CALGreen · California Green Building Standards Code (CALGreen)

Indoor potable water reduction targets and fixture requirements

CALGreen Tier 1 requires either that each indoor fixture meet the maximum flow rates listed in Table A5.303.2.3.1 (prescriptive path) or that the project show a 12% reduction in total indoor potable water use from the baseline using Worksheet WS‑1 (performance path); nonpotable systems and certain aerator substitutions are allowed but must follow the California Plumbing Code and appendix rules.

Ask a question free See coverage

Last reviewed: July 6, 2026

What the code requires — 2-4 sentences

The code requires a 12‑percent reduction in indoor potable water use for the Tier 1 voluntary measure. Compliance may be shown either by a prescriptive method (each fixture meets maximum flow limits in the table) or a performance method (a calculation showing a 12% reduction from the building “water use baseline”) under § 5.303.2.3.1 . The prescriptive flow limits are set in Table A5.303.2.3.1; the performance path uses the baseline worksheet (WS‑1) and supporting tables to demonstrate the required reduction .

The single most important rule: either meet each fixture’s maximum flow shown in Table A5.303.2.3.1, or show a whole‑building 12‑percent potable water reduction from the baseline using Worksheet WS‑1 and the reduction calculation in the appendices (compliance per § 5.303.2.3.1) .

Requirements in detail

Scope and the two compliance routes

  • Tier 1 — 12‑percent savings (mandatory for Tier 1 elective): A schedule of fixtures demonstrating a 12‑percent reduction is required per § 5.303.2.3.1 .
  • Two permitted methods under § 5.303.2.3.1:
    • Prescriptive method: Each plumbing fixture/fitting shall not exceed the maximum flow rates listed in Table A5.303.2.3.1 (this satisfies the 12% requirement) .
    • Performance method: Provide a calculation demonstrating 12% reduction in the building water use baseline established in Table A5.303.2.2, using Worksheet WS‑1 and the reduction worksheets in Chapter 8 .

Key definitions (first mention bolded)

  • Tier 1 — the voluntary CALGreen tier that requires the 12% indoor potable water reduction when selected (see Appendix A5) .
  • Prescriptive method — meet the maximum fixture flow rates in Table A5.303.2.3.1 for each installed fixture .
  • Performance method — demonstrate a 12% reduction vs. the building “water use baseline” using the provided worksheets (WS‑1/WS‑2) .
  • Worksheet WS‑1 — the baseline water‑use worksheet (Chapter 8) used to calculate the building baseline and inputs for the performance method .

Prescriptive flow rates — decision table

Fixture type Baseline flow rate (reference) Maximum flow rate to meet Tier 1 prescriptive Code Reference
Showerheads 1.8 gpm @ 80 psi 1.6 gpm @ 80 psi § 5.303.2.3.1; Table A5.303.2.3.1
Lavatory faucets (nonresidential) 0.5 gpm @ 60 psi 0.35 gpm @ 60 psi § 5.303.2.3.1; Table A5.303.2.3.1
Kitchen faucets (nonresidential) 1.8 gpm @ 60 psi 1.6 gpm @ 60 psi § 5.303.2.3.1; Table A5.303.2.3.1
Wash fountains 1.8 gpm / 20 [rim space] @ 60 psi 1.6 gpm / 20 [rim space] § 5.303.2.3.1; Table A5.303.2.3.1
Water closets (various types) Baseline 1.28 gpf 1.12 gpf (effective) § 5.303.2.3.1; Table A5.303.2.3.1
Urinals Floor 0.5 / Wall 0.125 gpf 0.44 / 0.11 gpf (table values) § 5.303.2.3.1; Table A5.303.2.3.1

Notes about the table:

  • These maximums are the prescriptive path that satisfies the 12‑percent objective in § 5.303.2.3.1; use the table values literally when following the prescriptive route .
  • Where complying faucets are not available, the code permits using aerators or other means (example: aerators rated at 0.35 gpm) to achieve required reductions—see table footnotes and appendix notes .

Performance method mechanics

  • Establish the building water use baseline per Table A5.303.2.2 and Worksheet WS‑1; baseline calculation inputs (flow rates, durations, daily uses, occupant counts) are provided in WS‑1 and Chapter 8 .
  • Demonstrate a 12‑percent reduction relative to that baseline using a schedule of fixtures and/or nonpotable substitution, and submit the calculation and supporting worksheet(s) as evidence under § 5.303.2.3.1 .

