Graywater/recycled‑water piping requirements and rainwater capture provisions

Grounded in the retrieved California Green Building Standards Code (CALGreen) — click a citation to read the verbatim passage:

• CALGreen § 303.5 High relevance — show source text

  Where approved, nonwater urinals with drain cleansing action (formerly hybrid urinals), as defined in Chapter 2, shall be considered nonwater urinals.

  A4.303.5 Hot water recirculation systems. One- and two-family dwellings shall be equipped with a demand hot water recirculation system, as defined in Chapter 2. The demand hot water recirculation system shall be installed in accordance with the California Plumbing Code, California Energy Code and the manufacturer’s installation instructions.

  SECTION A4.304—OUTDOOR WATER USE

  A4.304.1 Rainwater catchment systems. An approved rainwater catchment system is designed and installed to use rainwater generated by at least 65 percent of the available roof area. Rainwater catchment systems shall be designed and installed in accordance with the California Plumbing Code.

  A4.304.2 Potable water elimination. When landscaping is provided and as allowed by local ordinance, a water efficient landscape irrigation design that eliminates the use of potable water beyond the initial requirements for plant installation and establishment shall be provided. Methods used to accomplish the requirements of this section shall comply with the requirements of the California Building Standards Code and shall include, but not be limited to, the following:

  1. Use of captured rainwater.
  2. Use of recycled water.
  3. Water treated for irrigation purposes and conveyed by a water district or public entity.
  4. Use of graywater.
  5. Use of drought tolerant plants.

  A4.304.3 Landscape water meters. For new water service connections, landscaped irrigated areas less than 5,000 square feet shall be provided with separate submeters or metering devices for outdoor potable water use.

  SECTION A4.305 —WATER REUSE SYSTEMS

  A4.305.1 Graywater. Alternative plumbing piping is installed to permit the discharge from the clothes washer or other fixtures to be used for an irrigation system in compliance with the California Plumbing Code.

  A4.305.2 Recycled water piping. Based on projected availability, dual water piping is installed for future use of recycled water at the following locations:

  1. Interior piping for the use of recycled water is installed to serve all water closets, urinals and floor drains.
  2. Exterior piping is installed to transport recycled water from the point of connection to the structure. Recycled water systems shall be designed and installed in accordance with the California Plumbing Code.

  A4.305.3 Recycled water for landscape irrigation. Recycled water is used for landscape irrigation.

  2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A4-13

  on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

  APPENDIX A4 — RESIDENTIAL VOLUNTARY MEASURES

  SECTION A4.306 —INNOVATIVE CONCEPTS AND LOCAL ENVIRONMENTAL CONDITIONS

  A4.306.1 Innovative concepts and local environmental conditions. The provisions of this code are not intended to prevent the use of any alternate material, appliance, installation, device, arrangement, method, design or method of construction not specifically prescribed by this code. This code does not limit the authority of city, county, or city and county government to make necessary changes to the provisions contained in this code pursuant to Section 101.7.1.

  APPENDIX A4-14 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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• CALGreen § 504.4.8 High relevance — show source text

  A5.504.4.8

  Product GWP Limits Table 5.409.3

  Referenced Organizations and Standards Chapter 6 Renewable Energy A5.211

  Site Development 4.106, 5.106, A4,106, A5.106 Bicycle parking and changing rooms 5.106.4, A5.106.4.3, Table A5.106.4.3 Bird friendly building design A5.107 Building orientation Appendix A6.1 (OSHPD), A5.106.9 Designated parking for clean air vehicles A5.106.5.1 Exterior wall shading A5.106.7 Grading and paving 4.106.3, 5.106.10 Heat island effect – cool roof Tables A4.106.5(1) – (4), A5.106.11.2, Table

