Chapter 6 — WATER SUPPLY AND DISTRIBUTION
601.2 Water Supply and Flushing.
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.
Each plumbing fixture shall be provided with an adequate supply of potable running water piped thereto in an approved manner, so arranged as to flush and keep it in a clean and sanitary condition without danger of backflow or cross-connection. Water closets and urinals shall be flushed using an approved flush tank or flushometer valve.
Exceptions:
(1) Listed fixtures that do not require water for their operation and are not connected to the water supply.
(2) Where not deemed necessary for safety and sanitation by the Authority Having Jurisdiction. (3) [HCD 1 & HCD 2] For limited-density owner-built rural dwellings, potable water shall be available to the dwelling site, although such water need not be pressur- ized. Where water is not piped from a well, spring, cistern or other source, there shall be a minimum reserve of 50 gallons (189 L) of potable water available. Where water delivery is pressurized, piping shall be installed in accor- dance with the provisions of this chapter. (4) [HCD 1, HCD 2 & DWR] For all residential occupan- cies, alternate water sources may be allowed as speci- fied in Chapter 15 of this code in addition to potable
water.
(5) [BSC-CG & DWR] For non-residential occupancies, alternate water sources may be allowed as specified in Chapter 15 of this code.
(6) [DWR] Where a public agency requires a building to use recycled water to flush water closets and urinals in accordance with California Water Code 13554. 601.2.1 Submeters. [HCD 1] Submeters (or meters) shall be installed to measure potable and reclaimed (recycled) water (hot and cold) that is supplied for the exclusive use of an individual dwelling unit within a newly constructed, multiunit rental residential structure; or for the use of an individual dwelling unit within a newly constructed mixed-use rental residential/commer- cial structure. Submeters (or meters) shall be installed in accordance with this code and the manufacturer’s installation instructions.
See Water Code Section 517 for definitions of “multiunit residential structure” and “mixed-use resi-
dential and commercial structure.” See also Civil Code commencing with Section 1954.201.
Exemptions:
(1) Long-term health care facilities as defined in Health and Safety Code Section 1418.
(2) Low-income housing as defined in Health and Safety Code Section 17922.14 (c)(2)(B).
(3) Residential care facilities for the elderly as defined in Health and Safety Code Section 1569.2 (p)(1).
(4) Housing at a place of education as defined in Title 24 of the California Code of Regulations, Califor- nia Building Code, Part 2, Section 202.
(5) Time-share property as defined in Business and Pro- fessions Code Section 11212, Subdivision (aa).
601.2.1.1 Approved Submeters. [HCD 1] Sub- meters (or meters) shall be approved in accordance with the Business and Professions Code, Division 5.
601.2.1.2 Submeter Testing. [HCD 1] Submeter (or meter) testing shall be in accordance with the California Code of Regulations, Title 4, Division 9, Chapter 3, Article 1; Civil Code, Division 3, Part 4, Title 5; and Business and Professions Code, Divi- sion 5.
601.2.2 Hot and Cold Water Required. In occupancies where plumbing fixtures are installed for private use, hot water shall be required for bathing, washing, laundry, cooking purposes, dishwashing or maintenance. In occupancies where plumbing fixtures are installed for public use, hot water shall be required for bathing and washing purposes. This requirement shall not supersede the requirements for individual temperature control limitations for public lavatories and public and private bidets, bathtubs, whirlpool bathtubs, and shower control valves.
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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
Overview- 601.1 Applicability. This chapter shall govern the materials,
- 601.2 Water Supply and Flushing. Each plumbing fixture shall b…
- 601.3 Identification of a Potable and Nonpotable
- 601.4 Schools of Cosmetology and Cosmetological
- 601.5 Meat and Poultry Processing Plants. [AGR]
- 601.6 Collection Centers and Facilities. [AGR]
- 601.7 Renderers. [AGR] This area shall be provided with
- 601.8 Horse Meat and Pet Food Establishments. [AGR]
- 602.1 Prohibited Installation. No installation of potable
- 602.2 Cross-Contamination. No person shall make a connection o…
- 602.3 Backflow Prevention. No plumbing fixture, device,
- 602.4 Approval by Authority. No water piping supplied
- 603.1 General. Cross-connection control shall be provided
- 603.2 Approval of Devices or Assemblies. Before a
- 603.3 Backflow Prevention Devices, Assemblies, and
- 603.4 General Requirements. Assemblies shall comply
- 603.5 Specific Requirements. Specific requirements for
- 604.1 Pipe, Tube, and Fittings. Pipe, tube, fittings, solvent …
- 604.2 Lead Content. The maximum allowable lead content
- 604.3 Copper or Copper Alloy Tube. Copper or copper
- 604.4 Hard-Drawn Copper or Copper Alloy Tubing.