Exceptions & special cases

  • Nonpotable sources: Treated nonpotable water (captured rainwater, treated graywater, recycled water) may be included in calculations for the 12%, 20%, or 25% reductions, provided those systems comply with the California Plumbing Code—see A5.303.2.3.4 (related appendix) .
  • When complying fixtures are unavailable: The appendix notes permit alternate means (for example, 0.35 gpm aerators for faucets) if product availability prevents a prescriptive fixture install—see table footnotes in the appendix .
  • Occupant/usage adjustments: WS‑1 includes occupancy and daily‑use notes (for instance, increase the daily use number to 3 if urinals are not installed in a room); follow those guidance notes when building the baseline calculation .
  • Appendix vs. mandatory adoption: Appendix A5 is voluntary unless adopted locally. The Tier 1 measures (including the 12% indoor potable reduction) are required only where Appendix A5 has been adopted by the enforcing jurisdiction as part of CALGreen Tier compliance (see Appendix A5, Section A5.601 references) .

Common mistakes

  • Assuming the prescriptive table is optional: If using the prescriptive route, every fixture must meet the table maximums — you cannot mix non‑compliant fixtures and claim prescriptive compliance (use the performance route instead) .
  • Mis‑calculating the baseline: Not using Worksheet WS‑1 and Table A5.303.2.2 inputs (durations, daily uses, occupant factors) leads to incorrect baselines; always use WS‑1 values and notes for the performance path .
  • Ignoring footnotes/availability notes: Some table entries include footnotes that permit aerators or exceptions when compliant fixtures aren’t available—read the table footnotes before substituting products .
  • Forgetting nonpotable credit rules: If counting nonpotable supply toward the reduction, make sure the nonpotable supply is sized and installed in compliance with the California Plumbing Code; otherwise the allowance is not valid .

Worked example — prescriptive check (concrete scenario with numbers)

Scenario: Small nonresidential tenant improvement (break area + restrooms) with the following fixtures to be installed:

  • 3 lavatory faucets (nonresidential),
  • 1 kitchen/utility faucet,
  • 2 water closets, and
  • 1 urinal (wall‑mounted).

Prescriptive check per Table A5.303.2.3.1 (prescriptive path under § 5.303.2.3.1):

  • Lavatory faucets: Table baseline 0.5 gpm → maximum allowed 0.35 gpm. Install lavatory faucets with 0.35 gpm aerators or fixtures meeting that rating to comply .
  • Kitchen faucet: Table baseline 1.8 gpm → maximum allowed 1.6 gpm. Specify a kitchen faucet (or flow control device) rated ≤ 1.6 gpm @ 60 psi .
  • Water closets: Use fixtures with an effective flush ≤ 1.12 gpf (per table footnote and related entries) to meet the prescriptive limits .
  • Urinal (wall): Use a wall‑mounted urinal rated at 0.125 gpf or the table’s equivalent maximum (table lists reduced values) .

Result: If all installed fixtures meet the table maximum flow rates above, the project meets the Tier 1 prescriptive method under § 5.303.2.3.1; no whole‑building performance calculation is required in this case .

(If the project cannot source fixtures to meet one or more maximums, the owner may instead follow the performance method: compute the building baseline with WS‑1, then show a 12% reduction via a fixture schedule and/or nonpotable substitutions per § 5.303.2.3.1 and the appendix worksheets .)

Related provisions

  • § A5.303.2.3.2 — Tier 2 (20‑percent savings) elective requirements (appendix) .
  • § A5.303.2.3.3 — 25‑percent savings elective (appendix) .
  • § A5.303.2.3.4 — Use of nonpotable water systems for indoor use in the reduction calculations; must comply with California Plumbing Code (appendix) .
  • § A5.303.3 — Appliances and fixtures for commercial applications (related appliance water‑use standards) .
  • Worksheet WS‑1 (Chapter 8) — Baseline water use calculation inputs and notes; required for the performance method .
  • § 5.303.6 / Chapter 4 plumbing fixture standards — cross‑references to mandatory plumbing fixture performance and referenced standards in the California Plumbing Code and CALGreen mandatory chapters .