  A5.106.11.2 Heat island effect – hardscape alternatives A5.106.11, A5.106.11.1 Landscape design A4.106.3 Light pollution reduction 5.106.8 Low impact development A5.106.3 Reduce parking capacity A5.106.6 Shade trees 5.106.12, A5.106.11.3 Soil analysis and protection A4.106.2 Storm water management A5.106.2 Water permeable surfaces A4.106.4 Site Preservation A4.104, A5.104 Reduce development footprint and optimize open space A5.104.1 Site Selection A4.103, A5.103 Brownfield, greyfield or infill site development A5.103.2 Community connectivity A4.103.2, A5.103.1

  Voluntary Measures 301.1, 306 Voluntary Tiers 304, 305, 306, A4.601, A5.601

  Water Resistance and Moisture Management 5.407, 5.505, A4.407, Appendix A6.1 (OSHPD) A5.407 Moisture control 4.505, 5.407.2, 5.505, Appendix A6.1 (OSHPD) A5.407.9, Appendix A6.1 (OSHPD) A5.505.2 Weather protection 5.407.1, A5.407.3

  Water Reuse Systems A4.305 Graywater A4.305.1, A5.304.8 Recycled water for landscape irrigation A4.305.3 Recycled water piping A4.305.2 Water Use, Indoor 4.303, 5.303, A4.303, A5.203

  Appliances A4.303.3, A5.303.3, Appendix A6.1 (OSHPD) A5.210 Dual plumbing A5.303.5 Fixture flow rates 4.303.1, Table A5.303.2.3.1, 5.303.2.3.1, A4.303 Kitchen faucets and dishwashers

  A4.303.1

  Meters 4.303.2, 5.303.1 Multiple showerheads serving one shower 4.303.1.3.2, 5.303.3.3.2 Nonwater urinals and waterless toilets

• CALGreen § 303.1 High relevance — show source text

  2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A4-11

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  APPENDIX A4-12 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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  A4 RESIDENTIAL VOLUNTARY MEASURES

  DIVISION A4.3 – WATER EFFICIENCY AND CONSERVATION

  SECTION A4.301—GENERAL (RESERVED)

  SECTION A4.302—DEFINITIONS (RESERVED)

  SECTION A4.303—INDOOR WATER USE

  A4.303.1 Kitchen faucets. The maximum flow rate of kitchen faucets shall not exceed 1.5 gallons per minute at 60 psi. Kitchen faucets may temporarily increase the flow above the maximum rate, but not to exceed 2.2 gallons per minute at 60 psi, and must default to a maximum flow rate of 1.5 gallons per minute at 60 psi.

  Note: Where complying faucets are unavailable, aerators or other means may be used to achieve reduction.

  A4.303.2 Alternate water sources for nonpotable applications. Alternate nonpotable water sources are used for indoor potable water reduction. Alternate nonpotable water sources shall be installed in accordance with the California Plumbing Code.

  A4.303.3 Appliances. Install at least one qualified ENERGY STAR dishwasher or clothes washer.

  Note: See Section A5.303.3 for nonresidential dishwashers and clothes washers.

  A4.303.4 Nonwater urinals and waterless toilets. Nonwater urinals or composting toilets are installed.

  Where approved, nonwater urinals with drain cleansing action (formerly hybrid urinals), as defined in Chapter 2, shall be considered nonwater urinals.

  A4.303.5 Hot water recirculation systems. One- and two-family dwellings shall be equipped with a demand hot water recirculation system, as defined in Chapter 2. The demand hot water recirculation system shall be installed in accordance with the California Plumbing Code, California Energy Code and the manufacturer’s installation instructions.

  SECTION A4.304—OUTDOOR WATER USE

  A4.304.1 Rainwater catchment systems. An approved rainwater catchment system is designed and installed to use rainwater generated by at least 65 percent of the available roof area. Rainwater catchment systems shall be designed and installed in accordance with the California Plumbing Code.

