. The size of each water meter and each potable
    82. 610.2 Pressure Loss. Where a water filter, water softener,
    83. 610.3 Quantity of Water. The quantity of water required to
    84. 610.4 Sizing Water Supply and Distribution Systems.
    85. 610.5 Sizing per Appendices A and C. Except as provided in Sec…
    86. 610.6 Friction and Pressure Loss. Except where the type
    87. 610.7 Conditions for Using Table 610.4. On a proposed
    88. 610.8 Size of Meter and Building Supply Pipe Using
    89. 610.9 Size of Branches. Where Table 610.4 is used, the
    90. 610.10 Sizing for Flushometer Valves. Where using
    91. 610.11 Sizing Systems for Flushometer Tanks. The size
    92. 610.12 Sizing for Velocity. Water piping systems shall not
    93. 610.13 Exceptions. The provisions of this section relative
    94. 611.1 Application. Drinking water treatment units shall
    95. 611.2 Air Gap Discharge. Discharge from drinking water
    96. 611.3 Connection Tubing. The tubing to and from drinking water…
    97. 611.4 Sizing of Residential Softeners. Residential-use
    98. 612.1 Installation. Residential Sprinkler Systems shall be
    99. 613.1 The domestic water-heating equipment and distribu-
    100. 613.2 At least two pieces of hot-water-heating equipment shall
    101. 613.3 Instantaneous heaters are permitted for supplying hot
    102. 613.4 Water storage tanks shall be fabricated of corrosion-
    103. 613.5 Temperature control valves shall be provided to auto-
    104. 613.6 Hot-water distribution system serving patient care
    105. 613.7 At fixtures where water exceeding 125°F (52°C) is acces-
    106. 613.8 Sectionalizing valves shall be provided as required by
    107. 614.1 [OSHPD 1, 1R, 2, 3, 4 & 5] Dialysis water feedlines
    108. 614.2 All piping for multistation or central dialysis units sh…
    109. 614.3 All valves shall be located in accessible locations.
    110. 614.4 Piping and valves shall be identified according to their
    111. 614.5 A means of preventing backwashing or flushing of the
    112. 614.6 A continuous audible alarm shall sound at the nurses’
    113. 614.7 Water used for dialysis treatment shall meet the latest
    114. 614.8 A diagram of all piping as installed shall be posted at …
    115. 615.1 Uses Not Permitted.
    116. 615.2 [OSHPD 1, 1R, 2, 3, 4 & 5] Non-potable water sys-
    117. 615.3 [OSHPD 1, 1R, 2, 3, 4 & 5] Outlets for non-potable
    118. 615.4 [OSHPD 1] Emergency Water Supply.
  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 STANDARDS
  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
  31. Appendix N — IMPACT OF WATER TEMPERATURE ON THE POTENTIAL FOR …

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