Code references

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

  • CALGreen § 1.12 High relevance — show source text

    Includes water closets with an effective flush rate of 1.12 gallons or less when tested per ASME A 112.19.2 and ASME A 112.19.14.
    2. See Table A5.503.2.2 for additional notes and references.
    3. Where complying faucets are unavailable, aerators rated at 0.35 gpm or other means may be used to achieve reduction.
    4. Floor-mounted urinals @ 0.5 GPF or wall-mounted urinals @ 0.125 GPF.|

    A5.303.2.3.2 Tier 2 – 20-percent savings. A schedule of plumbing fixtures and fixture fittings that will reduce the overall use of potable water within the building by 20 percent shall be provided. A calculation demonstrating a 20-percent reduction in the building “water use baseline” as established in Table A5.303.2.2 shall be provided. A5.303.2.3.3 25-percent savings. A schedule of plumbing fixtures and fixture fittings that will reduce the overall use of potable water within the building by 25 percent shall be provided. A calculation demonstrating a 25-percent reduction in the building “water use baseline” as established in Table A5.303.2.2 shall be provided. A5.303.2.3.4 Nonpotable water systems for indoor use. Utilizing nonpotable water systems (such as captured rainwater, treated graywater and recycled water) intended to supply water closets, urinals and other allowed uses, may be used in the calculations demonstrating the 12-, 20- or 25-percent reduction. The nonpotable water systems shall comply with the current edition of the California Plumbing Code.

    A5.303.3 Appliances and fixtures for commercial application. Appliances and fixtures shall meet the following:

    1. Clothes washers shall have a maximum Water Factor (WF) that will reduce the use of water by 10 percent below the California Energy Commissions’ WF standards for commercial clothes washers located in Title 20 of the California Code of Regulations.
    2. Dishwashers shall meet the following water use standards: a. Residential—ENERGY STAR.

    i. Standard Dishwashers – 4.25 gallons per cycle. ii. Compact Dishwashers – 3.5 gallons per cycle. b. Commercial—Shall be in accordance with ENERGY STAR requirements. Refer to Table A5.303.3. 3. Ice makers shall be air cooled.

    1. Food steamers shall be connectionless or boilerless – and shall consume no more than 2 gallons of water per pan per hour, including condensate water, for batch type steamers, and no more than 5 gallons of water per pan per hour, including condensate water, for cook to order steamers.
    2. The use and installation of water softeners that discharge to the community sewer system may be limited or prohibited by local agencies if certain conditions are met.
    3. Combination ovens shall use a maximum of 1.5 gallons of water per hour per pan, including condensate water.
    4. Food waste pulping systems shall use no more than 2 gpm of potable water. 7.1. Note: potable water excludes on-site graywater use, such as dishwasher discharge water.

    |TABLE A5.303.

  • CALGreen § 4-1 High relevance — show source text

    The daily use number shall be increased to three if urinals are not installed in the room.
    2. Refer to Table 4-1, Chapter 4, 2025_California Plumbing Code_, for occupant load factors.
    a. Shower use by occupants depends on the type of use of a building or portion of a building, e.g., total occupant load for a health club, but only a fraction of the occupants
    in an office building as determined by the anticipated number of users.
    b. Kitchen faucet use is determined by the occupant load of the area served by the fixture.
    3. Use worksheet WS-1 to calculate baseline water use.
    4. Floor-mounted urinals @ 0.5 GPF or wall-mounted urinals @ 0.125 GPF.|1. The daily use number shall be increased to three if urinals are not installed in the room.
    2. Refer to Table 4-1, Chapter 4, 2025_California Plumbing Code_, for occupant load factors.
    a. Shower use by occupants depends on the type of use of a building or portion of a building, e.g., total occupant load for a health club, but only a fraction of the occupants
    in an office building as determined by the anticipated number of users.
    b. Kitchen faucet use is determined by the occupant load of the area served by the fixture.
    3. Use worksheet WS-1 to calculate baseline water use.
    4. Floor-mounted urinals @ 0.5 GPF or wall-mounted urinals @ 0.125 GPF.|1. The daily use number shall be increased to three if urinals are not installed in the room.
    2. Refer to Table 4-1, Chapter 4, 2025_California Plumbing Code_, for occupant load factors.
    a. Shower use by occupants depends on the type of use of a building or portion of a building, e.g., total occupant load for a health club, but only a fraction of the occupants
    in an office building as determined by the anticipated number of users.
    b. Kitchen faucet use is determined by the occupant load of the area served by the fixture.
    3. Use worksheet WS-1 to calculate baseline water use.
    4. Floor-mounted urinals @ 0.5 GPF or wall-mounted urinals @ 0.125 GPF.|1. The daily use number shall be increased to three if urinals are not installed in the room.
    2. Refer to Table 4-1, Chapter 4, 2025_California Plumbing Code_, for occupant load factors.
    a. Shower use by occupants depends on the type of use of a building or portion of a building, e.g., total occupant load for a health club, but only a fraction of the occupants
    in an office building as determined by the anticipated number of users.
    b. Kitchen faucet use is determined by the occupant load of the area served by the fixture.
    3. Use worksheet WS-1 to calculate baseline water use.
    4. Floor-mounted urinals @ 0.5 GPF or wall-mounted urinals @ 0.125 GPF.|