  A4.304.2 Potable water elimination. When landscaping is provided and as allowed by local ordinance, a water efficient landscape irrigation design that eliminates the use of potable water beyond the initial requirements for plant installation and establishment shall be provided. Methods used to accomplish the requirements of this section shall comply with the requirements of the California Building Standards Code and shall include, but not be limited to, the following:

  1. Use of captured rainwater.
  2. Use of recycled water.
  3. Water treated for irrigation purposes and conveyed by a water district or public entity.
  4. Use of graywater.
  5. Use of drought tolerant plants.

  A4.304.3 Landscape water meters. For new water service connections, landscaped irrigated areas less than 5,000 square feet shall be provided with separate submeters or metering devices for outdoor potable water use.

• CALGreen § 305.2 High relevance — show source text

  A4.305.2 Recycled water piping. Based on projected availability, dual water piping is installed for future use of recycled water at the following locations:

  1. Interior piping for the use of recycled water is installed to serve all water closets, urinals and floor drains.
  2. Exterior piping is installed to transport recycled water from the point of connection to the structure. Recycled water systems shall be designed and installed in accordance with the California Plumbing Code.

  A4.305.3 Recycled water for landscape irrigation. Recycled water is used for landscape irrigation.

  2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A4-13

  on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

  APPENDIX A4 — RESIDENTIAL VOLUNTARY MEASURES

  SECTION A4.306 —INNOVATIVE CONCEPTS AND LOCAL ENVIRONMENTAL CONDITIONS

  A4.306.1 Innovative concepts and local environmental conditions. The provisions of this code are not intended to prevent the use of any alternate material, appliance, installation, device, arrangement, method, design or method of construction not specifically prescribed by this code. This code does not limit the authority of city, county, or city and county government to make necessary changes to the provisions contained in this code pursuant to Section 101.7.1.

  APPENDIX A4-14 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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  A4 RESIDENTIAL VOLUNTARY MEASURES

  DIVISION A4.4 – MATERIAL CONSERVATION AND RESOURCE EFFICIENCY

  SECTION A4.401—GENERAL (RESERVED)

  SECTION A4.402—DEFINITIONS

  A4.402.1 Definitions. The following terms are defined in Chapter 2.

  ASSEMBLY (ASSEMBLY PRODUCT).

  POSTCONSUMER CONTENT.

  PRECONSUMER (OR POSTINDUSTRIAL) CONTENT.

  PROPORTIONAL RECYCLED CONTENT (PRC M ).

  RECYCLED CONTENT (RC).

  RECYCLED CONTENT VALUE (RCV).

  Assembly products (RCV A ). Materials (RCV M ).

  SECTION A4.403—FOUNDATION SYSTEMS

  A4.403.1 Frost protected foundation systems. As allowed by local conditions, utilize a Frost-Protected Shallow Foundation (FPSF) in compliance with the California Residential Code (CRC). When an FPSF foundation system is installed, the manual required by Section 4.410.1 shall include instructions to the owner or occupant regarding the necessity for heating the structure as required in Section R403.3 of the California Residential Code.

  A4.403.2 Reduction in cement use. As allowed by the enforcing agency, cement used in foundation mix design shall be reduced as follows:

  Tier 1. Not less than a 20 percent reduction in cement use.

  Tier 2. Not less than a 25 percent reduction in cement use.

  Note: Products commonly used to replace cement in concrete mix designs include, but are not limited to:

