Section A5.303

INDOOR WATER USE

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 plumb

ing 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:

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
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.

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.

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APPENDIX A5—NONRESIDENTIAL VOLUNTARY MEASURES

TABLE A5.303.2.2 WATER USE BASELINE (PERFORMANCE METHOD) ³

FIXTURE TYPE	BASELINE FLOW RATE	DURATION	DAILY USES	OCCUPANTS2
Showerheads	1.8 gpm @ 80 psi	5 min.	1	X2a
Lavatory faucets nonresidential	0.5 gpm @ 60 psi	.25 min.	3	X
Kitchen faucets	1.8 gpm @ 60 psi	4 min.	1	X2b
Replacement aerators	2 gpm @ 60 psi			X
Wash fountains	1.8 gpm/20 [rim space (in.) @ 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

The daily use number shall be increased to three if urinals are not installed in the room.
Refer to Table 4-1, Chapter 4, 2022 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.

TABLE A5.303.2.3.1 FIXTURE FLOW RATES (PRESCRIPTIVE METHOD)

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.) @ 60 psi]
Metering faucets	0.20 gallons/cycle	0.18 gallons/cycle
Metering faucets for wash fountains	0.20 gallons/cycle/20 [rim space (in.) @ 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

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.
See Table A5.503.2.2 for additional notes and references.
Where complying faucets are unavailable, aerators rated at 0.35 gpm or other means may be used to achieve reduction.
Floor-mounted urinals @ 0.5 GPF or wall-mounted urinals @ 0.125 GPF.

APPENDIX A5-12 2022 CALIFORNIA GREEN BUILDING STANDARDS CODE

APPENDIX A5—NONRESIDENTIAL VOLUNTARY MEASURES

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.