CALGreen · California Green Building Standards Code (CALGreen)

What does 'graywater' mean and where does CALGreen apply it?

Graywater in CALGreen (see **§ 202**) is untreated wastewater from bathroom and laundry fixtures (not toilets, kitchen sinks, or dishwashers). CALGreen uses that definition in its voluntary residential and nonresidential reuse measures (Appendix A4/A5) and points to the California Plumbing Code for actual system design, permitting, and installation; nonresidential system scope falls under BSC‑CG enforcement.

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Last reviewed: July 6, 2026

What the code requires — 2–4 sentences

GRAYWATER is defined in § 202 as “untreated wastewater” that has not been contaminated by toilet discharge or infectious bodily wastes, and specifically includes wastewater from bathtubs, showers, bathroom washbasins, clothes washing machines and laundry tubs but excludes wastewater from kitchen sinks or dishwashers. § 202 is the controlling definition that CALGreen uses when it refers to graywater throughout the code and appendices.

CALGreen applies that definition to: (1) its voluntary residential and nonresidential water‑reuse measures (see Appendix A4 and A5), and (2) the scope for graywater system construction/installation in occupancies identified by the Building Standards Commission (BSC‑CG). Where CALGreen points to system design, it defers to the California Plumbing Code.

The single most important point: Graywater in CALGreen means untreated wastewater from bathroom and laundry fixtures (not toilets, kitchen sinks, or dishwashers) and that definition in § 202 determines which discharges are eligible for on‑site reuse under CALGreen.

Requirements in detail

Key definition (controlling)

  • Defined term: GRAYWATER — § 202. Text summary: untreated wastewater not from toilets or infectious wastes; includes bathtubs, showers, bathroom washbasins, clothes washers and laundry tubs; excludes kitchen sinks and dishwashers.

Where CALGreen applies the definition

  • Appendix A4 (residential voluntary measures) includes graywater piping and rainwater/graywater options (A4.305.1, A4.304.2).
  • Appendix A5 (nonresidential voluntary measures) specifically recommends installing graywater collection for subsurface irrigation (A5.304.8) and points users to the Plumbing Code for system compliance (A5.305.1).
  • The Building Standards Commission scope (BSC‑CG) identifies graywater systems (construction/installation/alteration) for nonresidential occupancies as within CALGreen’s purview.

Decision‑relevant table

Decision factor What matters / value Code Reference
What counts as graywater (included sources) Bathtubs, showers, bathroom washbasins, clothes washing machines, laundry tubs § 202 —
What is explicitly excluded Kitchen sinks, dishwashers, and any toilet discharge or infectious bodily wastes § 202 —
Where CALGreen recommends reuse actions (residential voluntary) Alternative piping / graywater for irrigation and potable‑elimination options A4.305.1, A4.304.2 —
Where CALGreen recommends reuse actions (nonresidential voluntary) Install graywater collection for onsite subsurface irrigation A5.304.8 —
Who sets technical system rules CALGreen defers to the California Plumbing Code for design, installation, and treatment requirements See A4/A5 references to the Plumbing Code —
Which occupancies are included under BSC‑CG for graywater systems Nonresidential occupancies where no other state agency has authority (construction/installation/alteration) § 103.1 (BSC‑CG) —

Permit / enforcement notes

  • CALGreen identifies graywater systems in the scope of state agencies (BSC‑CG and HCD/DWR references) but instructs that system details and compliance are governed by the Plumbing Code and the appropriate enforcing agency for the occupancy. See CALGreen’s administrative scoping.

Exceptions & special cases

  • The definition in § 202 makes a categorical exclusion for kitchen sinks and dishwashers — wastewater from these fixtures is not graywater for CALGreen purposes.
  • CALGreen’s Appendix measures (A4/A5) are voluntary; a local jurisdiction may adopt them or require them by local ordinance. Appendix measures point to the Plumbing Code for technical compliance (not a full code text in CALGreen).
  • For nonresidential projects, CALGreen explicitly lists graywater system construction/installation/alteration under BSC‑CG scope — local/state enforcing agency applies depending on occupancy.