    A5.303.2.3.1 Tier 1 – 12-percent savings. A schedule of plumbing fixtures and fixture fittings that will reduce the overall use of potable water within the building by 12 percent shall be provided.

  • CALGreen § 0.18 High relevance — show source text

    @ 60 psi]|0.18 gallons/cycle 20 [rim space (in.) @ 60 psi]| |Gravity tank type water closets|1.28 gallons/flush|1.12 gallons/flush1| |Flushometer tank water closets|1.28 gallons/flush|1.12 gallons/flush1| |Flushometer valve water closets|1.28 gallons/flush|1.12 gallons/flush1| |Electromechanical hydraulic water closets|1.28 gallons/flush|1.12 gallons/flush1| |Urinals|0.5 or 0.1254 gallons/flush|0.44 or 0.11 gallons/flush| |1. Includes water closets with an effective flush rate of 1.12 gallons or less when tested per ASME A 112.19.2 and ASME A 112.19.14.
    2. See Table A5.503.2.2 for additional notes and references.
    3. Where complying faucets are unavailable, aerators rated at 0.35 gpm or other means may be used to achieve reduction.
    4. Floor-mounted urinals @ 0.5 GPF or wall-mounted urinals @ 0.125 GPF.|1. Includes water closets with an effective flush rate of 1.12 gallons or less when tested per ASME A 112.19.2 and ASME A 112.19.14.
    2. See Table A5.503.2.2 for additional notes and references.
    3. Where complying faucets are unavailable, aerators rated at 0.35 gpm or other means may be used to achieve reduction.
    4. Floor-mounted urinals @ 0.5 GPF or wall-mounted urinals @ 0.125 GPF.|1. Includes water closets with an effective flush rate of 1.12 gallons or less when tested per ASME A 112.19.2 and ASME A 112.19.14.
    2. See Table A5.503.2.2 for additional notes and references.
    3. Where complying faucets are unavailable, aerators rated at 0.35 gpm or other means may be used to achieve reduction.
    4. Floor-mounted urinals @ 0.5 GPF or wall-mounted urinals @ 0.125 GPF.|

    A5.303.2.3.2 Tier 2 – 20-percent savings. A schedule of plumbing fixtures and fixture fittings that will reduce the overall use of potable water within the building by 20 percent shall be provided. A calculation demonstrating a 20-percent reduction in the building “water use baseline” as established in Table A5.303.2.2 shall be provided. A5.303.2.3.3 25-percent savings. A schedule of plumbing fixtures and fixture fittings that will reduce the overall use of potable water within the building by 25 percent shall be provided. A calculation demonstrating a 25-percent reduction in the building “water use baseline” as established in Table A5.303.2.2 shall be provided. A5.303.2.3.4 Nonpotable water systems for indoor use. Utilizing nonpotable water systems (such as captured rainwater, treated graywater and recycled water) intended to supply water closets, urinals and other allowed uses, may be used in the calculations demonstrating the 12-, 20- or 25-percent reduction. The nonpotable water systems shall comply with the current edition of the California Plumbing Code.