  1. Fly ash.

  2. Slag.

  3. Silica fume.

  4. Rice hull ash.

  SECTION A4.404—EFFICIENT FRAMING TECHNIQUES

• CALGreen § 303.3 High relevance — show source text

  303.3** Install at least one qualified ENERGY STAR dishwasher or
  clothes washer.||
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  | |A4.303.4Nonwater urinals or waterless toilets are installed.||||||| |A4.303.5One- and two-family dwellings shall be equipped with a
  demand hot water recirculation system.||||||| |Outdoor Water Use||||||| |4.304.1 Residential developments shall comply with a local water
  efficient landscape ordinance or the current California Department of
  Water Resources’ Model Water Efficient Landscape Ordinance
  (MWELO), whichever is more stringent.||||||| |A4.304.1A rainwater capture, storage and re-use system is designed
  and installed.||||||| |A4.304.2A landscape design is installed, which does not utilize
  potable water.||||||| |A4.304.3 For new water service connections, landscaped irrigated
  areas less than 5,000 square feet shall be provided with separate
  submeters or metering devices for outdoor potable water use.||||||| |Water Reuse Systems||||||| |A4.305.1Piping is installed to permit future use of a graywater
  irrigation system served by the clothes washer or other fixtures.||
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  | |A4.305.2 Recycled water piping is installed.||
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  | |A4.305.3Recycled water is used for landscape irrigation.||||||| |Innovative Concepts and Local Environmental Conditions||||||| |A4.306.1Items in this section are necessary to address innovative
  concepts or local environmental conditions.||||||| |Item 1|
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  APPENDIX A4-26 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

• CALGreen § 305.1 High relevance — show source text

  305.1**Piping is installed to permit future use of a graywater
  irrigation system served by the clothes washer or other fixtures.||
  |
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  | |A4.305.2 Recycled water piping is installed.||
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  | |A4.305.3Recycled water is used for landscape irrigation.||||||| |Innovative Concepts and Local Environmental Conditions||||||| |A4.306.1Items in this section are necessary to address innovative
  concepts or local environmental conditions.||||||| |Item 1|
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  APPENDIX A4-26 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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  APPENDIX A4 — RESIDENTIAL VOLUNTARY MEASURES

  SECTION A4.602—RESIDENTIAL OCCUPANCIES APPLICATION CHECKLIST—continued

  FEATURE OR MEASURE	LEVELS APPLICANT TO SELECT ELECTIVE MEASURES	Col3	Col4	VERIFICATIONS ENFORCING AGENCY TO SPECIFY VERIFICATION METHOD	Col6	Col7
  FEATURE OR MEASURE	Mandatory	Prerequisites and electives1	Prerequisites and electives1	Enforcing Agency  All	Installer or Designer  All	Third party  All
  FEATURE OR MEASURE	Mandatory	Tier 1	Tier 2	Tier 2	Tier 2	Tier 2
  MATERIAL CONSERVATION AND RESOURCE EFFICIENCY
  Foundation Systems
  A4.403.1A Frost-protected Shallow Foundation (FPSF) is designed and constructed.						
  A4.403.2Cement use in foundation mix design is reduced. Tier 1. Not less than a 20 percent reduction in cement use. **Tier 2.

• CALGreen § 301.1 High relevance — show source text

  Voluntary Measures 301.1, 306 Voluntary Tiers 304, 305, 306, A4.601, A5.601

  Water Resistance and Moisture Management 5.407, 5.505, A4.407, Appendix A6.1 (OSHPD) A5.407 Moisture control 4.505, 5.407.2, 5.505, Appendix A6.1 (OSHPD) A5.407.9, Appendix A6.1 (OSHPD) A5.505.2 Weather protection 5.407.1, A5.407.3

  Water Reuse Systems A4.305 Graywater A4.305.1, A5.304.8 Recycled water for landscape irrigation A4.305.3 Recycled water piping A4.305.2 Water Use, Indoor 4.303, 5.303, A4.303, A5.203

  Appliances A4.303.3, A5.303.3, Appendix A6.1 (OSHPD) A5.210 Dual plumbing A5.303.5 Fixture flow rates 4.303.1, Table A5.303.2.3.1, 5.303.2.3.1, A4.303 Kitchen faucets and dishwashers

  A4.303.1

  Meters 4.303.2, 5.303.1 Multiple showerheads serving one shower 4.303.1.3.2, 5.303.3.3.2 Nonwater urinals and waterless toilets