Common mistakes

  • Assuming all “used water” is graywater — remember toilet discharges, kitchen sink and dishwasher wastewater are excluded by § 202.
  • Treating CALGreen appendices as technical plumbing rules — A4/A5 often point to the California Plumbing Code for the actual system design and installation requirements.
  • Applying the same enforcement path to all occupancies — BSC‑CG and HCD/DWR roles differ by building type; check CALGreen’s scoping (Sections 101–106) for the enforcing agency.
  • Forgetting that many Appendix measures are voluntary unless adopted locally — verify local adoption before assuming a requirement.

Worked example — concrete scenario

A homeowner plans to collect water from two showers and one clothes washing machine to irrigate a small landscape bed via a subsurface system.

  • Step 1 — Are those sources graywater? Yes. Showers and clothes washing machines are listed as graywater sources in § 202, so their discharge is eligible under CALGreen’s definition.
  • Step 2 — Does CALGreen allow using that graywater for irrigation? CALGreen’s appendices recommend onsite graywater collection for subsurface irrigation (see A5.304.8 for nonresidential voluntary guidance and A4.305.1 for residential voluntary guidance) but rely on the California Plumbing Code for system design and safety. You must follow the Plumbing Code and local permitting.
  • Step 3 — Practical note: calculate expected daily volume (example only — fixture flows are not specified in CALGreen). If the washer produces ~40 gallons per load and showers together add ~40 gallons/day, you would have ~80 gallons/day of graywater to distribute — check plumbing‑code sizing, irrigation application rate, and permitting before construction. (Flow numbers are illustrative and not prescribed in CALGreen.)

Related provisions

  • § 202 — Definition of GRAYWATER (controlling definition).
  • § 101.3.1 — Scope note: graywater systems regulated by DWR and HCD.
  • § 103.1 (BSC‑CG) — Graywater systems for nonresidential occupancies (construction/installation/alteration).
  • A4.304.2 — Potable water elimination methods include use of graywater (residential voluntary).
  • A4.305.1 — Residential voluntary provision: alternative piping/graywater for irrigation; see Plumbing Code for installation.
  • A5.304.8 — Nonresidential voluntary provision: install a graywater irrigation system for onsite subsurface irrigation.
  • A5.305.1 — Nonpotable water systems must comply with the California Plumbing Code.

Code references

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

  • CALGreen § 17922.12 High relevance — show source text

    GRAYWATER. Pursuant to Health and Safety Code Section 17922.12, “graywater” means untreated wastewater that has not been contaminated by any toilet discharge, has not been affected by infectious, contaminated or unhealthy bodily wastes, and does not present a threat from contamination by unhealthful processing, manufacturing or operating wastes. “Graywater” includes, but is not limited to, wastewater from bathtubs, showers, bathroom washbasins, clothes washing machines and laundry tubs, but does not include wastewater from kitchen sinks or dishwashers.

    Note: For the purpose of applying the standards contained in this code, “Graywater,” as defined above, has the same meaning as “gray water,” “grey water,” and “greywater.”

    GREEN BUILDING. A holistic approach to design, construction and demolition that minimizes the building’s impact on the environment, the occupants and the community.

    GREENFIELDS. Sites that are not previously developed or graded and remain in a natural state, able to support agriculture, open space or habitat.

    Note: Previously developed sites are those that previously contained buildings, roadways or parking lots or were graded or altered by direct human activities.

    GREYFIELD SITE. Any site previously developed with at least 50 percent of the surface area covered with impervious material.

    HALON. Any of a class of chemical compounds derived from hydrocarbons by replacing one or more hydrogen atoms with bromine atoms, and other hydrogen atoms with other halogen atoms (chlorine, fluorine, iodine).

    HAZARDOUS WASTE.

    (a) A waste, defined as a “hazardous waste” in accordance with Section 25117 of the Health and Safety Code, or a combination of wastes, which because of its quantity, concentration or physical, chemical or infectious characteristics may do either of the following: (1) Cause, or significantly contribute to, an increase in mortality or an increase in serious irreversible, or incapacitating reversible, illness. (2) Pose a substantial present or potential hazard to human health or environment when improperly treated, stored, transported or disposed of, or otherwise managed. (b) Unless expressly provided otherwise, “hazardous waste” includes extremely hazardous waste and acutely hazardous

    waste.