  • CALGreen § 4-1 High relevance — show source text

    Refer to Table 4-1, Chapter 4, 2025_California Plumbing Code_, for occupant load factors.
    a. Shower use by occupants depends on the type of use of a building or portion of a building, e.g., total occupant load for a health club, but only a fraction of the occupants
    in an office building as determined by the anticipated number of users.
    b. Kitchen faucet use is determined by the occupant load of the area served by the fixture.
    3. Use worksheet WS-1 to calculate baseline water use.
    4. Floor-mounted urinals @ 0.5 GPF or wall-mounted urinals @ 0.125 GPF.|1. The daily use number shall be increased to three if urinals are not installed in the room.
    2. Refer to Table 4-1, Chapter 4, 2025_California Plumbing Code_, for occupant load factors.
    a. Shower use by occupants depends on the type of use of a building or portion of a building, e.g., total occupant load for a health club, but only a fraction of the occupants
    in an office building as determined by the anticipated number of users.
    b. Kitchen faucet use is determined by the occupant load of the area served by the fixture.
    3. Use worksheet WS-1 to calculate baseline water use.
    4. Floor-mounted urinals @ 0.5 GPF or wall-mounted urinals @ 0.125 GPF.|

    A5.303.2.3.1 Tier 1 – 12-percent savings. A schedule of plumbing fixtures and fixture fittings that will reduce the overall use of potable water within the building by 12 percent shall be provided. The reduction shall be based on the maximum allowable water use per plumbing fixture and fitting as required by the California Building Standards Code. The 12-percent reduction in potable water use shall be demonstrated by one of the following methods:

    1. Prescriptive method. Each plumbing fixture and fitting shall not exceed the maximum flow rate at greater than or equal to 12-percent reduction as specified in Table A5.303.2.3.1; or
    2. Performance method. A calculation demonstrating a 12-percent reduction in the building “water use baseline” as established in Table A5.303.2.2 shall be provided.

    2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A5-19

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

    APPENDIX A5 — NONRESIDENTIAL VOLUNTARY MEASURES

    TABLE A5.303.2.3.1—FIXTURE FLOW RATES (PRESCRIPTIVE METHOD) Col2 Col3
    FIXTURE TYPE BASELINE FLOW RATE2 MAXIMUM FLOW RATE AT≥** 12 PERCENT**
    REDUCTION
    Showerheads 1.8 gpm @ 80 psi 1.6 gpm @ 80 psi
    Lavatory faucets nonresidential3 0.5 gpm @ 60 psi 0.35 gpm @ 60 psi
    Kitchen faucets3 1.8 gpm @ 60 psi 1.6 gpm @ 60 psi
    Wash fountains 1.8 gallons/cycle/20 [rim space (in.) @ 60 psi] 1.6 gpm/20 [rim space (in.)
  • CALGreen § 601.2.4 High relevance — show source text

    A5.601.2.4 Voluntary measures for Tier 1. In addition to the provisions of Sections A5.601.2.1 and A5.601.2.3 above, compliance with the following voluntary measures from Appendix A5 is required for Tier 1:

    1. From Division A5.1, a. Comply with the designated parking requirements for high-efficiency vehicles for a minimum of 35 percent of parking capacity per Section A5.106.5.1. b. Electric vehicle (EV) charging [N] and Table A5.106.5.3.1 w/ footnotes. c. Comply with thermal emittance, solar reflectance or SRI values for cool roofs in Section A5.106.11.2 and Table A5.106.11.2.2. [1]

    d. Comply with one elective measure selected from this division. 2. From Division A5.2 comply with ONE of the following:

    1. Outdoor lighting as described in A5.203.1.1.1.

    2. Service water heating in restaurants as described in A5.203.1.1.2.

    3. Warehouse Dock Seal Doors A5.203.1.1.3.

    4. Daylight Design Power Adjustments 5.203.1.1.4.

    5. Exhaust Air Heat Recovery A5.203.1.1.5.

    6. From Division A5.3,

    a. Comply with the 12-percent reduction for indoor potable water use in Section A5.303.2.3.1. b. Comply with one elective measure selected from this division.

