CALGreen · California Green Building Standards Code (CALGreen)

How is baseline water use calculated and where are the worksheets?

CALGreen’s official baseline method uses Worksheet WS‑1 (Chapter 8): for each fixture, multiply the worksheet’s baseline flow rate × duration × daily uses × occupant count, sum all fixtures to get the building BWU, then use WS‑2 to apply the required percent reductions (12%, 20% or 25%). Use occupant loads from the California Plumbing Code Table 4‑1 and follow worksheet notes for urinals, nonwater fixtures and substitutions.

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Last reviewed: July 6, 2026

What the code requires — plain English

The building’s baseline water use (BWU) is calculated by adding up the water use for each plumbing fixture using the Worksheet (WS-1) — Baseline Water Use in Chapter 8. The worksheet supplies the baseline flow rates, typical durations and daily uses to compute gallons per day per fixture; those per-fixture numbers are summed to produce the building BWU. See the Worksheet (WS-1) Baseline Water Use (Chapter 8) and the Water Use Baseline Table referenced in the CALGreen appendices for the baseline values.

Use Worksheet WS-1 (Chapter 8) to compute the building baseline water use (BWU) by fixture: gallons/day = flow rate × duration × daily uses × occupants; sum all fixtures to get BWU.

Requirements in detail

The method (formula)

  • For each fixture type, BWU contribution = flow rate × duration × daily uses × occupants. The WS-1 table lists the baseline flow rate, the duration and the daily uses to use in the calculation; the designer supplies the occupant count (see exceptions below).

Where the worksheet is and when to use it

  • The Worksheet (WS-1) — Baseline Water Use is provided in Chapter 8 as the official baseline-calculation form; the code explicitly directs use of WS-1 to calculate baseline water use.
  • When demonstrating the required percentage reductions (12%, 20% or 25%), the BWU computed on WS-1 is the starting value used in Worksheet (WS-2) to show allowable water use after the required reduction (e.g., BWU × 0.88 for 12% reduction).

Decision‑relevant dimensions (quick reference)

Decision dimension Typical worksheet value (baseline) Units / notes Code Reference
Showerheads baseline flow 1.8 gpm @ 80 psi Duration = 5 min; daily uses = 1 Worksheet (WS-1), Chapter 8; Water Use Baseline Table § A5.303.2.2
Lavatory faucets (nonresidential) baseline flow 0.5 gpm @ 60 psi Duration = 0.25 min; daily uses = 3 WS-1 (Chapter 8), § A5.303.2.2
Kitchen faucets baseline flow 1.8 gpm @ 60 psi Duration = 4 min; daily uses = 1 WS-1, § A5.303.2.2
Water closets (toilets) baseline flow 1.28 gal/flush Duration = 1 flush WS-1, § A5.303.2.2
Urinals baseline flow 0.5 or 0.125 gal/flush Duration = 1 flush; WS notes alternative urinal flows WS-1, § A5.303.2.2
Percent reduction math 12% → BWU × 0.88; 20% → BWU × 0.80; 25% → BWU × 0.75 Use WS-2 for showing proposed vs allowable use Worksheet (WS-2), Chapter 8; § A5.303.2.3.1 (tiers)

(Each baseline input above and the WS-1 worksheet form itself are provided in Chapter 8’s WS-1 Baseline Water Use sample form.)

What to enter on WS-1

  • Enter the fixture type, use the baseline flow rate shown on WS-1, fill in duration and daily uses from WS-1, and enter the applicable occupant count for the area served. Multiply across to produce gallons per day per fixture type, then sum to get Total daily baseline water use (BWU).

Exceptions & special cases

  • Occupant counts: For nonresidential occupancies the worksheet instructs users to obtain occupant load factors from Table 4‑1, Chapter 4 of the California Plumbing Code (CPC). WS-1 does not supply CPC occupant loads — you must use CPC Table 4‑1. If that table determines the occupant number, use it on WS-1.
  • Urinals and no‑urinal adjustment: WS-1 notes increase the daily use number to three if urinals are not installed in a room (i.e., adjust the daily uses per the worksheet note). Also, WS-2 allows nonwater urinals to be entered as 0.0 gal/flush where appropriate when calculating proposed use.
  • Replacement aerators / unavailable fixtures: The code notes alternatives (e.g., aerators) where complying faucets are unavailable — see WS notes and Appendix sections for allowable substitutions. Always document on WS-1/WS-2 when relying on alternative fittings.
  • Voluntary tiers and prescriptive paths: Appendix provisions (e.g., § A5.303.2.3.1) describe Tier 1 (12%), Tier 2 (20%), or 25% voluntary savings and allow either prescriptive fixture schedules or the performance method using BWU from WS-1.