  A4.303.4, A5.303.4.1 Plumbing fixtures and fittings 4.303.1, 4.303.2, 5.303.3, 5.303.6 Tier 1, 12% savings; Tier 2, 20% savings; and 25% savings A5.303.2.1, A5.303.2.3.1, A5.303.2.3.2,

  A5.303.2.3.3

  Wastewater reduction 5.303.4

  Water Use Baseline Table A5.303.2.2

  Water Use, Outdoor 4.304, 5.304, A4.304, A5.304

  Graywater irrigation system A5.304.8 Low-water consumption irrigation system A4.304.1 Outdoor potable water meters A4.304.3, A5.304.2 Potable water elimination A4.304.2 Previously developed sites A5.304.7 Rainwater or stormwater collection systems A4.304.1 Restoration of areas disturbed by construction A5.304.6 Worksheet Baseline Water Use Chapter 8, (WS-1) 12%, 20% or 25% Reduction Water Use Calculation Table Chapter 8, (WS-2) Building Reuse Chapter 8, (WS-3) Whole Building Life Cycle Assessment 5.409.2, Chapter 8, (WS-4) Product GWP Compliance— Prescriptive Path 5.409.3, Chapter 8, (WS-5) Building Reuse Tier 1 and Tier 2 Chapter 8, (WS-6) Whole Building Life Cycle Assessment A5.409.2, Chapter 8, (WS-7) Product GWP Compliance— Prescriptive Path A5.409.3,

• CALGreen § 1601.10 Medium relevance — show source text

  1601.10 Separation Requirements. Underground rainwater catchment service piping shall be separated from the building sewer in accordance with Section 609.2. Treated nonpotable water pipes shall be permitted to be run or laid in the same trench as potable water pipes with a 12 inch (305 mm) minimum vertical and horizontal separation where both pipe materials are approved for use within a building. Where horizontal piping materials do not meet this requirement, the minimum separation shall be increased to 60 inches (1524 mm). The potable water piping shall be installed at an elevation above the treated nonpotable water piping. 1601.11 Abandonment. Rainwater catchment systems that are no longer in use, or fail to be maintained in accordance with Section 1601.5, shall be abandoned. Abandonment shall comply with Section 1601.11.1 and Section 1601.11.2.

  1601.11.1 General. An abandoned system or part thereof covered under the scope of this chapter shall be disconnected from remaining systems, drained, plugged, and capped in an approved manner. 1601.11.2 Underground Tank. An underground water storage tank that has been abandoned or otherwise discontinued from use in a system covered under the scope of this chapter shall be completely drained and filled with earth, sand, gravel, concrete, or other approved material or removed in a manner satisfactory to the Authority Having Jurisdiction. 1601.12 Sizing. Unless otherwise provided for in this chapter, rainwater catchment piping shall be sized in accordance with Chapter 6 for sizing potable water piping.

  1602.0 Nonpotable Rainwater Catchment Systems. 1602.1 General. The installation, construction, alteration, and repair of rainwater catchments systems intended to supply uses such as water closets, urinals, trap primers for floor drains and floor sinks, irrigation, industrial processes, water features, cooling tower makeup and other uses shall be approved by the Authority Having Jurisdiction. Rainwater catchment systems for collecting precipitation from rooftops shall comply with ARCSA/ASPE/ANSI 63. 1602.2 Plumbing Plan Submission. No permit for a rainwater catchment system shall be issued until complete plumbing plans, with data satisfactory to the Authority Having Jurisdiction, have been submitted and approved. 1602.3 System Changes. No changes or connections shall be made to either the rainwater catchment system or the potable water system within a site containing a rainwater catchment system requiring a permit without approval by the Authority Having Jurisdiction. 1602.4 Connections to Potable or Reclaimed (Recy- cled) Water Systems. Rainwater catchment systems shall have no direct connection to a potable water supply or alternate water source system. Exceptions: (1) Potable water, on-site treated nonpotable gray water, or reclaimed (recycled) water is permitted to be used as makeup water for a rainwater catchment system provided the connection is protected by an air gap in accordance with this code.

