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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Ask AI about this code▸Contents — California Plumbing Code (Title 24, Part 5)
- Chapter 1 — GENERAL CODE PROVISIONS
- Chapter 2 — DEFINITIONS
- Chapter 3 — GENERAL REGULATIONS
- Chapter 4 — PLUMBING FIXTURES AND FIXTURE FITTINGS
- Chapter 5 — WATER HEATERS
- Chapter 6 — WATER SUPPLY AND DISTRIBUTION
- Chapter 7 — SANITARY DRAINAGE
- Chapter 8 — INDIRECT WASTES
- Chapter 9 — VENTS
- Chapter 10 — TRAPS AND INTERCEPTORS
- Chapter 11 — STORM DRAINAGE
- Chapter 12 — FUEL GAS PIPING
- Chapter 13 — HEALTH CARE FACILITIES AND MEDICAL GAS AND MEDICA…
- Chapter 14 — FIRESTOP PROTECTION
▸Chapter 15 — ALTERNATE WATER SOURCES FOR NONPOTABLE APPLICATIONS
Overview- 1501.1 Applicability. [BSC-CG, DWR & HCD 1] The provisions of …
- 1501.2 System Design. [BSC-CG, HCD 1 & DWR]
- 1501.3 Permit. [BSC-CG, HCD 1 & DWR] It shall be
- 1501.4 Component Identification. System components
- 1501.5 Maintenance and Inspection. [BSC-CG, HCD
- 1505.16 .
- 1501.6 Operation and Maintenance Manual. [BSC-
- 1501.7 Minimum Water Quality Requirements. [BSC-
- 1501.8 Material Compatibility. Alternate water source systems …
- 1501.9 Signage. [BSC-CG, HCD 1, HCD 2 & HCD 1-
- 1501.10 System Controls. Controls for pumps, valves, and
- 1502.1 General. Alternate water source systems shall be
- 1502.2 Supply System Inspection and Test. Alternate
- 1502.3 Cross-Connection Inspection and Testing. An
- 1502.4 Separation Requirements. Underground alternate
- 1502.5 Abandonment. Alternate water source systems that
- 1502.6 Sizing. Unless otherwise provided for in this chapter, …
- 1503.1 General. The provisions of this section shall apply to
- 1503.2 System Requirements. Gray water shall be permitted to b…
- 1503.3 Connections to Potable and Reclaimed (Recy-
- 1503.4 Location. No gray water system or part thereof shall
- 1503.5 Plot Plan Submission. No permit for a gray water
- 1503.6 Prohibited Location. Where there is insufficient
- 1503.7 Drawings and Specifications. The Authority Having Juris…
- 1503.8 Procedure for Estimating Gray Water Dis-
- 1503.9 Gray Water System Components. Gray water
- 1504.1 General. Irrigation or disposal fields shall be permitt…
- 1504.2 Required Area of Subsurface Irrigation
- 1504.3 Determination of Maximum Absorption
- 1504.4 Groundwater Level. No excavation for an irrigation fiel…
- 1504.5 Irrigation, Disposal Field and Mulch Basin
- 1504.6 Reserved.
- 1504.7 Reserved .
- 1504.8 Gray Water System Color and Marking Infor-
- 1504.9 Other Collection and Distribution Systems.
- 1504.10 Testing. Building drains and vents for gray water
- 1504.11 Maintenance. Gray water systems and components shall b…
- 1505.1 General. The provisions of Section 1505.0 through
- 1505.2 Permit. It shall be unlawful for a person to construct,
- 1505.3 System Changes. No changes or connections shall
- 1505.4 Connections to Potable or Recycled Water
- 1505.5 Water Pressure. Reclaimed (recycled) water systems supp…
- 1505.6 Initial Cross-Connection Test. A cross-connection
- 1505.7 Recycled Water Supply System Materials.
- 1505.8 Recycled Water Supply System Color and
- 1505.9 Valves. Valves, except fixture supply control valves,
- 1505.13 Signage . Signs in rooms and water closet tanks in
- 1505.14 Inspection and Testing. Recycled water supply
- 1505.10 Hose Bibbs. Hose bibbs shall not be allowed on
- 1505.11 Required Appurtenances. The recycled water
- 1505.12 Pipe Separation in Trenches . Reclaimed (recycled) wat…
- 1505.15 Minimum Water Quality Requirements for
- 1505.16 Maintenance and Inspection. Recycled water
- 1506.1 General. The provisions of this section shall apply
- 1506.2 Plumbing Plan Submission. No permit for an
- 1506.3 System Changes. No changes or connections shall
- 1506.4 Connections to Potable or Recycled Water
- 1506.5 Water Pressure. On-site treated non-potable gray
- 1506.11 Valves. Valves, except fixture supply control
- 1506.12 Signs. Signs in buildings using on-site treated nonpot…
- 1506.13 Inspection and Testing. On-site treated nonpotable gra…
- 1506.6 Initial Cross-Connection Test. A cross-connection test …
- 1506.7 On-Site Treated Nonpotable Gray Water Sys-
- 1506.8 On-Site Treated Nonpotable Gray Water
- 1506.9 On-Site Treated Nonpotable Gray Water Sys-
- 1506.10 Design and Installation. The design and installation o…
- Chapter 16 — NONPOTABLE RAINWATER CATCHMENT SYSTEMS
- Chapter 17 — REFERENCED STANDARDS
- Appendix A — RECOMMENDED RULES FOR SIZING THE WATER SUPPLY SYS…
- Appendix B — EXPLANATORY NOTES ON COMBINATION WASTE AND VENT S…
- Appendix C — ALTERNATE PLUMBING SYSTEMS
- Appendix D — SIZING STORM WATER DRAINAGE SYSTEMS
- Appendix E — MANUFACTURED/MOBILE HOME PARKS AND RECREATIONAL V…
- Appendix F — FIREFIGHTER BREATHING AIR REPLENISHMENT SYSTEMS
- Appendix G — SIZING OF VENTING SYSTEMS
- Appendix H — PRIVATE SEWAGE DISPOSAL SYSTEMS
- Appendix I — INSTALLATION STANDARDS
- Appendix J — COMBINATION OF INDOOR AND OUTDOOR COMBUSTION AND …
- Appendix K — POTABLE RAINWATER CATCHMENT SYSTEMS
- Appendix L — SUSTAINABLE PRACTICES
- Appendix M — PEAK WATER DEMAND CALCULATOR
- Appendix N — IMPACT OF WATER TEMPERATURE ON THE POTENTIAL FOR …
- Appendix O — NON-SEWERED SANITATION SYSTEMS
- Appendix P — PROFESSIONAL QUALIFICATIONS
- Appendix Q — INDOOR HORTICULTURAL FACILITIES
- Appendix R — TINY HOUSES
- Appendix S — ONSITE STORMWATER TREATMENT SYSTEMS