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Earlier editions: 20222019

Chapter 15 — ALTERNATE WATER SOURCES FOR NONPOTABLE APPLICATIONS

1503.6 Prohibited Location. Where there is insufficient

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.

lot area or inappropriate soil conditions for adequate absorption, no gray water system shall be permitted.

ALTERNATE WATER SOURCES FOR NONPOTABLE APPLICATIONS

TABLE 1503.4 LOCATION OF GRAY WATER SYSTEM [7]

MINIMUM HORIZONTAL DISTANCE IN
CLEAR REQUIRED FROM
SURGE TANK
(feet)
SUBSURFACE AND
SUBSOIL IRRIGATION FIELD
AND MULCH BED
(feet)
DISPOSAL FIELD
Building structures1 52, 9 23, 8 5
Property line adjoining private property 5 58 5
Water supply wells4 50 100 100
Streams and lakes4 50 1005, 10 1005
Sewage pits or cesspools 5 5 5
Sewage disposal field10 5 46 46
Septic tank 0 5 5
On-site domestic water service line 5 0 0
Pressurized public water main 10 107 107

For SI units: 1 foot = 304.8 mm

Notes: 1 Building structures do not include porches and steps, whether covered or uncovered, breezeways, roofed carports, roofed porte cocheres, roofed patios, carports, covered walks, covered driveways, and similar structures or appurtenances. 2 The distance shall be permitted to be reduced to 0 feet for aboveground tanks where first approved by the Authority Having Jurisdiction. 3 Underground tanks shall not be located within a 45 degree angle from the bottom of the foundation, or they shall be designed to address the surcharge imposed by the structure. The distance may be reduced to six (6) inches (153 mm) for aboveground tanks when first approved by the Enforcing Agency. 4 Where special hazards are involved, the distance required shall be increased as directed by the Authority Having Jurisdiction. 5 These minimum clear horizontal distances shall apply between the irrigation or disposal field and the ocean mean higher high tide line. 6 Add 2 feet (610 mm) for each additional foot of depth more than 1 foot (305 mm) below the bottom of the drain line. 7 For parallel construction or crossings, approval by the Authority Having Jurisdiction shall be required. 8 The distance shall be permitted to be reduced to 1 1 ⁄ 2 feet (457 mm) for drip and mulch basin irrigation systems. 9 The distance shall be permitted to be reduced to 0 feet for surge tanks of 75 gallons (284 L) or less. 10 The minimum horizontal distance may be reduced to 50 feet (15 240 mm) for irrigation or disposal fields utilizing gray water which has been filtered prior to entering the distribution piping.

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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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