    1. From Division A5.4,

    a. Comply with recycled content of 10 percent of materials based on estimated total cost, or use two products from Table A5.405.4 for at least 75 percent by cost in Section A5.405.4. b. Comply with the 65-percent reduction in construction and demolition waste in Section A5.408.3.1. c. Comply with one elective measure selected from this division.

    1. From Division A5.5,

    a. Comply with resilient flooring systems for 90 percent of resilient flooring in Section A5.504.4.7. b. Comply with thermal insulation meeting 2009 CHPS low-emitting materials list in Section A5.504.4.8. c. Comply with one elective measure selected from this division. 6. Comply with one additional elective measure selected from any division.

    1 Cool roof is required for compliance with Tiers 1 and 2 and may be used to meet energy standards in Part 6, exceed energy standards and to mitigate heat island effect.

    A5.601.3 CALGreen Tier 2.

    A5.601.3.1 Prerequisites. To achieve CALGreen tier status, a project must meet all of the mandatory measures in Chapter 5 and, in addition, meet the provisions of this section.

    A5.601.3.2 Energy performance. For the purposes of mandatory energy efficiency standards in this code, the California Energy Commission will continue to adopt mandatory standards.

    A5.601.3.3 Tier 2. Comply with the energy efficiency requirements in Section A5.203.1.1 and Section A5.203.1.2.2.

  • CALGreen § 409.4 High relevance — show source text

    Solar access is the ratio of solar insolation including shade to the
    solar insolation without shade. Shading from obstructions located on the roof or any other part of the building shall not be included in the determination of annual solar access.
    3.
    Life cycle assessment compliant with Section A5.409.4 in this code may be substituted for prescriptive measures from Division A5.4.|

    A5.601.1 Scope. The measures contained in this appendix are not mandatory unless adopted by local government as specified in Section 101.7. The provisions of this section outline means of achieving enhanced construction or reach levels by incorporating addi

    2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A5-41

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

    APPENDIX A5 — NONRESIDENTIAL VOLUNTARY MEASURES

    tional green building measures for newly constructed nonresidential buildings as well as additions and alterations. In order to meet one of the tier levels designers, builders or property owners are required to incorporate additional green building measures necessary to meet the threshold of each level. Refer to the provisions in Section 301.3 for nonresidential additions and alterations scope and application.

    A5.601.2 CALGreen Tier 1

    A5.601.2.1 Prerequisites. To achieve CALGreen tier status, a project must meet all of the mandatory measures in Chapter 5 and, in addition, meet the provisions of this section.

    A5.601.2.2 Energy performance. For the purposes of mandatory energy efficiency standards in this code, the California Energy Commission will continue to adopt mandatory standards.

    A5.601.2.3 Tier 1. Comply with the energy efficiency requirements in Section A5.203.1.1 and Section A5.203.1.2.1.

    A5.601.2.4 Voluntary measures for Tier 1. In addition to the provisions of Sections A5.601.2.1 and A5.601.2.3 above, compliance with the following voluntary measures from Appendix A5 is required for Tier 1:

    1. From Division A5.1, a. Comply with the designated parking requirements for high-efficiency vehicles for a minimum of 35 percent of parking capacity per Section A5.106.5.1. b. Electric vehicle (EV) charging [N] and Table A5.106.5.3.1 w/ footnotes. c. Comply with thermal emittance, solar reflectance or SRI values for cool roofs in Section A5.106.11.2 and Table A5.106.11.2.2. [1]

    d. Comply with one elective measure selected from this division. 2. From Division A5.2 comply with ONE of the following:

    1. Outdoor lighting as described in A5.203.1.1.1.

    2. Service water heating in restaurants as described in A5.203.1.1.2.

    3. Warehouse Dock Seal Doors A5.203.1.1.3.

    4. Daylight Design Power Adjustments 5.203.1.1.4.

    5. Exhaust Air Heat Recovery A5.203.1.1.5.

    6. From Division A5.3,

    a. Comply with the 12-percent reduction for indoor potable water use in Section A5.303.2.3.1. b. Comply with one elective measure selected from this division.