    HEAT ISLAND EFFECT. “Heat island effect” and “urban heat islands” refer to measurable elevated temperatures in developed areas as compared to more rural surroundings. Temperatures in developed areas are affected by absorption of heat by hardscapes and radiation of heat into surrounding areas resulting in local climate changes. Heat islands are influenced by geographic location and by local weather patterns, with effects changing on a daily or seasonal basis.

    HIGH-GWP REFRIGERANT. A compound used as a heat transfer fluid or gas that is: (A) a chlorofluorocarbon, a hydrochlorofluorocarbon, a hydrofluorocarbon, a perfluorocarbon, or any compound or blend of compounds, with a GWP value equal to or greater than 150, or (B) any ozone depleting substance as defined in Title 40 of the Code of Federal Regulations, Part 82, §82.3 (as amended March 10, 2009).

    HIGH-RISE RESIDENTIAL BUILDING. For the purposes of CALGreen, any building that is of Occupancy Group R and is four stories or greater in height.

  • CALGreen § 2-5 High relevance — show source text

    GEOTHERMAL. [CEC] Renewable energy generated by deep-earth water or steam.

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    DEFINITIONS

    GLASS, ACID ETCHED. [BSC-CG] Glass with hydrofluoric acid washed across the entire first surface (surface 1), which can result in a variety of patterns as visual markers.

    GLASS, FRITTED. [BSC-CG] Glass manufactured with ceramic-based paint applied in various patterns as visual markers.

    GLASS SURFACE. [BSC-CG] The exterior surface is the first surface (surface 1) where visual markers are usually applied, and subsequent interior surfaces are numbered in ascending order.

    GLOBAL WARMING POTENTIAL (GWP). The radiative forcing impact of one mass-based unit of a given greenhouse gas relative to an equivalent unit of carbon dioxide over a given period of time. Carbon dioxide is the reference compound with a GWP of one.

    GLOBAL WARMING POTENTIAL VALUE (GWP VALUE). The 100-year GWP value published by the Intergovernmental Panel on Climate Change (IPCC) in either its Second Assessment Report (SAR) (IPCC, 1995); or its Fourth Assessment A-3 Report (AR4) (IPCC, 2007). The SAR GWP values are found in column “SAR (100-yr)” of Table 2.14.; the AR4 GWP values are found in column “100 yr” of Table 2.14.

    GRAYWATER. Pursuant to Health and Safety Code Section 17922.12, “graywater” means untreated wastewater that has not been contaminated by any toilet discharge, has not been affected by infectious, contaminated or unhealthy bodily wastes, and does not present a threat from contamination by unhealthful processing, manufacturing or operating wastes. “Graywater” includes, but is not limited to, wastewater from bathtubs, showers, bathroom washbasins, clothes washing machines and laundry tubs, but does not include wastewater from kitchen sinks or dishwashers.

    Note: For the purpose of applying the standards contained in this code, “Graywater,” as defined above, has the same meaning as “gray water,” “grey water,” and “greywater.”

    GREEN BUILDING. A holistic approach to design, construction and demolition that minimizes the building’s impact on the environment, the occupants and the community.

    GREENFIELDS. Sites that are not previously developed or graded and remain in a natural state, able to support agriculture, open space or habitat.

    Note: Previously developed sites are those that previously contained buildings, roadways or parking lots or were graded or altered by direct human activities.

    GREYFIELD SITE. Any site previously developed with at least 50 percent of the surface area covered with impervious material.

    HALON. Any of a class of chemical compounds derived from hydrocarbons by replacing one or more hydrogen atoms with bromine atoms, and other hydrogen atoms with other halogen atoms (chlorine, fluorine, iodine).

    HAZARDOUS WASTE.