Common mistakes

  • Using the actual fixture flow (manufacturer label) for baseline instead of the baseline flow rates in WS-1 — WS-1 provides the regulatory baseline values to start from. Always use WS-1 baseline values for calculating BWU.
  • Forgetting to derive occupant counts from the CPC (Table 4‑1) for nonresidential buildings and instead guessing or using residential assumptions. WS-1 points users to CPC Table 4‑1 for occupant factors.
  • Not adjusting daily uses per worksheet notes (for example, not increasing daily uses when urinals are omitted). Check WS-1 notes carefully.
  • Mixing prescriptive fixture flow requirements (Appendix tables) with the performance calculation incorrectly — if using performance, you must show the BWU (WS-1) and then the proposed reduced use (WS-2).

Worked example — small office (illustrative)

Assumptions (for illustration only):

  • Building: small office; assumed occupant count = 10 (for a real project, use CPC Table 4‑1 to determine occupant counts). WS-1 method and baseline values are used.

Step 1 — per‑fixture baseline contributions (use WS-1 numbers)

  • Lavatory faucets: baseline flow 0.5 gpm, duration 0.25 min, daily uses 3.
    • Per occupant: 0.5 × 0.25 × 3 = 0.375 gallons/day.
    • For 10 occupants: 0.375 × 10 = 3.75 gallons/day.
  • Kitchen faucet (common break area): baseline flow 1.8 gpm, duration 4 min, daily uses 1.
    • Per occupant: 1.8 × 4 × 1 = 7.2 gallons/day.
    • For 10 occupants: 7.2 × 10 = 72.0 gallons/day.
  • Water closets: baseline 1.28 gal/flush, duration 1 flush (WS-1 baseline).
    • If using 1 flush/day per occupant (example assumption): 1.28 × 1 × 10 = 12.8 gallons/day.

Step 2 — sum to get BWU

  • BWU = 3.75 + 72.0 + 12.8 = 88.55 gallons/day (baseline total, from WS-1 inputs).

Step 3 — show a 20% reduction (performance path) using WS-2

  • Allowable water use = BWU × 0.80 = 88.55 × 0.80 = 70.84 gallons/day.
  • On Worksheet (WS-2) you would enter the proposed fixture flows and show the proposed total is ≤ 70.84 gpd to demonstrate compliance with a 20% reduction.

Notes:

  • This example assumes occupant and “uses per day” values for illustration; for compliance you must use occupant counts per the CPC and complete WS-1 and WS-2 forms exactly as provided in Chapter 8.

Related provisions (CALGreen)

  • § A5.303.2.2 — Water Use Baseline Table (references baseline values used by WS-1).
  • § A5.303.2.3.1 — Tier 1 (12%) (performance or prescriptive paths referencing baseline).
  • Worksheet WS-1, Chapter 8 — Baseline Water Use (the actual worksheet/form you must complete).
  • Worksheet WS-2, Chapter 8 — 12%, 20% or 25% Reduction Water Use Calculation Table (applies BWU to allowable use).
  • § A5.303.4 — Nonwater urinals and water-conserving plumbing fixtures provisions (related fixture rules).
  • § 5.303 (Indoor water use provisions) and § 4.303.1 (fixture flow rate tables referenced elsewhere in the code) — other CALGreen sections tied to indoor water use.

(If you need the official WS‑1 PDF or sample form to file with your permit, see Chapter 8 — compliance worksheets; HCD provides sample CALGreen forms online as well.)

