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Chapter 15 — ALTERNATE WATER SOURCES FOR NONPOTABLE APPLICATIONS

1503.2 System Requirements.

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.

Gray water shall be permitted to be diverted away from a sewer or private sewage disposal system, and discharge to a subsurface irrigation or subsoil irrigation system , or disposal field . The gray water shall be permitted to discharge to a mulch basin for residen- tial occupancies . Gray water shall not be used to irrigate root crops or food crops intended for human consumption that comes in contact with soil.

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(10)Gray water shall not contain hazardous chemicals

derived from activities such as cleaning car parts, washing greasy or oily rags, or disposing of waste solutions from home photo labs or similar hobbyist or home occupational activities. (11) Exemption from construction permit requirements of

this code shall not be deemed to grant authorization

(11) Exemption from construction permit requirements of

this code shall not be deemed to grant authorization for any gray water system to be installed in a man- ner that violates other provisions of this code or any other laws or ordinances of the enforcing agency. (12)An operation and maintenance manual shall be pro-

vided to the owner. Directions shall indicate that the

(12)An operation and maintenance manual shall be pro-

vided to the owner. Directions shall indicate that the manual is to remain with the building throughout the life of the system and upon change of ownership or occupancy.

1503.2.1 Surge Capacity. Gray water systems shall be designed to have the capacity to accommodate peak flow rates and distribute the total amount of estimated gray water on a daily basis to a subsurface irrigation field, subsoil irrigation field , disposal field, or mulch basin without surfacing, ponding, or runoff. A surge tank is required for systems that are unable to accommodate peak flow rates and distribute the total amount of gray water by gravity drainage. The water discharge for gray water systems shall be determined in accordance with Section 1503.8.1 or Section 1503.8.2. Exception: It is not the intent of this section to require that all gray water must be handled by an irrigation field or disposal field. It is acceptable for excess gray water to be diverted to the building sewer through a diverter valve or overflow drain as permitted in this chapter.

2019 CALIFORNIA PLUMBING CODE 313

ALTERNATE WATER SOURCES FOR NONPOTABLE APPLICATIONS any other purpose or distributed to any other persons or parties.

1503.2.2 Diversion. The gray water system shall connect to the sanitary drainage system downstream of fixture traps and vent connections through an approved diverter valve. The diverter valve shall be installed in a readily accessible location and clearly indicate the direction of flow. Exception: [HCD 1] A clothes washer system in com- pliance with Section 1503.1.1. 1503.2.3 Backwater Valves. Gray water drains subject to backflow shall be provided with a backwater valve at the point of connection to the building sewer system, so located as to be accessible for inspection and maintenance.

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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. 1501.0 General.1501.1 Applicability [BSC-CG, DWR & HCD 1]. The
    2. 1501.2 System Design. Alternate water source systems
    3. 1501.3 Permit [BSC-CG, HCD 1, DWR]. It shall be unlawful for a…
    4. 1501.4 Component Identification. System components
    5. 1501.5 Maintenance and Inspection 1, DWR]. Alternate water sou…
    6. 1501.6 Operation and Maintenance Manual [BSC-
    7. 1501.7 Minimum Water Quality Requirements [BSC-
    8. 1501.8 Material Compatibility. Alternate water source systems …
    9. 1501.9 Signage [BSC-CG, HCD 1, HCD 2, HCD 1-AC, &DWR]. Signage…
    10. 1501.10 System Controls. Controls for pumps, valves, and
    11. 1501.11 Hose Bibbs for Single-Family Dwellings [HCD1]. Hose bi…
    12. 1502.2 Supply System Inspection and Test. Alternate
    13. 1502.3 Cross-Connection Inspection and Testing. An
    14. 1502.6 Sizing. Unless otherwise provided for in this chapter, …
    15. 1503.1 General. The provisions of this section shall apply
    16. 1502.4 Separation Requirements. Underground alternate
    17. 1502.5 Abandonment. Alternate water source systems that
    18. 1503.2 System Requirements. Gray water shall be permitted to b…
    19. 1503.3 Connections to Potable and Reclaimed(Recycled) Water Sy…
    20. 1503.4 Location. No gray water system or part thereof shall
    21. 1503.5 Plot Plan Submission. No permit for a gray water
    22. 1503.6 Prohibited Location. Where there is insufficient
    23. 1503.7 Drawings and Specifications. The Authority
    24. 1503.9 Gray Water System Components. Gray water
    25. 1504.2 Required Area of Subsurface Irrigation
    26. 1504.3 Determination of Maximum Absorption Capac-
    27. 1504.4 Groundwater Level. No excavation for an irrigation fiel…
    28. 1504.5 Irrigation, Disposal Field and Mulch Basin Con-structio…
    29. 1504.6 Reserved.
    30. 1504.7 Reserved.
    31. 1504.8 Gray Water System Color and Marking Infor-mation. Press…
    32. 1504.9 Other Collection and Distribution Systems. Other collec…
    33. 1504.10 Testing. Building drains and vents for gray water
    34. 1504.11 Maintenance. Gray water systems and components shall b…
    35. 1505.0 Recycled Water 1505.1 General. The provisions of Supply…
    36. 1505.3 System Changes. No changes or connections shall
    37. 1505.4 Connections to Potable or Reclaimed (Recy-cled) Water S…
    38. 1505.2 Permit. It shall be unlawful for a person to construct,
    39. 1505.5 Initial Cross-Connection Test. A cross-connection test …
    40. 1505.6 Recycled Water Recycled water supply system materials s…
    41. 1505.8 Valves. Valves, except fixture supply control valves,
    42. 1505.9 Hose Bibbs. Hose bibbs shall not be allowed on
    43. 1505.10 Required Appurtenances. The recycled water
    44. 1505.11 Pipe Separation in Trenches. Reclaimed (recycled) wate…
    45. 1505.12 Signage. Signs in rooms and water closet tanks in
    46. 1505.13 Inspection and Testing. Recycled water supply
    47. 1505.15 Maintenance and Inspection. Recycled water
    48. 1506.0 On-Site Treated Nonpotable Gray Water Sys-
    49. 1506.2 Plumbing Plan Submission. No permit for an
    50. 1506.3 System Changes. No changes or connections shall
    51. 1506.4 Connections to Potable or Reclaimed (Recy-
    52. 1506.5 Initial Cross-Connection Test. A cross-connection test …
    53. 1506.6 On-Site Treated Nonpotable tem Materials. On-site treat…
    54. 1506.7 On-Site Treated Nonpotable Devices and Systems. Devices…
    55. 1506.9 Design and Installation. The design and installation of…
    56. 1506.10 Valves. Valves, except fixture supply control
    57. 1506.11 Signs. Signs in buildings using on-site treated nonpot…
    58. 1506.12 Inspection and Testing. On-site treated nonpotable gra…
  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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