  (2) A potable water supply may be connected temporarily for the initial cross-connection test of the rainwater catchment system as required in Section 1605.3.2. 1602.5 Initial Cross-Connection Test. Where a portion of a rainwater catchment system is installed within a building, a cross-connection test is required in accordance with Section 1605.3.

• CALGreen § 220.0 Medium relevance — show source text

  220.0 – R –

  Rainwater. [BSC-CG & HCD 1] Precipitation on any pub- lic or private parcel that has not entered an offsite storm drain system or channel, a flood control channel, or any other stream channel, and has not previously been put to beneficial use. Rainwater Catchment System. [BSC-CG & HCD 1] A facility designed to capture, retain, and store rainwater flow- ing off a building, parking lot, or any other manmade imper- vious surface for subsequent onsite use. Rainwater catchment system is also known as “Rainwater Harvesting System” or “Rainwater Capture System.” Rainwater Storage Tank. The central component of the rainwater catchment system. Also, known as a cistern or rain barrel.

  2025 CALIFORNIA PLUMBING CODE 41

  ), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.

  DEFINITIONS

  Receiving Landscape. [BSC-CG & HCD 1] Includes features such as soil, basins, swales, mulch, and plants.

  Receptor. An approved plumbing fixture or device of such material, shape, and capacity as to adequately receive the discharge from indirect waste pipes, so constructed and located as to be readily cleaned.

  Reclaimed (Recycled) Water. [BSC-CG, HCD 1 & DWR] Nonpotable water that meets California State Water Resources Control Board statewide uniform criteria for dis- infected tertiary recycled water. Reclaimed (recycled) water is also known as “recycled water” or “reclaimed water”.

  Recycled Water Supply System. [DWR] The building supply pipe, the water distribution pipes, and the necessary connecting pipes, fittings, control valves, backflow preven- tion devices, and all appurtenances carrying or supplying reclaimed (recycled) water in or adjacent to the building or within the premises.

  Registered Design Professional. An individual who is registered or licensed by the laws of the state to perform such design work in the jurisdiction.

  Regulating Equipment. Includes valves and controls used in a plumbing system that is required to be accessible or readily accessible.

  Relief Vent. A vent, the primary function of which is to provide circulation of air between drainage and vent systems or to act as an auxiliary vent on a specially designed system.

  Remote Outlet. Where used for sizing water piping, it is the furthest outlet dimension, measuring from the meter, either the developed length of the cold-water piping or through the water heater to the furthest outlet on the hot-water piping.

  Rim. See Flood-Level Rim.

  Riser. A water supply pipe that extends vertically one full story or more to convey water to branches or fixtures.

  Roof Drain. A drain installed to receive water collecting on the surface of a roof and to discharge it into a leader, downspout, or conductor.

  Roof Washer. A device or method for removal of sediment

  and debris from a collection surface by diverting initial rainfall from entry into the cistern(s). Also, known as a first flush device.

• CALGreen § 4-11 Medium relevance — show source text

  (Equation A4.4-11) Weight of material (percent) = [Weight of material (lbs) ÷ Weight of assembly (lbs)] × 100 (See Equation A4.4-7) RC M (percent) = Postconsumer content percentage + ( [1] / 2 ) Preconsumer content percentage

  Method 2: Recycled content (postconsumer and preconsumer) provided in pounds

  (Equation A4.4-12) PRC M (percent) = [RC M (lbs) ÷ Weight of material (lbs)] × 100 (Equation A4.4-13) RC M (lbs) = Postconsumer content (lbs) + ( [1] / 2 ) Preconsumer content (lbs)

  Note: If the manufacturer reports total recycled content of a material as one percentage in lieu of separately reporting preconsumer and postconsumer values, the total shall be considered preconsumer recycled material.