  • CALGreen § 3.3.68.4 High relevance — show source text

    Minimal Sedation (Anxiolysis). A drug-induced state during which patients respond normally to verbal commands. Although cognitive function and coordination may be impaired, ventilatory and cardiovascular functions are unaffected. [NFPA 99:3.3.68.4]

    Moderate Sedation/Analgesia (Conscious Seda- tion). A drug-induced depression of consciousness during which patients respond purposefully to verbal commands, either alone or accompanied by light tactile stimulation. No interventions are required to maintain a patient airway, and spontaneous ventilation is adequate. Cardiovascular function is usually maintained. [NFPA 99:3.3.68.3]

    Grade. The slope or fall of a line of pipe in reference to a horizontal plane. In drainage, it is usually expressed as the fall in a fraction of an inch (mm) or percentage slope per foot (meter) length of pipe.

    Gravity Grease Interceptor. A plumbing appurtenance or appliance that is installed in a sanitary drainage system to intercept nonpetroleum fats, oils, and greases (FOG) from a wastewater discharge and is identified by volume, 30 minute retention time, baffle(s), not less than two compartments, a total volume of not less than 300 gallons (1135 L), and gravity separation. [These interceptors comply with the requirements of Chapter 10 or are designed by a registered design professional.] Gravity grease interceptors are generally installed outside.

    Graywater. [BSC-CG & HCD 1] Pursuant to Health and Safety Code Section 17922.12, “graywater” means untreated wastewater that has not been contaminated by any toilet dis- charge, has not been affected by infectious, contaminated, or unhealthy bodily wastes, and does not present a threat from contamination by unhealthful processing, manufacturing, or operating wastes. "Graywater" includes, but is not limited to, wastewater from bathtubs, showers, bathroom washbasins, clothes washing machines, and laundry tubs, but does not include wastewater from kitchen sinks or dishwashers.

    Note: For the purpose of applying the standards contained in this code, “Graywater” as defined above, has the same meaning as “gray water”, “grey water”, and “greywater”.

    Gray Water System. [BSC-CG & HCD 1] A system designed to collect gray water on-site for reuse or distribution to an irrigation or disposal field. A gray water system may include, on-site treated nonpotable water devices or equip- ment, tanks, valves, filters, pumps or other appurtenances along with piping and receiving landscape.

    Grease Interceptor. A plumbing appurtenance or appliance that is installed in a sanitary drainage system to intercept nonpetroleum fats, oil, and greases (FOG) from a wastewater discharge.

    Grease Removal Device (GRD). A hydromechanical grease interceptor that automatically, mechanically removes non-petroleum fats, oils and grease (FOG) from the interceptor, the control of which are either automatic or manually initiated.

    Grounding Electrode. A conducting object through which a direct connection to earth is established. [NFPA 70:100 (Part I)]

    Groundwater. Water that exists beneath the earth’s surface.

  • CALGreen § 102.1 Medium relevance — show source text
    1. The application checklist identifies which measures are required by this code and allows users to check off which voluntary items have been selected to meet voluntary tier levels if desired or mandated by a city, county, or city and county.

    SECTION 102—CONSTRUCTION DOCUMENTS AND INSTALLATION VERIFICATION

    102.1 Submittal documents. Construction documents and other data shall be submitted in one or more sets with each application for a permit. Where special conditions exist, the enforcing agency is authorized to require additional construction documents to be prepared by a licensed design professional and may be submitted separately.

    Exception: The enforcing agency is authorized to waive the submission of construction documents and other data not required to be prepared by a licensed design professional.

    102.2 Information on construction documents. Construction documents shall be of sufficient clarity to indicate the location, nature and scope of the proposed green building feature and show that it will conform to the provisions of this code, the California Building Standards Code and other relevant laws, ordinances, rules and regulations as determined by the enforcing agency.

    102.3 Verification. Documentation of conformance for applicable green building measures shall be provided to the enforcing agency. Alternate methods of documentation shall be acceptable when the enforcing agency finds that the proposed alternate documentation is satisfactory to demonstrate substantial conformance with the intent of the proposed green building measure.