Code references

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

  • CALGreen § 8-3 High relevance — show source text

    CHAPTER 8 COMPLIANCE FORMS, WORKSHEETS AND

    REFERENCE MATERIAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3

    Worksheet (WS-1) Baseline Water Use: Baseline Water Use Calculation Table . . . . . . . . . . .8-3

    Worksheet (WS-2) Water Use Reduction: 12-, 20- or 25-Percent Reduction Water Use Calculation Table . . . . . . . . . . . . . . . . . . .8-4

    Worksheet (WS-3) 5.105.2 Building Reuse . . . . . . . . . . . . . . . .8-4 Worksheet (WS-4) 5.409.2 Whole Building Life Cycle Assessment:. . . . . . . . . . . . . . . . . . . . . . . . .8-5 Worksheet (WS-5) 5.409.3 Product GWP Compliance—Prescriptive Path: . . . . . . . . . . . . . . . .8-5

    Worksheet (WS-6) A5.105.2 Building Reuse Tier 1 and Tier 2:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5

    Worksheet (WS-7) A5.409.2 Whole Building Life Cycle Assessment: . . . . . . . . . . . . . . . . . . . . . . . . 8-6 Worksheet (WS-8) A5.409.3 Product GWP Compliance—Prescriptive Path:. . . . . . . . . . . . . . . . 8-6 Worksheet (WS-9) 5.409.2 and A5.409.2 Whole Building Life Cycle Assessment: . . . . . . . . . . . . . . . . 8-7 Construction Waste Management (CWM) Plan . . . . . . . . . . . 8-8 Construction Waste Management (CWM) Worksheet. . . . . . 8-9 Construction Waste Management (CWM) Acknowledgment. . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10 Title 23, Waters, California Code of Regulations . . . . . . . . . 8-11 Commissioning Referenced Standards for Non-energy Systems. . . . . . . . . . . . . . . . . . . . . . . . . 8-13 IES TM-15-11 Table A-1, Table 130.2-A and Table 130.2-B Uplight and Glare Ratings Tables. . . . . . . . . . . . . . 8-40

  • CALGreen § 0.20 High relevance — show source text

    @ 60 psi]|||X| |Metering faucets|0.20 gallons/cycle|.25 min.|3|X| |Metering faucets for wash fountains|0.20 gallons/cycle/20 [rim space (in.) @ 60 psi]|.25 min.|1 male1
    3 female|X| |Gravity tank type water closets|1.28 gallons/flush|1 flush|1 male1
    3 female|X| |Flushometer tank water closets|1.28 gallons/flush|1 flush|1 male1
    3 female|X| |Flushometer valve water closets|1.28 gallons/flush|1 flush|1 male1
    3 female|X| |Electromechanical hydraulic water
    closets|1.28 gallons/flush|1 flush|1 male1
    3 female|X| |Urinals|0.5 or 0.1254 gallons/flush|1 flush|2 male|X| |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.|1. The daily use number shall be increased to three if urinals are not installed in the room.
    2.

  • CALGreen § 5.1 High relevance — show source text

    5.1 Planning and Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-3 5.2 Energy Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-15 5.3 Water Efficiency and Conservation . . . . . . . . . . . . . . . 5-19 5.4 Material Conservation and Resource Efficiency . . . . 5-23 5.5 Environmental Quality . . . . . . . . . . . . . . . . . . . . . . . . . . 5-31

    CHAPTER 6 REFERENCED ORGANIZATIONS

    AND STANDARDS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3

    601 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-3

    CHAPTER 7 INSTALLER AND SPECIAL

    INSPECTOR QUALIFICATIONS . . . . . . . . . . . . . . . . . . . . . . 7-3 701 General (Reserved) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-3 702 Qualifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-3

    703 Verifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-3

    CHAPTER 8 COMPLIANCE FORMS, WORKSHEETS AND

    REFERENCE MATERIAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3

    Worksheet (WS-1) Baseline Water Use: Baseline Water Use Calculation Table . . . . . . . . . . .8-3

    Worksheet (WS-2) Water Use Reduction: 12-, 20- or 25-Percent Reduction Water Use Calculation Table . . . . . . . . . . . . . . . . . . .8-4

    Worksheet (WS-3) 5.105.2 Building Reuse . . . . . . . . . . . . . . . .8-4 Worksheet (WS-4) 5.409.2 Whole Building Life Cycle Assessment:. . . . . . . . . . . . . . . . . . . . . . . . .8-5 Worksheet (WS-5) 5.409.3 Product GWP Compliance—Prescriptive Path: . . . . . . . . . . . . . . . .8-5

    Worksheet (WS-6) A5.105.2 Building Reuse Tier 1 and Tier 2:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5

    Worksheet (WS-7) A5.409.2 Whole Building Life Cycle Assessment: . . . . . . . . . . . . . .

