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Earlier editions: 20222019

Chapter 6 — WATER SUPPLY AND DISTRIBUTION

612.1 Installation. Residential Sprinkler Systems shall be

California Plumbing Code (Title 24, Part 5) · 2025 edition · updated 2026-09-10 · California

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

installed in compliance with the California Residential Code or the California Fire Code.

160 2025 CALIFORNIA PLUMBING CODE

WATER SUPPLY AND DISTRIBUTION

TABLE 611.1 DRINKING WATER TREATMENT UNITS
APPLICATION RESIDENTIAL RESIDENTIAL COMMERCIAL
APPLICATION POINT OF USE POINT OF ENTRY POINT OF ENTRY
Aesthetic Contaminant
Reduction (filters)		 NSF/ANSI 42 NSF/ANSI 42 ASSE 1087 and NSF/ANSI 42*
Health Related Contaminant
Reduction (filters)		 NSF/ANSI 53 NSF/ANSI 53 ASSE 1087 and NSF/ANSI 53*
Water Softener – NSF/ANSI 44 ASSE 1087
Ultraviolet Water Treatment NSF/ANSI 55 NSF/ANSI 55 ASSE 1087
Reverse Osmosis NSF/ANSI 58 NSF/ANSI/CAN 61 ASSE 1087
Distillation NSF/ANSI 62 NSF/ANSI 62 ASSE 1087 
 - Required for commercial modular systems only.

TABLE 611.4 SIZING OF RESIDENTIAL WATER SOFTENERS [4]

REQUIRED SIZE OF
SOFTENER CONNECTION
(inches)		 NUMBER OF BATHROOM
GROUPS SERVED1

3⁄4		 up to 22


1		 up to 43

For SI units: 1 inch = 25 mm

Notes: 1 Installation of a kitchen sink and dishwasher, laundry sink, and automatic clothes washer permitted without additional size increase. 2 An additional water closet and lavatory permitted. 3 Over four bathroom groups, the softener size shall be engineered for the specific installation. 4 See also Appendix A, Recommended Rules for Sizing the Water Supply System, and Appendix C, Alternate Plumbing Systems, for alternate methods of sizing water supply systems.

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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 Schools of Cosmetology and Cosmetological
    5. 601.5 Meat and Poultry Processing Plants. [AGR]
    6. 601.6 Collection Centers and Facilities. [AGR]
    7. 601.7 Renderers. [AGR] This area shall be provided with
    8. 601.8 Horse Meat and Pet Food Establishments. [AGR]
    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
    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 installed
    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 in
    58. 607.2 Private Well Water Tanks. Pressurized potable water
    59. 607.3 Potable Water Tanks. Potable water supply tanks,
    60. 607.4 Venting. Tanks used for potable water shall be tightly
    61. 607.5 Overflow. Tanks shall have not less than a 16 square
    62. 607.6 Valves. Pressurized tanks shall be provided with a listed
    63. 608.1 Inadequate Water Pressure. Where the water pressure in t…
    64. 608.2 Excessive Water Pressure. Where static water
    65. 608.3 Expansion Tanks, and Combination Tempera-
    66. 608.4 Pressure Relief Valves. Each pressure relief valve
    67. 608.5 Discharge Piping. The discharge piping serving a
    68. 608.6 Water-Heating Devices. A water-heating device
    69. 608.7 Vacuum Relief Valves. Where a hot-water storage
    70. 609.1 Installation. Water piping shall be adequately supported…
    71. 609.2 Trenches. Water pipes shall not be run or laid in the
    72. 609.3 Under Concrete Slab. Water piping installed within
    73. 609.4 Testing. Upon completion of a section or of the entire
    74. 609.5 Unions. Unions shall be installed in the water supply
    75. 609.6 Location. Except as provided in Section 609.7, no
    76. 609.7 Abutting Lot. Nothing contained in this code shall
    77. 609.8 Pumps. Pumps shall be installed in accordance with
    78. 609.9 Low-Pressure Cutoff Required on Booster
    79. 609.10 Disinfection of Potable Water System. New or
    80. 609.11 Water Hammer. [Not adopted by HCD] Building
    81. 609.12 Pipe Insulation. Insulation of domestic hot water
    82. 610.1 Size. The size of each water meter and each potable
    83. 610.2 Pressure Loss. Where a water filter, water softener,
    84. 610.3 Quantity of Water. The quantity of water required to be
    85. 610.4 Sizing Water Supply and Distribution Systems.
    86. 610.5 Sizing per Appendices A, C, and M . Except as
    87. 610.6 Friction and Pressure Loss. Except where the type
    88. 610.7 Conditions for Using Table 610.4. On a proposed
    89. 610.8 Size of Meter and Building Supply Pipe Using
    90. 610.9 Size of Branches. Where Table 610.4 is used, the minimum…
    91. 610.10 Sizing for Flushometer Valves. Where using
    92. 610.11 Sizing Systems for Flushometer Tanks. The size
    93. 610.12 Sizing for Velocity. Water piping systems shall not
    94. 610.13 Exceptions. The provisions of this section relative
    95. 611.1 Application. Drinking water treatment units shall
    96. 611.2 Air Gap Discharge. Discharge from drinking water
    97. 611.3 Connection Tubing. The tubing to and from drinking water…
    98. 611.4 Sizing of Residential Softeners. Residential-use
    99. 612.1 Installation. Residential Sprinkler Systems shall be
    100. 613.1 The domestic water-heating equipment and distribu-
    101. 613.2 At least two pieces of hot-water-heating equipment shall
    102. 613.3 Instantaneous heaters are permitted for supplying hot
    103. 613.4 Water storage tanks shall be fabricated of corrosion-
    104. 613.5 Temperature control valves shall be provided to auto-
    105. 613.6 Hot-water distribution system serving patient care areas
    106. 613.7 At fixtures where water exceeding 125°F (52°C) is acces-
    107. 613.8 Sectionalizing valves shall be provided as required by
    108. 613.9 Hot water distribution shall include test ports and valved
    109. 614.1 Dialysis water feedlines shall be CPVC (chlorinated
    110. 614.2 All piping for multistation or central dialysis units sh…
    111. 614.3 All valves shall be located in accessible locations.
    112. 614.4 Piping and valves shall be identified according to their
    113. 614.5 A means of preventing backwashing or flushing of the
    114. 614.6 A continuous audible alarm shall sound at the nurses’
    115. 614.7 Water treatment equipment and water used for dialysis
    116. 614.8 A diagram of all piping as installed shall be posted at …
    117. 615.1 Uses Not Permitted.
    118. 615.2 [OSHPD 1, 1R, 2, 3, 4 & 5] Non-potable water sys-
    119. 615.3 [OSHPD 1, 1R, 2, 3, 4 & 5] Outlets for non-potable
    120. 616.1 For new acute care hospital buildings submitted after
    121. 616.2 The emergency supply of water shall be provided at ade-
    122. 616.3 Storage tank connections and circulation shall be
  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 …
  32. Appendix O — NON-SEWERED SANITATION SYSTEMS
  33. Appendix P — PROFESSIONAL QUALIFICATIONS
  34. Appendix Q — INDOOR HORTICULTURAL FACILITIES
  35. Appendix R — TINY HOUSES
  36. Appendix S — ONSITE STORMWATER TREATMENT SYSTEMS

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