    [HCD] Documentation of conformance for applicable green building measures shall be provided to the enforcing agency. All projects shall submit a completed Residential Occupancies Application Checklist that includes Chapter 4 residential mandatory measures and Tier 1 or Tier 2, as applicable. References to the measure-specific documentation used to show compliance shall be included. Alternate methods of documentation shall be acceptable when the enforcing agency finds that the proposed alternate documentation is satisfactory to demonstrate substantial conformance with the intent of the proposed green building measure.

    Note: HCD’s Residential Occupancies Application Checklist that includes the minimum criteria for documentation is available at: http://www.hcd.ca.gov/building-standards/calgreen/cal-green-forms.shtml.

    SECTION 103—BUILDING STANDARDS COMMISSION

    103.1 BSC-CG. Specific scope of application of the agency responsible for enforcement, the enforcement agency, and the specific authority to adopt and enforce such provisions of this code, unless otherwise stated.

    1. Application— All occupancies where no state agency has the authority to adopt green building standards applicable to those occupancies. Enforcing agency— State or local agency specified by the applicable provisions of law. Authority cited— Health and Safety Code Sections 18930.5(a), 18938 and 18940.5. Reference— Health and Safety Code, Division 13, Part 2.5, commencing with Section 18901.
    2. Graywater systems. The construction, installation and alteration of graywater systems for indoor and outdoor uses in nonresidential occupancies. Application— All occupancies where no state agency has the authority to adopt green building standards applicable to those occupancies. Enforcing agency— State or local agency specified by the applicable provisions of law. Authority cited— Health and Safety Code Section 18941.8. Reference— Health and Safety Code Section 18941.8.

    103.1.1 Adopting agency identification. The provisions of this code applicable to buildings identified in this section will be identified in the Matrix Adoption Tables under the acronym BSC-CG.

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    ADMINISTRATION

  • CALGreen § 103.1 Medium relevance — show source text

    SECTION 103—BUILDING STANDARDS COMMISSION

    103.1 BSC-CG. Specific scope of application of the agency responsible for enforcement, the enforcement agency, and the specific authority to adopt and enforce such provisions of this code, unless otherwise stated.

    1. Application— All occupancies where no state agency has the authority to adopt green building standards applicable to those occupancies. Enforcing agency— State or local agency specified by the applicable provisions of law. Authority cited— Health and Safety Code Sections 18930.5(a), 18938 and 18940.5. Reference— Health and Safety Code, Division 13, Part 2.5, commencing with Section 18901.
    2. Graywater systems. The construction, installation and alteration of graywater systems for indoor and outdoor uses in nonresidential occupancies. Application— All occupancies where no state agency has the authority to adopt green building standards applicable to those occupancies. Enforcing agency— State or local agency specified by the applicable provisions of law. Authority cited— Health and Safety Code Section 18941.8. Reference— Health and Safety Code Section 18941.8.

    103.1.1 Adopting agency identification. The provisions of this code applicable to buildings identified in this section will be identified in the Matrix Adoption Tables under the acronym BSC-CG.

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    ADMINISTRATION

    SECTION 104—DEPARTMENT OF HOUSING AND COMMUNITY DEVELOPMENT

    104.1 Scope. Specific scope of application of the agency responsible for enforcement, the enforcement agency and the specific authority to adopt and enforce such provisions of this code, unless otherwise stated.

    1. Housing construction. Application— Hotels, motels, lodging houses, apartments, dwellings, dormitories, condominiums, shelters for homeless persons, congregate residences, employee housing, factory-built housing and other types of dwellings containing sleeping accommodations with or without common toilet or cooking facilities including accessory buildings, facilities and uses thereto. Enforcing agency— Local building department or the Department of Housing and Community Development. Authority cited— Health and Safety Code Sections 17040, 17920.9, 17921, 17921.5, 17921.6, 17921.10, 17922, 17922.6, 17922.12, 17922.14, 17922.15, 17926, 17927, 17928, 17958.12, 18938.3, 18944.11 and 19990; and Government Code Section

    12955.1.

  • CALGreen § 304.8 Medium relevance — show source text

    Exception: Area of the building footprint is excluded from the calculation.

    A5.304.8 Graywater irrigation system. Install a graywater collection system for onsite subsurface irrigation using graywater collected from bathtubs, showers, bathroom wash basins and laundry water. See California Plumbing Code.