  • 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 § 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 § 303.2.3.3 High relevance — show source text

    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, Chapter 8, (WS-8) Whole Building Life Cycle Assessment 5.409.2, A5.409.2, Chapter 8, (WS-9)

    INDEX-2 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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

    HISTORY NOTE APPENDIX

    2025 California Green Building Standards Code California Code of Regulations, Title 24, Part 11

    HISTORY:

    For prior history, see the History Note Appendix to the California Green Building Standards Code, 2022 Edition, effective January 1, 2023.

    1. (BSC 03/24, HCD 04/24, DSA-SS 03/24, CEC 02/24)—Repeal the 2022 adoption of the California Green Building Standards Code, CCR Title 24, Part 11 and adopt the 2025 California Green Building Standards Code . Approved by the California Building Standards Commission on December 17, 2024, filed with the Secretary of State on January 10, 2025, and effective on January 1, 2026.

    2025 CALIFORNIA GREEN BUILDING STANDARDS CODE HIST-1

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

  • CALGreen § 1.8 High relevance — show source text

    [HCD 1] Sample forms located at www.hcd.ca.gov/building-standards/calgreen/cal-green-forms.shtml may be used to assist in documenting compliance with CALGreen . WORKSHEET (WS-1) BASELINE WATER USE

    BASELINE WATER USE CALCULATION TABLE Col2 Col3 Col4 Col5 Col6 Col7 Col8 Col9 Col10
    FIXTURE TYPE FLOW RATE DURATION DAILY USES OCCUPANTS1 GALLONS PER DAY
    Showerheads 1.8 gpm @ 80 psi × 5 min. × 1 × Note 1a =
    Lavatory faucets nonresidential 0.5 gpm @ 60 psi × .25 min. × 3 × =
    Kitchen faucets 1.8 gpm @ 60 psi × 4 min. × 1 × Note 1b =
    Replacement aerators 2.2 gpm × × × =
    Wash fountains 1.8 gpm/20 [rim
    space(in.)@ 60 psi]    		 × × × =
    Metering faucets 0.20 gal/cycle × × 3 × =
    Metering faucets for wash
    fountains    		 0.20 gal/cycle/20 [rim
    space(in.)@ 60 psi]    		 × .25 min. × × =
    Gravity tank-type water closets 1.28 gal/flush × 1 flush × 1 male2
    3 female    		 × =
    Flushometer tank water closets 1.28 gal/flush × 1 flush × 1 male2
    3 female    		 × =
    Flushometer valve water closets 1.28 gal/flush × 1 flush × 1 male2
    3 female    		 × =
    Electromechanical hydraulic
    water closets    		 1.28 gal/flush × 1 flush × 1 male2
    3 female    		 × =
    Urinals 0.5 or 0.1253 gal/flush × 1 flush × 2 male × =
    Total daily baseline water use (BWU) Total daily baseline water use (BWU) Total daily baseline water use (BWU) Total daily baseline water use (BWU) Total daily baseline water use (BWU) Total daily baseline water use (BWU) Total daily baseline water use (BWU) Total daily baseline water use (BWU) =
    1. For nonresidential occupancies, 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.
    2. The daily use number shall be increased to three if urinals are not installed in the room.
    3. Floor-mounted urinals @ 0.5 GPF or wall-mounted urinals @ 0.125 GPF.    		 1.
  • 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 § 15-11 High relevance — show source text

    are listed below||||||||X||||||||||||||| |Chapter/Section||||||||||||||||||||||| |WS-3||||||||X||||||||||||||| |WS-4||||||||X||||||||||||||| |WS-5||||||||X||||||||||||||| |WS-9||||||||X||||||||||||||| |IES TM-15-11 Table A-1||||||||X||||||||||||||| |Table 130.2-A||||||||X||||||||||||||| |Table 1302.2-B||||||||X|||||||||||||||

    2025 CALIFORNIA GREEN BUILDING STANDARDS CODE 8-1

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

    8-2 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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

    8 COMPLIANCE FORMS, WORKSHEETS AND REFERENCE MATERIAL

    [BSC] Sample forms found in “A Guide to the California Green Building Standards Code (Nonresidential)” located at https://www.dgs.ca.gov/BSC/Resources/Page-Content/Building-Standards-Commission-Resources-List-Folder/CALGreen may be used to assist in documenting compliance with the waste management plan and other provisions of this code.

