Chapter 16 — NONPOTABLE RAINWATER CATCHMENT SYSTEMS
1603.7 Above Grade. Above grade, storage tanks 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.
of an opaque material, approved for aboveground use in direct sunlight or shall be shielded from direct sunlight. Tanks shall be installed in an accessible location to allow for inspection and cleaning. The tank shall be installed on a foundation or platform that is constructed to accommodate loads in accordance with the California Building Code .
Exception: Tanks may be installed directly on grade in accor- dance with Section 1601.3.
FIGURE 1603.2 1603.8 Below Grade. Rainwater storage tanks installed below grade shall be structurally designed to withstand antic
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NONPOTABLE RAINWATER CATCHMENT SYSTEMS
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TABLE 1603.4
MINIMUM WATER QUALITY
| APPLICATION | MINIMUM TREATMENT | MINIMUM WATER QUALITY |
|---|---|---|
| Car washing | Debris excluder or other approved means in accordance with Section 1603.17, and 100 microns_(100 µm)_in accordance with Section 1603.18 for drip irrigation. |
N/A |
| _Surface,_Subsurface and drip irrigation |
Debris excluder or other approved means in accordance with Section 1603.17, and 100 microns_(100 µm)_ in accordance with Section 1603.18 for drip irrigation. |
N/A |
| Spray irrigation where the maximum storage volume is less than 360 gallons_(1363 L)_ |
Debris excluder or other approved means in accordance with Section 1603.17, and disinfec- tion in accordance with Section 1603.15. |
N/A |
| Spray irrigation where the maximum storage volume is equal to or more than 360 gallons (1363 L) |
Debris excluder or other approved means in accordance with Sec- tion 1603.17. |
Escherichia coli: < 100 CFU/100 mL, and Turbidity: < 10 NTU |
| Urinal and water closet flushing, clothes washing, and trap priming |
Debris excluder or other approved means in accordance with Section 1603.17, and 100 microns_(100 µm)_ in accordance with Section 1603.18. |
Escherichia coli: < 100 CFU/100 mL, and Turbidity: < 10 NTU |
| Ornamental fountains and other water features |
Debris excluder or other approved means in accordance with Section 1603.17. |
Escherichia coli: < 100 CFU/100 mL, and Turbidity: < 10 NTU |
| Cooling tower make-up water |
Debris excluder or other approved means in accordance with Section 1603.17, and 100 microns_(100 µm)_ in accordance with Section 1603.18. |
Escherichia coli: < 100 CFU/100 mL, and Turbidity: < 10 NTU |
For SI units: 1 micron = 1 µm, 1 gallon = 3.785 L
ipated earth or other loads. Holding tank covers shall be capable of supporting an earth load of not less than 300 pounds per square foot (lb/ft [2] ) (1465 kg/m [2] ) where the tank is designed for underground installation. Below grade rainwater tanks installed underground shall be provided with manholes. Below grade storage tanks, located outside of the building, shall be provided with either a manhole not less than 24 inches (610 mm) square or a manhole with an inside diameter of not less than 24 inches (610 mm). Service ports in manhole cov- ers shall be not less than 8 inches (203 mm) in diameter. The manhole opening shall be not less than 20 inches (508 mm) in diameter and located not less than 4 inches (102 mm) above
the surrounding grade. The surrounding grade shall be sloped away from the manhole. Underground tanks shall be ballasted, anchored, or otherwise secured, to prevent the tank from floating out of the ground where empty. The combined weight of the tank and hold down system shall meet or exceed the buoyancy force of the tank.
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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
▸Chapter 16 — NONPOTABLE RAINWATER CATCHMENT SYSTEMS
Overview- 1601.1 Applicability. The provisions of this chapter shall
- 1601.2 System Design. Rainwater catchment systems shall
- 1601.3 Permit. It shall be unlawful for a person to construct,
- 1601.4 Component Identification. System components
- 1601.5 Maintenance and Inspection. Rainwater catchment systems…
- 1601.6 Operation and Maintenance Manual. An operation and main…
- 1601.7 Minimum Water Quality Requirements. The
- 1601.8 Material Compatibility. Rainwater catchment systems sha…
- 1601.9 System Controls. Controls for pumps, valves, and
- 1601.10 Separation Requirements. Underground rainwater catchme…
- 1601.11 Abandonment. Rainwater catchment systems that
- 1601.12 Sizing. Unless otherwise provided for in this chapter,…
- 1602.1 General. The installation, construction, alteration,
- 1602.2 Plumbing Plan Submission. No permit for a
- 1602.3 System Changes. No changes or connections shall
- 1602.4 Connections to Potable or Reclaimed (Recy-
- 1602.5 Initial Cross-Connection Test. Where a portion
- 1602.6 Sizing. The design and size of rainwater drains, gutter…
- 1602.7 Rainwater Catchment System Materials. Rain- 1603.3 Rain…
- 1602.8 Rainwater Catchment System Color and
- 1603.4 Minimum Water Quality. The minimum water
- 1602.9 Deactivation and Drainage for Cross-Connec- shall be in…
- 1603.1 Rainwater Catchment Systems. The design and
- 1603.2 Outside Hose Bibbs. Outside hose bibbs shall be infecti…
- 1603.5 Rainwater Storage Tanks. Rainwater storage tanks
- 1603.6 Location. Rainwater storage tanks shall be permitted to…
- 1603.7 Above Grade. Above grade, storage tanks shall be
- 1603.9 Drainage and Overflow. Rainwater storage tanks
- 1603.10 Opening and Access Protection. Rainwater
- 1603.11 Marking. Rainwater tanks shall be permanently
- 1603.12 Storage Tank Venting. Where venting using
- 1603.13 Pumps. Pumps serving rainwater catchment systems shall…
- 1605.1 General. Rainwater catchment systems shall be
- 1605.2 Supply System Inspection and Test. Rainwater
- 1605.3 Cross-Connection Inspection and Testing. An
- 1603.14 Roof Drains. Primary and secondary roof drains,
- 1603.15 Water Quality Devices and Equipment.
- 1603.16 Freeze Protection. Tanks and piping installed in
- 1603.17 Debris Removal. The rainwater catchment conveyance sys…
- 1603.18 Required Filters. A filter permitting the passage
- 1603.19 Roof Gutters. Gutters shall maintain a minimum
- 1603.20 Rainwater Diversion Valves. Rainwater diversion valves…
- 1604.1 General. Signs in buildings using rainwater shall be
- 1604.2 Commercial, Industrial, Institutional and Res-
- 1604.3 Equipment Room Signs. Each equipment room
- 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