    SECTION A5.305—WATER REUSE

    A5.305.1 Nonpotable water systems. Nonpotable water systems for indoor and outdoor use shall comply with the current edition of the California Plumbing Code.

    A5.305.2 Irrigation systems. Irrigation systems regulated by a local water efficient landscape ordinance or by the California Department of Water Resources Model Water Efficient Landscape Ordinance (MWELO) shall use recycled water.

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    CALIFORNIA GREEN BUILDING STANDARDS CODE – MATRIX ADOPTION TABLE

    APPENDIX A5 – NONRESIDENTIAL VOLUNTARY MEASURES

    DIVISION A5.4 – MATERIAL CONSERVATION AND RESOURCE EFFICIENCY

    (Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)

    Adopting agency BSC BSC-
    CG    		 SFM HCD Col6 Col7 DSA Col9 OSHPD Col11 Col12 Col13 Col14 Col15 BSCC DPH AGR DWR CEC CA SL SLC
    Adopting agency BSC BSC-
    CG    		 SFM 1 2 1/AC AC SS 1 1R 2 3 4 5 5 5 5 5 5 5 5 5
    Adopt entire CA chapter X
    Adopt entire chapter as
    amended (amended
    sections listed below)
    Adopt only those sections
    that are listed below
    Chapter/Section

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    A5 NONRESIDENTIAL VOLUNTARY MEASURES

    DIVISION A5.4 – MATERIAL CONSERVATION AND RESOURCE EFFICIENCY

    SECTION A5.401—GENERAL

  • CALGreen § 1.2.1.1 Medium relevance — show source text

    1.2.1.1 State building. For purposes of this code, a “state building” is a structure for which a state agency or state entity has authority to construct, alter, enlarge, replace, repair or demolish.

    1.2.1.2 Enforcement. [CSU, UC, Judicial Council and California Department of Corrections and Rehabilitation] State agencies or state entities authorized to construct state buildings may appoint a building official who is responsible to the agency for enforcement of the provisions of the California Building Standards Code.

    Exception: State buildings regulated by other sections of this code remain the enforcement responsibility of the designated entities.

    1.2.1.3 Enforcement. Reserved for DGS.

    1.2.1.4 Adopting agency identification. The provisions of this code applicable to buildings identified in this section will be identified in the Matrix Adoption Tables under the acronym BSC .

    1.2.2 BSC-CG. Specific scope of application of the agency responsible for enforcement, the enforcement agency and the specific authority to adopt and enforce such provisions of this code, unless otherwise stated. 1. Green building standards for nonresidential occupancies.

    Application— All occupancies where no state agency has the authority to adopt green building standards applicable to those occupancies.

    Enforcing agency— State or local agency specified by the applicable provisions of law.

    Authority cited— Health and Safety Code Sections 18930.5(a), 18938 and 18940.5.

    Reference— Health and Safety Code, Division 13, Part 2.5, commencing with Section 18901. 2. Graywater systems for nonresidential occupancies.

    Application— The construction, installation and alteration of graywater systems for indoor and outdoor uses in nonresidential occupancies.

    Enforcing agency— State or local agency specified by the applicable provisions of law.

    Authority cited— Health & Safety Code Section 18941.8.

    Reference— Health & Safety Code Section 18941.8.

    1.2.2.1 Adopting agency identification. The provisions of this code applicable to buildings identified in this section will be identified in the Matrix Adoption Tables under the acronym BSC-CG .

    1.2.3 Alternative materials, design and methods of construction and equipment. The provisions of this code are not intended to prevent the installation of any material or to prohibit any design or method of construction not specifically prescribed by this code, provided that any such alternative has been approved. An alternative material, design or method of construction shall be approved where the building official finds that the proposed design is satisfactory and complies with the intent of the provisions of this code, and that the material, method or work offered is, for the purpose intended, at least the equivalent of that prescribed in this code in quality, strength, effectiveness, fire resistance, durability and safety.

    1.2.3.1 Research reports. Supporting data, where necessary to assist in the approval of materials or assemblies not specifically provided for in this code, shall consist of valid research reports from approved sources.