    [HCD 1] Sample forms located at www.hcd.ca.gov/building-standards/calgreen/cal-green-forms.shtml may be used to assist in documenting compliance with CALGreen . WORKSHEET (WS-1) BASELINE WATER USE

    BASELINE WATER USE CALCULATION TABLE Col2 Col3 Col4 Col5 Col6 Col7 Col8 Col9 Col10
    FIXTURE TYPE FLOW RATE DURATION DAILY USES OCCUPANTS1 GALLONS PER DAY
    Showerheads 1.8 gpm @ 80 psi × 5 min. × 1 × Note 1a =
    Lavatory faucets nonresidential 0.5 gpm @ 60 psi × .25 min. × 3 × =
    Kitchen faucets 1.8 gpm @ 60 psi × 4 min. × 1 × Note 1b =
    Replacement aerators 2.2 gpm × × × =
    Wash fountains 1.8 gpm/20 [rim
    space(in.)@ 60 psi]    		 × × × =
    Metering faucets 0.20 gal/cycle × × 3 × =
    Metering faucets for wash
    fountains    		 0.20 gal/cycle/20 [rim
    space(in.
  • CALGreen § 0.5 High relevance — show source text

    Kitchen faucet use is determined by the occupant load of the area served by the fixture.
    2. The daily use number shall be increased to three if urinals are not installed in the room.
    3. Floor-mounted urinals @ 0.5 GPF or wall-mounted urinals @ 0.125 GPF.|

    2025 CALIFORNIA GREEN BUILDING STANDARDS CODE 8-3

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

    COMPLIANCE FORMS, WORKSHEETS AND REFERENCE MATERIAL

    WORKSHEET (WS-2) WATER USE REDUCTION

    12-, 20- OR 25-PERCENT REDUCTION WATER USE CALCULATION TABLE Col2 Col3 Col4 Col5 Col6 Col7 Col8 Col9 Col10
    FIXTURE TYPE FLOW RATE2 DURATION DAILY USES OCCUPANTS1 GALLONS PER DAY
    Showerheads × 5 min. × 1 × Note 1a =
    Lavatory faucets nonresidential4 × .25 min. × 3 × =
    Kitchen faucets × 4 min. × 1 × Note 1b =
    Replacement aerators × × × =
    Wash fountains × × × =
    Metering faucets × .25 min. × 3 × =
    Metering faucets for wash fountains × .25 min. × × =
    Gravity tank-type water closets × 1 flush × 1 male3
    3 female    		 × =
    Flushometer tank water closets × 1 flush × 1 male3
    3 female    		 × =
    Flushometer valve water closets × 1 flush × 1 male3
    3 female    		 × =
    Electromechanical hydraulic water
    closets    		 × 1 flush × 1 male3
    3 female    		 × =
    Urinals × 1 flush × 2 male × =
    Urinals
    Nonwater supplied    		 0.0 gal/flush 1 flush 2 male ×
    Proposed water use Proposed water use Proposed water use Proposed water use Proposed water use Proposed water use Proposed water use Proposed water use =
    12% Reduction___________ (BWU from WS-1)× .88 = __________ Allowable water use
    20% Reduction___________ (BWU from WS-1)× .80 = __________ Allowable water use
    25% Reduction___________ (BWU from WS-1)× .75 = __________ Allowable water use    		 12% Reduction___________ (BWU from WS-1)× .88 = __________ Allowable water use
    20% Reduction___________ (BWU from WS-1)× .80 = __________ Allowable water use
    25% Reduction___________ (BWU from WS-1)× .75 = __________ Allowable water use    		 12% Reduction___________ (BWU from WS-1)× .88 = __________ Allowable water use
    20% Reduction___________ (BWU from WS-1)× .
  • CALGreen § 4-1 Medium relevance — show source text