  A4.405.3.1.5 Alternate method for concrete. When Supplementary Cementitious Materials (SCMs), such as fly ash or ground blast furnace slag cement, are used in concrete, an alternate method of calculating and reporting recycled content in concrete products shall be permitted. When determining the recycled content value, the percent recycled content shall be multiplied by the cost of the cementitious materials only, not the total cost of the concrete.

  A4.405.4 Use of building materials from rapidly renewable sources. One or more of the following materials manufactured from rapidly renewable sources or agricultural by-products is used:

  1. Insulation.

  2. Bamboo or cork.

  3. Engineered products.

  4. Agricultural based products.

  5. Other products acceptable to the enforcing agency.

  Note: The intent of this section is to utilize building materials and products which are typically harvested within a 10-year or shorter cycle.

  SECTION A4.406—ENHANCED DURABILITY AND REDUCED MAINTENANCE (RESERVED)

  SECTION A4.407—WATER RESISTANCE AND MOISTURE MANAGEMENT

  A4.407.1 Drainage around foundations. Install foundation and landscape drains which discharge to a dry well, sump, bioswale or other approved on-site location.

  A4.407.2 Roof drainage. Install gutter and downspout systems to route water at least 5 feet away from the foundation or connect to landscape drains which discharge to a dry well, sump, bioswale, rainwater capture system or other approved on-site location.

  A4.407.3 Flashing details. Provide flashing details on the building plans which comply with accepted industry standards or manufacturer’s instructions. Details are shown on house plans at all of the following locations:

  1. Around windows and doors.

  2. Roof valleys.

  3. Deck connections to the structure.

  4. Roof-to-wall intersections.

  5. Chimneys to roof intersections.

  6. Drip caps above windows and doors with architectural projections.

  Note: Reference details may be found in the Residential Sheet Metal Guidelines published by the Sheet Metal and Air Conditioning Contractors’ National Association Inc.

  A4.407.4 Material protection. Protect building materials delivered to the construction site from rain and other sources of moisture.

  A4.407.5 Ice and water barriers. In Climate Zone 16, an ice and water barrier is installed at valley, eaves and wall to roof intersections. The ice and water barrier shall extend at least 24 inches inside the exterior wall line or as specified by the manufacturer’s installation instructions.

• CALGreen § 1603.4 Medium relevance — show source text

  locking devices,
  and verify operation.|After initial installation and
  every 12 months thereafter| |
  
  Inspect caution labels and
  marking.|After initial installation and
  every 12 months thereafter| |
  
  Cross-connection inspection
  and test.*|After initial installation and
  every 12 months thereafter| |
  
  
  
  Test water quality of rainwater
  catchment systems required by
  Section 1603.4 to maintain a
  minimum water quality.|Every 12 months. After system
  renovation or repair.|

  • The cross-connection test shall be performed in the presence of the Authority Having Jurisdiction in accordance with the requirements of this chapter.

  1601.5.1 Maintenance Responsibility. The required maintenance and inspection of rainwater catchment systems shall be the responsibility of the property owner unless otherwise required by the Authority Having Jurisdiction.

  2025 CALIFORNIA PLUMBING CODE 327

  ), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.

  NONPOTABLE RAINWATER CATCHMENT SYSTEMS

  1601.6 Operation and Maintenance Manual. An operation and maintenance manual for rainwater catchment systems required to have a permit in accordance with Section 1601.3, shall be supplied to the building owner by the system designer or installer . The operating and maintenance manual shall include the following:

  (1) Diagram(s) of the entire system and the location of system components.

  (2) Instructions for operating and maintaining the system.

  (3) Instructions on maintaining the required water quality as for rainwater catchment systems .

  (4) Details startup, shutdown, and deactivating the system for maintenance, repair, or other purposes.

  (5) Applicable testing, inspection, and maintenance frequencies in accordance with Section 1601.5.

  (6) A method of contacting the installer and/or manufacturer(s).