    1. From Division A5.4,
  • 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 § 303.1 High relevance — show source text

    2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A4-11

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

    APPENDIX A4-12 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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

    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 § 4.303.1 Medium relevance — show source text

    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
    WATER EFFICIENCY AND CONSERVATION
    Indoor Water Use
    4.303.1Plumbing fixtures (water closets and urinals) and fittings
    (showerheads, faucets and pre-rinse spray valves) installed in
    residential buildings shall comply with the prescriptive requirements
    of Sections 4.303.1.1 through 4.303.1.4.5.
    4.303.2 Submeters for multifamily building and dwelling units in
    mixed-use residential/commercial buildings. Submeters shall be
    installed to measure water usage of individual rental dwelling units in
    accordance with the_California Plumbing Code._
    4.303.3Plumbing fixtures and fittings required in Section 4.303.1
    shall be installed in accordance with the_California Plumbing Code,_
    and shall meet the applicable referenced standards.
    A4.303.1The 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.
    4.303.1.4.3 Metering faucets in residential buildings shall not deliver
    more than 0.2 gallons per cycle.
    A4.303.2Alternate water source 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.
  • CALGreen § 4.303.3 Medium relevance — show source text

    ** Submeters shall be
    installed to measure water usage of individual rental dwelling units in
    accordance with the_California Plumbing Code.||||||| |4.303.3Plumbing fixtures and fittings required in Section 4.303.1
    shall be installed in accordance with the_California Plumbing Code,
    and shall meet the applicable referenced standards.||||||| |A4.303.1The 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.||||||| |4.303.1.4.3 Metering faucets in residential buildings shall not deliver
    more than 0.2 gallons per cycle.||||||| |A4.303.2Alternate water source 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 Install at least one qualified ENERGY STAR dishwasher or
    clothes washer.||
    |
    |
    |
    |
    | |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.

  • CALGreen § 303.3.4.6 Medium relevance — show source text

    303.3.4.6||||| |DIVISION 5.3
    Water
    Efficiency and
    Conservation|DIVISION 5.3
    Water
    Efficiency and
    Conservation|Mandatory|Food waste disposers|5.303.4.1||||| |DIVISION 5.3
    Water
    Efficiency and
    Conservation|DIVISION 5.3
    Water
    Efficiency and
    Conservation|Mandatory|Areas of additions or alterations|5.303.5||||| |DIVISION 5.3
    Water
    Efficiency and
    Conservation|DIVISION 5.3
    Water
    Efficiency and
    Conservation|Mandatory|Standards for plumbing fixtures and fittings|5.303.6||||| |DIVISION 5.3
    Water
    Efficiency and
    Conservation|DIVISION 5.3
    Water
    Efficiency and
    Conservation|Mandatory|Outdoor potable water use in landscape areas (with notes)|5.304.1||||| ||Select One Elective|Elective|Nonpotable water systems for indoor use|A5.303.2.3.4||||| ||Select One Elective|Elective|Appliances and fixtures for commercial application|A5.303.3||||| ||Select One Elective|Elective|Nonwater urinals|A5.303.4.1||||| ||Select One Elective|Elective|Dual plumbing|A5.303.5||||| ||Select One Elective|Elective|Outdoor potable water use|A5.304.2||||| ||Select One Elective|Elective|Restoration of areas disturbed by construction|A5.304.6||||| ||Select One Elective|Elective|Previously developed sites (with exception)|A5.304.7||||| ||Select One Elective|Elective|Graywater irrigation system|A5.304.8||||| ||Select One Elective|Elective|Nonpotable water systems|A5.305.1||||| ||Select One Elective|Elective|Irrigation systems|A5.305.2||||| |DIVISION 5.4
    Material
    Conservation
    and Resource
    Efficiency
    (continued)|DIVISION 5.4
    Material
    Conservation
    and Resource
    Efficiency
    (continued)|Tier 1
    Prerequisite|Recycled content for 10% of total material cost|A5.405.4,
    A5.405.4.1
    through
    A5.405.4.5||||| |**DIVISION 5.