    80 = __________ Allowable water use
    25% Reduction___________ (BWU from WS-1)× .75 = __________ Allowable water use|12% Reduction___________ (BWU from WS-1)× .88 = __________ Allowable water use
    20% Reduction___________ (BWU from WS-1)× .80 = __________ Allowable water use
    25% Reduction___________ (BWU from WS-1)× .75 = __________ Allowable water use|12% Reduction___________ (BWU from WS-1)× .88 = __________ Allowable water use
    20% Reduction___________ (BWU from WS-1)× .80 = __________ Allowable water use
    25% Reduction___________ (BWU from WS-1)× .75 = __________ Allowable water use|12% Reduction___________ (BWU from WS-1)× .88 = __________ Allowable water use
    20% Reduction___________ (BWU from WS-1)× .80 = __________ Allowable water use
    25% Reduction___________ (BWU from WS-1)× .75 = __________ Allowable water use|12% Reduction___________ (BWU from WS-1)× .88 = __________ Allowable water use
    20% Reduction___________ (BWU from WS-1)× .80 = __________ Allowable water use
    25% Reduction___________ (BWU from WS-1)× .75 = __________ Allowable water use|12% Reduction___________ (BWU from WS-1)× .88 = __________ Allowable water use
    20% Reduction___________ (BWU from WS-1)× .80 = __________ Allowable water use
    25% Reduction___________ (BWU from WS-1)× .75 = __________ Allowable water use|12% Reduction___________ (BWU from WS-1)× .88 = __________ Allowable water use
    20% Reduction___________ (BWU from WS-1)× .80 = __________ Allowable water use
    25% Reduction___________ (BWU from WS-1)× .75 = __________ Allowable water use|12% Reduction___________ (BWU from WS-1)× .88 = __________ Allowable water use
    20% Reduction___________ (BWU from WS-1)× .80 = __________ Allowable water use
    25% Reduction___________ (BWU from WS-1)× .75 = __________ Allowable water use| |1. For occupancies, 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.
    2. Includes single and dual flush water closets with an effective flush of 1.28 gallons or less.
    Single flush toilets - The effective flush volume shall not exceed 1.28 gallons (4.8 liters). The effective flush volume is the average flush volume when tested in accordance
    with ASME A112.19.2.
    Dual flush toilets - The effective flush volume shall not exceed 1.28 gallons (4.8 liters). The effective flush volume is defined as the composite, average flush volume of two
    reduced flushes and one full flush.

  • CALGreen § 7-4 Medium relevance — show source text

    7-4 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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

    CALIFORNIA GREEN BUILDING STANDARDS CODE – MATRIX ADOPTION TABLE

    CHAPTER 8 – COMPLIANCE FORMS, WORKSHEETS AND REFERENCE MATERIAL

    (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    		 X
    Chapter/Section
    WS-3 X
    WS-4 X
    WS-5 X
    WS-9 X
    IES TM-15-11 Table A-1 X
    Table 130.2-A X
    Table 1302.2-B X

    2025 CALIFORNIA GREEN BUILDING STANDARDS CODE 8-1

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

    8-2 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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

    8 COMPLIANCE FORMS, WORKSHEETS AND REFERENCE MATERIAL

    [BSC] Sample forms found in “A Guide to the California Green Building Standards Code (Nonresidential)” located at https://www.dgs.ca.gov/BSC/Resources/Page-Content/Building-Standards-Commission-Resources-List-Folder/CALGreen may be used to assist in documenting compliance with the waste management plan and other provisions of this code.

    [HCD 1] Sample forms located at www.hcd.ca.gov/building-standards/calgreen/cal-green-forms.shtml may be used to assist in documenting compliance with CALGreen . WORKSHEET (WS-1) BASELINE WATER USE

Frequently asked questions

Where do I get the official WS‑1 form to attach to permit documents?

The official WS‑1 worksheet is in Chapter 8 of the CALGreen code (the Baseline Water Use form). The code package includes sample forms; HCD also posts sample CALGreen forms on its website.

Must I use the WS‑1 baseline values even if I have measured higher or lower flows?

Yes — WS‑1 provides the regulatory baseline flow rates to calculate BWU. For a performance demonstration you start from that WS‑1 baseline and then show your proposed reduced water use on WS‑2.

How do I determine occupant counts to use on WS‑1?

For nonresidential occupancies the worksheet directs you to Table 4‑1, Chapter 4 of the California Plumbing Code for occupant load factors. Use that CPC table to fill the occupant column on WS‑1.

What if I install waterless (nonwater) urinals?

Nonwater urinals can be entered as 0.0 gal/flush where allowed; WS‑2 includes a row for nonwater-supplied urinals. Document approval and installation per the Plumbing Code and CALGreen notes.

Can I use a prescriptive fixture schedule instead of the performance calculation?

Yes — the Appendix allows a prescriptive path (fixture-by-fixture maximums) for certain voluntary tiers (e.g., Tier 1). But the performance method uses WS‑1 to establish BWU and WS‑2 to show the required percent reduction.

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