- 604.5 Flexible Connectors. Flexible water connectors
- 604.6 Cast-Iron Fittings. Cast-iron fittings up to and
- 604.7 Malleable Iron Fittings. Malleable iron water fittings s…
- 604.8 Previously Used Piping and Tubing. Piping and
- 604.9 Epoxy Coating. The epoxy coating used on existing, under…
- 604.10 Plastic Materials. Approved plastic materials shall
- 604.11 Solder. Solder shall comply with the requirements of
- 604.12 Flexible Corrugated Connectors. Flexible corrugated con…
- 604.13 Water Heater Connectors. Flexible metallic (copper and …
- 605.1 Copper or Copper Alloy Pipe, Tubing, and
- 605.2 CPVC Plastic Pipe and Joints. CPVC plastic pipe
- 605.3 CPVC/AL/CPVC Plastic Pipe and Joints. Chlorinated polyvi…
- 605.4 Ductile Iron Pipe and Joints. Ductile iron pipe
- 605.5 Galvanized Steel Pipe and Joints. Galvanized
- 605.6 PE Plastic Pipe/Tubing and Joints. PE plastic
- 605.7 PE-AL-PE Plastic Pipe/Tubing and Joints. PEAL-PE plastic…
- 605.8 PE-RT. Polyethylene of raised temperature (PE-RT)
- 605.9 PEX Plastic Tubing and Joints. PEX plastic tubing and fi…
- 605.10 PEX-AL-PEX Plastic Tubing and Joints. PEXAL-PEX plastic…
- 605.11 Polypropylene (PP) Piping and Joints. PP pipe
- 605.12 PVC Plastic Pipe and Joints. PVC plastic pipe
- 605.13 Stainless Steel Pipe and Joints. Joining methods for st…
- 605.14 Slip Joints. In water piping, slip joints shall be perm…
- 605.15 Dielectric Unions. Dielectric unions where installed
- 605.16 Joints Between Various Materials. Joints
- 606.1 General. Valves up to and including 2 inches (50
- 606.2 Fullway Valve. A fullway valve controlling outlets
- 606.3 Multidwelling Units. In multidwelling units, one or
- 606.4 Multiple Openings. Valves used to control two or
- 606.5 Control Valve. A control valve shall be installed
- 606.6 Accessible. Required shutoff or control valves shall
- 606.7 Multiple Fixtures. A single control valve shall be
- 606.8 [OSHPD 1, 1R, 2, 3, 4 & 5] Each riser or branch
- 606.9 Check Valve Required. All systems that circulate
- 606.10 Leak Detection Devices. Where leak detection
- 607.1 General. Potable water supply tanks shall be installed in
- 607.2 Private Well Water Tanks. Pressurized potable water
- 607.3 Potable Water Tanks. Potable water supply tanks,
- 607.4 Venting. Tanks used for potable water shall be tightly
- 607.5 Overflow. Tanks shall have not less than a 16 square
- 607.6 Valves. Pressurized tanks shall be provided with a listed
- 608.1 Inadequate Water Pressure. Where the water pressure in t…
- 608.2 Excessive Water Pressure. Where static water
- 608.3 Expansion Tanks, and Combination Tempera-
- 608.4 Pressure Relief Valves. Each pressure relief valve
- 608.5 Discharge Piping. The discharge piping serving a
- 608.6 Water-Heating Devices. A water-heating device
- 608.7 Vacuum Relief Valves. Where a hot-water storage
- 609.1 Installation. Water piping shall be adequately supported…
- 609.2 Trenches. Water pipes shall not be run or laid in the
- 609.3 Under Concrete Slab. Water piping installed within
- 609.4 Testing. Upon completion of a section or of the entire
- 609.5 Unions. Unions shall be installed in the water supply
- 609.6 Location. Except as provided in Section 609.7, no
- 609.7 Abutting Lot. Nothing contained in this code shall
- 609.8 Pumps. Pumps shall be installed in accordance with
- 609.9 Low-Pressure Cutoff Required on Booster
- 609.10 Disinfection of Potable Water System. New or
- 609.11 Water Hammer. [Not adopted by HCD] Building
- 609.12 Pipe Insulation. Insulation of domestic hot water
- 610.1 Size. The size of each water meter and each potable
- 610.2 Pressure Loss. Where a water filter, water softener,
- 610.3 Quantity of Water. The quantity of water required to be
- 610.4 Sizing Water Supply and Distribution Systems.
- 610.5 Sizing per Appendices A, C, and M . Except as
- 610.6 Friction and Pressure Loss. Except where the type
- 610.7 Conditions for Using Table 610.4. On a proposed
- 610.8 Size of Meter and Building Supply Pipe Using
- 610.9 Size of Branches. Where Table 610.4 is used, the minimum…
- 610.10 Sizing for Flushometer Valves. Where using
- 610.11 Sizing Systems for Flushometer Tanks. The size
- 610.12 Sizing for Velocity. Water piping systems shall not
- 610.13 Exceptions. The provisions of this section relative
- 611.1 Application. Drinking water treatment units shall
- 611.2 Air Gap Discharge. Discharge from drinking water
- 611.3 Connection Tubing. The tubing to and from drinking water…
- 611.4 Sizing of Residential Softeners. Residential-use
- 612.1 Installation. Residential Sprinkler Systems shall be
- 613.1 The domestic water-heating equipment and distribu-
- 613.2 At least two pieces of hot-water-heating equipment shall
- 613.3 Instantaneous heaters are permitted for supplying hot
- 613.4 Water storage tanks shall be fabricated of corrosion-
- 613.5 Temperature control valves shall be provided to auto-
- 613.6 Hot-water distribution system serving patient care areas
- 613.7 At fixtures where water exceeding 125°F (52°C) is acces-
- 613.8 Sectionalizing valves shall be provided as required by
- 613.9 Hot water distribution shall include test ports and valved
- 614.1 Dialysis water feedlines shall be CPVC (chlorinated
- 614.2 All piping for multistation or central dialysis units sh…
- 614.3 All valves shall be located in accessible locations.
- 614.4 Piping and valves shall be identified according to their
- 614.5 A means of preventing backwashing or flushing of the
- 614.6 A continuous audible alarm shall sound at the nurses’
- 614.7 Water treatment equipment and water used for dialysis
- 614.8 A diagram of all piping as installed shall be posted at …
- 615.1 Uses Not Permitted.
- 615.2 [OSHPD 1, 1R, 2, 3, 4 & 5] Non-potable water sys-
- 615.3 [OSHPD 1, 1R, 2, 3, 4 & 5] Outlets for non-potable
- 616.1 For new acute care hospital buildings submitted after
- 616.2 The emergency supply of water shall be provided at ade-
- 616.3 Storage tank connections and circulation shall be
- 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
- 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