  (7) Directions to the owner or occupant that the manual shall remain with the building throughout the life cycle of the structure.

  1601.7 Minimum Water Quality Requirements. The minimum water quality for rainwater catchment systems shall comply with the applicable water quality requirements for the intended application as determined by the Authority Having Jurisdiction. Water quality for nonpotable rainwater catchment systems shall comply with Section 1603.4. In the absence of water quality requirements for harvested rainwa- ter, Table 1603.4 shall apply.

  Exceptions:

  (1) Water treatment is not required for rainwater catchment systems used for aboveground irrigation with a maximum storage capacity of 360 gallons (1363 L).

  (2) Water treatment is not required for rainwater catchment systems used for surface, subsurface or drip irrigation. 1601.8 Material Compatibility. Rainwater catchment systems shall be constructed of materials that are compatible with the type of pipe and fitting materials, water treatment, and water conditions in the system. 1601.9 System Controls. Controls for pumps, valves, and other devices that contain mercury that come in contact with rainwater supply shall not be permitted. 1601.10 Separation Requirements. Underground rainwater catchment service piping shall be separated from the building sewer in accordance with Section 609.2.

• CALGreen § 2-8 Medium relevance — show source text

  PRECONSUMER (OR POSTINDUSTRIAL) CONTENT. [HCD] Material diverted from the waste stream during one manufacturing process, including scraps, damaged goods and excess production that is reclaimed and used in another manufacturing process. Excluded is reutilization of materials such as rework, regrind or scrap generated in a process and capable of being reclaimed within the same process that generated those wastes.

  PROCESS. [CEC] An activity or treatment that is not related to the space conditioning, lighting, service water heating or ventilating of a building as it relates to human occupancy.

  PROCESS SPACE. A space that is thermostatically controlled to maintain a process environment temperature less than 55°F or to maintain a process environment temperature greater than 90°F for the whole space that the system serves, or that is a space with a space-conditioning system designed and controlled to be incapable of operating at temperatures above 55°F or incapable of operating at temperatures below 90°F at design conditions.

  2-8 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

  on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

  DEFINITIONS

  PRODUCT-WEIGHTED MIR (PWMIR). The sum of all weighted-MIR for all ingredients in a product subject to this article. The PWMIR is the total product reactivity expressed to hundredths of a gram of ozone formed per gram of product (excluding container and packaging).

  Note: PWMIR is calculated according to equations found in CCR, Title 17, Section 94521(a).

  PROPORTIONAL RECYCLED CONTENT (PRCM). The amount of recycled content of a material in an assembly as related to the percentage of the material in an assembly product. PRCM is derived by multiplying the percentage of each material in an assembly by the percentage of recycled content in the material.

  PSIG. Pounds per square inch, gauge.

  RAINWATER. Precipitation on any public or private parcel that has not entered an offsite storm drain system or channel, a flood control channel, or any other stream channel, and has not previously been put to beneficial use.

  RAINWATER CATCHMENT SYSTEM. A facility designed to capture, retain and store rainwater flowing off a building, parking lot, or any other manmade impervious surface for subsequent onsite use. Rainwater catchment system is also known as “Rainwater Harvesting System” or “Rainwater Capture System.”

  REACTIVE ORGANIC COMPOUND (ROC). Any compound that has the potential, once emitted, to contribute to ozone formation in the troposphere.

  RECLAIMED (RECYCLED) WATER. Nonpotable water that meets California State Water Resources Control Board statewide uniform criteria for disinfected tertiary recycled water. Reclaimed (recycled) water is also known as “recycled water” or “reclaimed water.”

  RECOVERED ENERGY. [CEC] The energy used in a building that (1) is recovered from space conditioning, service water heating, lighting, or process equipment after the energy has performed its original function; (2) provides space conditioning, service water heating, or lighting; and (3) would otherwise be wasted.

  RECOVERED ENERGY, ON-SITE. [CEC] The recovered energy that is captured at the building site.