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  • CALGreen § 301.1 Medium 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 § 303.4 Medium relevance — show source text

    APPENDIX A5 — NONRESIDENTIAL VOLUNTARY MEASURES

    A5.303.4 Water conserving plumbing fixtures and fittings.

    A5.303.4.1 Nonwater urinals. Nonwater urinals with drain cleansing action are installed in accordance with the California Plumbing Code .

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

    A5.303.5 Dual plumbing. New buildings and facilities shall be dual plumbed for potable and recycled water systems for toilet flushing when recycled water is available as determined by the enforcement authority.

    SECTION A5.304—OUTDOOR WATER USE

    A5.304.1 Reserved.

    A5.304.2 Outdoor water use. For new water service not subject to the provisions of Water Code Section 535, separate meters or submeters shall be installed for indoor and outdoor potable water use for landscaped areas of at least 500 square feet but not more than 1,000 square feet.

    A5.304.6 Restoration of areas disturbed by construction. Restore all landscape areas disturbed during construction by planting with local adaptive and/or noninvasive vegetation.

    A5.304.7 Previously developed sites. On previously developed or graded sites, restore or protect at least 50 percent of the site area with adaptive and/or noninvasive vegetation. Projects complying with Section A5.106.3, Item 3 may apply vegetated roof surface to this calculation if the roof plants meet the definition of adaptive and noninvasive.

    Exception: Area of the building footprint is excluded from the calculation.

    A5.304.8 Graywater irrigation system. Install a graywater collection system for onsite subsurface irrigation using graywater collected from bathtubs, showers, bathroom wash basins and laundry water. See California Plumbing Code.

    SECTION A5.305—WATER REUSE

    A5.305.1 Nonpotable water systems. Nonpotable water systems for indoor and outdoor use shall comply with the current edition of the California Plumbing Code.

    A5.305.2 Irrigation systems. Irrigation systems regulated by a local water efficient landscape ordinance or by the California Department of Water Resources Model Water Efficient Landscape Ordinance (MWELO) shall use recycled water.

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    APPENDIX A5-22 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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    CALIFORNIA GREEN BUILDING STANDARDS CODE – MATRIX ADOPTION TABLE

    APPENDIX A5 – NONRESIDENTIAL VOLUNTARY MEASURES

    DIVISION A5.4 – MATERIAL CONSERVATION AND RESOURCE EFFICIENCY

    (Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)

  • CALGreen § 18934.7. Medium relevance — show source text

    Application— Building seismic retrofit standards including abating falling hazards of structural and nonstructural compo- nents and strengthening of building structures. See also Division of the State Architect.

    Enforcing agency— State or local agency specified by the applicable provisions of law.

    Authority cited— Health and Safety Code Section 16600.

    Reference— Health and Safety Code Sections 16600 through 16604. 4. Unreinforced masonry-bearing wall buildings.

    Application— Minimum seismic strengthening standards for buildings specified in Appendix Chapter A1 of the California Existing Building Code, except for buildings subject to building standards adopted pursuant to Health and Safety Code (commencing) with Section 17910.

    Enforcing agency— State or local agency specified by the applicable provisions of law.

    Authority cited— Health and Safety Code Section 18934.7.

    Reference— Health and Safety Code, Division 13, Part 2.5, commencing with Section 18901.

    1.2.1.1 State building. For purposes of this code, a “state building” is a structure for which a state agency or state entity has author- ity to construct, alter, enlarge, replace, repair or demolish.

    1.2.1.2 Enforcement. [CSU, UC, Judicial Council and California Department of Corrections and Rehabilitation] State agencies or state entities authorized to construct state buildings may appoint a building official who is responsible to the agency for enforcement of the provisions of the California Building Standards Code.

    Exception: State buildings regulated by other sections of this code remain the enforcement responsibility of the designated entities.

    1.2.1.3 Enforcement. Reserved for DGS.

    1.2.1.4 Adopting agency identification. The provisions of this code applicable to buildings identified in this section will be identified in the Matrix Adoption Tables under the acronym BSC .