  • CALGreen § 8.5 Medium relevance — show source text

    The white-shaded cells accept input from the designer. For instance, fixture counts from the given information are entered in Column [B]; the corresponding recommended fixture flow rates are already provided in Column [D]. The flow rates in Column [D] may be reduced only if the manufacturer specifies a lower flow rate for the fixture. Column [E] establishes the upper limits for the flow rates entered into Column

    [D]. Clicking the Run Water Demand Calculator button gives 8.5 gpm (0.54 L/s) as the estimated indoor water demand for the whole building. This result appears in the dark gray box FIGURE 1 of the WDC in Figure 2. RESIDENTIAL BUILDING WITH SIX INDOOR FIXTURES

    520 2025 CALIFORNIA PLUMBING CODE

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

    APPENDIX M

    [A]
    FIXTURE    		 Col2 [B]
    ENTER NUMBER OF
    FIXTURES    		 [C]
    PROBABILITY
    OF USE (%)    		 [D]
    ENTER FIXTURE
    FLOW RATE (GPM)    		 [E]
    MAXIMUM RECOMMENDED FIX-
    TURE FLOW RATE (GPM)
    1 Bar Sink 0 2.0 1.5 1.5
    2 Bathtub 0 1.0 5.5 5.5
    3 Bidet 0 1.0 2.0 2.0
    4 Clothes Washer 1 5.5 3.5 3.5
    5 Combination Bath/Shower 1 5.5 5.5 5.5
    6 Dishwasher 1 0.5 1.3 1.3
    7 Kitchen Faucet 1 2.0 2.2 2.2
    8 Laundry Faucet 0 2.0 2.0 2.0
    9 Lavatory Faucet 1 2.0 1.5 1.5
    10 Shower, per head 0 4.5 2.0 2.0
    11 Water Closet, 1.28 GPF Gravity Tank 1 1.0 3.0 3.0
    12 Other Fixture 1 0 0.0 0.0 6.0
    13 Other Fixture 2 0 0.0 0.0 6.0
    14 Other Fixture 3 0 0.0 0.0 6.0
    Total Number of Fixtures Total Number of Fixtures 6 RESET RUN WATER DEMAND
    CALCULATOR
    99th Percentile Demand Flow = 99th Percentile Demand Flow = 8.5 GPM

    For SI units: 1 gallon per minute = 0.66 L/s, 1 gallon = 3.785 L

    FIGURE 2 WATER DEMAND CALCULATOR FOR INDOOR USE AT HOME WITH SIX EFFICIENT FIXTURES (EXAMPLE 1)

    Solution: Step 2 of 2 – Determine the Pipe Size of the Building Supply.

Frequently asked questions

What if I can’t find fixtures rated as low as the table requires?

If complying fixtures are unavailable, consult the table footnotes—the appendix allows alternatives such as aerators rated at 0.35 gpm or other means to achieve the reduction, or use the performance method to show an overall 12% reduction. Always document availability and the chosen compliance path per § 5.303.2.3.1 .

Can nonpotable water (rainwater/graywater) be counted toward the 12%?

Yes. Appendix section A5.303.2.3.4 allows nonpotable sources to be used in the reduction calculation, provided the nonpotable system complies with the California Plumbing Code and is properly documented in the performance calculation .

Do I have to use the prescriptive table for every fixture?

No — you may choose the performance method and show a whole‑building 12% reduction from the baseline (Worksheet WS‑1). The prescriptive table is an alternative route that simplifies compliance if all fixtures meet the listed maximums (§ 5.303.2.3.1) .

Where do I find the baseline inputs for the performance calculation?

Use Worksheet WS‑1 and Table A5.303.2.2 (Chapter 8 references) for the baseline flow rates, durations, daily uses, and occupant factors required to compute the building baseline; these are the official inputs for the performance method .

Is the Appendix A5 mandatory statewide?

Appendix A5 is voluntary unless adopted locally. The Tier 1 12% measure is part of Appendix A5 (voluntary tiers) and applies when a local jurisdiction or project elects Tier 1 compliance per the code’s voluntary tier provisions .

More in California Green Building Standards Code (CALGreen)

Ask about the CALGreen

Get cited, plain-English answers on the California Green Building Standards Code (CALGreen) for your project — any code section, any scenario.

Start Free Trial

Related in the CALGreen

Landscape irrigation requirements and MWELO references for nonresidential sites

Basis-of-design and commissioning requirements for landscape irrigation and water reuse systems

Water Efficiency & Conservation (Division 5.3)

California Green Building Standards Code (CALGreen)