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Earlier editions: 20222019

Chapter 15 — ALTERNATE WATER SOURCES FOR NONPOTABLE APPLICATIONS

1505.1 General. The provisions of Section 1505.0 through

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.

Section 1505.16 shall apply to safely plumb buildings with both potable and recycled water supply systems. Unless otherwise specified in this code, the general provisions applying to alter- nate water systems pursuant to Section 1501.0 through Section 1501.10 and Section 1502.4 through Section 1502.6 shall apply to recycled water supply systems. The provisions in this section encompass the installation, construction, alteration, and repair of recycled water supply systems that are within or a part of a building, including a landscape irrigation system that connects to plumbing that is within or a part of a building, and receive reclaimed (recycled) water provided by a water/wastewater util- ity. When dealing with recycled water supply systems, the Authority Having Jurisdiction and Enforcing Agency may include the recycled water purveyor or potable water purveyor in accordance with their respective statutory authority and responsibility as provided on their respective permits for sup- plying water. Plumbing systems using reclaimed (recycled) water that do not enter the interior of a building plumbed with potable water are not encompassed by this section. All reclaimed (recycled) water use, covered and not covered by this code, is subject to applicable provisions of the State Water Resources Control Board’s Cross-Connection Control Policy Handbook and the California Code of Regulations: Title 22 and Title 23 .

1505.1.1 Allowed Uses. Allowed uses shall include water closets, urinals, trap primers for floor drains and floor sinks, aboveground and subsurface irrigation, industrial or commercial cooling or air conditioning and other uses as generally allowed in the California Code of Regulations, Title 22, Division 4, Chapter 3 and specifi- cally allowed in the permit for the facility producing or supplying the reclaimed (recycled) water issued by the State Water Resources Control Board or Regional Water Quality Control Board .

1505.1.2 Structures Allowed for Toilet and Urinal Flushing. In accordance with Water Code Section 13553, reclaimed (recycled) water shall be allowed for toilet and urinal flushing in certain structures. These structures include commercial, retail, and office buildings, theaters, auditoriums, condominium projects, schools, hotels, apart-

318 2025 CALIFORNIA PLUMBING CODE

ALTERNATE WATER SOURCES FOR NONPOTABLE APPLICATIONS

ments, barracks, dormitories, jails, prisons, reformatories, and other structures as determined by the State Water Resources Control Board.

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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
  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
    Overview
    1. 1501.1 Applicability. [BSC-CG, DWR & HCD 1] The provisions of …
    2. 1501.2 System Design. [BSC-CG, HCD 1 & DWR]
    3. 1501.3 Permit. [BSC-CG, HCD 1 & DWR] It shall be
    4. 1501.4 Component Identification. System components
    5. 1501.5 Maintenance and Inspection. [BSC-CG, HCD
    6. 1505.16 .
    7. 1501.6 Operation and Maintenance Manual. [BSC-
    8. 1501.7 Minimum Water Quality Requirements. [BSC-
    9. 1501.8 Material Compatibility. Alternate water source systems …
    10. 1501.9 Signage. [BSC-CG, HCD 1, HCD 2 & HCD 1-
    11. 1501.10 System Controls. Controls for pumps, valves, and
    12. 1502.1 General. Alternate water source systems shall be
    13. 1502.2 Supply System Inspection and Test. Alternate
    14. 1502.3 Cross-Connection Inspection and Testing. An
    15. 1502.4 Separation Requirements. Underground alternate
    16. 1502.5 Abandonment. Alternate water source systems that
    17. 1502.6 Sizing. Unless otherwise provided for in this chapter, …
    18. 1503.1 General. The provisions of this section shall apply to
    19. 1503.2 System Requirements. Gray water shall be permitted to b…
    20. 1503.3 Connections to Potable and Reclaimed (Recy-
    21. 1503.4 Location. No gray water system or part thereof shall
    22. 1503.5 Plot Plan Submission. No permit for a gray water
    23. 1503.6 Prohibited Location. Where there is insufficient
    24. 1503.7 Drawings and Specifications. The Authority Having Juris…
    25. 1503.8 Procedure for Estimating Gray Water Dis-
    26. 1503.9 Gray Water System Components. Gray water
    27. 1504.1 General. Irrigation or disposal fields shall be permitt…
    28. 1504.2 Required Area of Subsurface Irrigation
    29. 1504.3 Determination of Maximum Absorption
    30. 1504.4 Groundwater Level. No excavation for an irrigation fiel…
    31. 1504.5 Irrigation, Disposal Field and Mulch Basin
    32. 1504.6 Reserved.
    33. 1504.7 Reserved .
    34. 1504.8 Gray Water System Color and Marking Infor-
    35. 1504.9 Other Collection and Distribution Systems.
    36. 1504.10 Testing. Building drains and vents for gray water
    37. 1504.11 Maintenance. Gray water systems and components shall b…
    38. 1505.1 General. The provisions of Section 1505.0 through
    39. 1505.2 Permit. It shall be unlawful for a person to construct,
    40. 1505.3 System Changes. No changes or connections shall
    41. 1505.4 Connections to Potable or Recycled Water
    42. 1505.5 Water Pressure. Reclaimed (recycled) water systems supp…
    43. 1505.6 Initial Cross-Connection Test. A cross-connection
    44. 1505.7 Recycled Water Supply System Materials.
    45. 1505.8 Recycled Water Supply System Color and
    46. 1505.9 Valves. Valves, except fixture supply control valves,
    47. 1505.13 Signage . Signs in rooms and water closet tanks in
    48. 1505.14 Inspection and Testing. Recycled water supply
    49. 1505.10 Hose Bibbs. Hose bibbs shall not be allowed on
    50. 1505.11 Required Appurtenances. The recycled water
    51. 1505.12 Pipe Separation in Trenches . Reclaimed (recycled) wat…
    52. 1505.15 Minimum Water Quality Requirements for
    53. 1505.16 Maintenance and Inspection. Recycled water
    54. 1506.1 General. The provisions of this section shall apply
    55. 1506.2 Plumbing Plan Submission. No permit for an
    56. 1506.3 System Changes. No changes or connections shall
    57. 1506.4 Connections to Potable or Recycled Water
    58. 1506.5 Water Pressure. On-site treated non-potable gray
    59. 1506.11 Valves. Valves, except fixture supply control
    60. 1506.12 Signs. Signs in buildings using on-site treated nonpot…
    61. 1506.13 Inspection and Testing. On-site treated nonpotable gra…
    62. 1506.6 Initial Cross-Connection Test. A cross-connection test …
    63. 1506.7 On-Site Treated Nonpotable Gray Water Sys-
    64. 1506.8 On-Site Treated Nonpotable Gray Water
    65. 1506.9 On-Site Treated Nonpotable Gray Water Sys-
    66. 1506.10 Design and Installation. The design and installation o…
  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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