    1.2.2 BSC-CG. Specific scope of application of the agency responsible for enforcement, the enforcement agency and the specific author- ity to adopt and enforce such provisions of this code, unless otherwise stated. 1. Green buildings standards for nonresidential occupancies.

    — Application All occupancies where no state agency has the authority to adopt green building standards applicable to those occupancies.

    — Enforcing agency State or local agency specified by the applicable provisions of law.

    — Authority cited Health and Safety Code Sections 18930.5(a), 18938 and 18940.5.

    Reference — Health and Safety Code, Division 13, Part 2.5, commencing with Section 18901. 2. Graywater systems for nonresidential occupancies.

    — Application The construction, installation and alteration of graywater systems for indoor and outdoor uses in nonresiden- tial occupancies.

    — Enforcing agency State or local agency specified by the applicable provisions of law.

    — Authority cited Health and Safety Code Section 18941.8.

  • CALGreen § 303.5 Medium 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

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

  • CALGreen § 209.0 Medium relevance — show source text

    – G –

    GANG OR GROUP SHOWERS . . . . . . .209.0, 408.4, 408.8 GARBAGE GRINDER . . . . . . . . .(see Food waste disposer)

    GRADE

    Building sewer . . . . . . . . . . . . . . . . . . . . . . . . . . . .718.1

    Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .209.0

    Horizontal drainage . . . . . . . . . . . . . . . . . . . . . . . .708.0 GRAVITY DRAINAGE REQUIRED . . . . . . . . . . . . . . .709.0

    GRAYWATER, DEFINITION . . . . . . . . . . . . . . . . . . . . . . 209.0

    GRAY WATER SYSTEMS

    Alternate water sources . . . . . . . . . . . . . . . . . . .601.3.3

    Alternate water source testing, inspection, and maintenance frequency . . . . . . . . . . .Table 1501.5 Components . . . . . . . . . . . . . . . . . . . . . . . . . . . .1503.9 Daily discharge . . . . . . . . . . . . . . . . . . . . . . . .1503.8.3

    Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .209.0

    Gray water systems . . . . . . . . . . . . . . . . . . . . . . .1503.0 Inspection and testing . . . . . . . . . . . . . . . . . . . . .1502.0 Operation and maintenance manual . . . . . . . . . .1501.6 GREASE INTERCEPTORS . . . . . .1014.0, 1014.1B, 1014.1C

    Approved standards . . . . . . . . . . . . . . . . . . . . . . .1014.1

    Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .209.0

    Capacity . . . . . . . . . . . . . . . . . .1014.2.1, Table 1014.2.1 Gravity-type . . . . . . . . . . . . . . . . .1014.3, Table 1014.3.6 Hydromechanical-type . . . . . . . . . . . . . . . . . . . . .1014.2 Not required . . . . . . . . . . . . . . . . . . . . . . . . . . . .1014.1.3 Required . . . . . . . . . . . . . . . . . .1010.1, 1014.1, H 101.3

    GRINDER PUMPS . . . . . . . . . . . . . . . . . . . . . . . . . . .710.12

Frequently asked questions

What exactly is excluded from the CALGreen definition of graywater?

Wastewater from kitchen sinks and dishwashers and any toilet discharges or infectious bodily wastes are excluded by § 202.

If my jurisdiction adopted Appendix A measures, do I still need a plumbing permit?

Yes. CALGreen appendices point to the California Plumbing Code for design and installation; local permits and the enforcing agency still apply.

Does CALGreen itself give detailed treatment or plumbing specs for graywater systems?

No. CALGreen defines GRAYWATER and includes voluntary measures recommending reuse strategies, but it directs users to the California Plumbing Code for system design, testing and maintenance details.

Are graywater measures mandatory statewide?

Appendix A measures are voluntary in CALGreen unless a local jurisdiction adopts them; check local ordinance/adoption.

Who enforces graywater system rules for nonresidential buildings?

CALGreen lists graywater systems for nonresidential occupancies under BSC‑CG scope; the specific enforcing agency depends on the building type and applicable state/local authority.

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California Green Building Standards Code (CALGreen)