CPC · California Plumbing Code

Water closets and urinals: prohibited types, flush valves, and spud requirements

Q: Are trough urinals ever allowed?

No. The CPC explicitly prohibits trough urinals . If a project claims a historical exception, consult the historical‑building provisions and the AHJ. § 405.2

Q: Can one flushometer valve operate two urinals?

No. The CPC states that no manually controlled flushometer valve shall be used to flush more than one urinal ; each urinal requires its own approved self‑closing valve. § 413.2

Q: What standard governs spuds and flush valves?

The code references ASME A112.19.5 for Flush Valves and Spuds , and maps that standard to the flush tank/valve provisions in § 413.3 ; specify products listed to that standard.

Q: What makes a seat acceptable for public water closets?

Seats must be properly sized for the bowl , smooth , and non‑absorbent ; public bowls should use elongated seats and either open front seats or automatic cover dispensers. § 411.3

The CPC forbids water closets and urinals that trap sewage or hide seals (no trough urinals, no invisible seals). Fixtures relying on trap siphonage must use approved flushometer valves or tanks, and spuds/flush valves must meet the ASME/ASSE/CSA standards the code references (see §§ 405.1, 405.2, 411.3 and 413.3).

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Last reviewed: July 6, 2026

What the code requires — 2–4 sentences

In plain English: the California Plumbing Code prohibits certain fixture designs that trap sewage or are unhygienic (for example, fixtures with an invisible seal, trough urinals, or unventilated water closets). Fixtures that rely on trap siphonage must be served by approved flushing devices (flushometer valve, flushometer tank, or flush tank) and those flushing devices and associated spuds/flush valves are controlled by referenced standards. These mandates are established in § 405.1, § 405.2, § 411.3, and § 413.3 of the CPC.

The single most important rule: do not install water closets or urinals that create hidden trap seals or unventilated spaces — they are expressly prohibited; where trap siphonage is relied upon, install code-compliant flushing devices and spuds per the referenced standards.

Requirements in detail

Prohibited fixture types (what you cannot install)

Water closets with an invisible seal, an unventilated space, walls not thoroughly washed at each discharge, or any water closet that might permit siphonage of the bowl back into the tank are prohibited. See § 405.1.
Urinals that are trough urinals or have an invisible seal are prohibited. See § 405.2.

Flush valves, flush tanks and flushometer valves (when they are required and what standard they must meet)

Any fixture that relies on trap siphonage to discharge must be provided with a flushometer valve, flushometer tank, or flush tank capable of supplying sufficient water quantity and rate to flush and refill the trap. See § 413.1.
Flushometer valves and flushometer tanks must comply with listed standards (ASSE/ASME/CSA) and be installed in accordance with anti‑siphon/backflow requirements. No manually controlled flushometer may flush more than one urinal; urinal flush valves must be approved, self‑closing, and discharge a predetermined quantity of water. Flushometers must be accessible for repair and include means for regulating flow. See § 413.2.
The CPC ties specific standards for flush valves and spuds to the flush‑device provisions; § 413.3 references applicable standards for flush tanks, valves and spuds (see referenced standards table). The standard for flush valves and spuds is ASME A112.19.5 (Flush Valves and Spuds), which is identified in the CPC referenced‑standards table for § 413.3.

Water‑closet seats and related fixture finish requirements

Water closet seats must be properly sized for the bowl type and constructed of smooth, non‑absorbent material. For public use, seats shall be elongated and either open‑front or equipped with an automatic seat cover dispenser. See § 411.3.

Quick decision table (decision‑relevant dimensions / values)

Decision factor	Rule / value	Code Reference
Prohibited water‑closet features	Invisible seal; unventilated space; walls not washed each discharge; siphonage back to tank	§ 405.1
Prohibited urinal types	Trough urinals; urinals with invisible seals	§ 405.2
Required flushing device if trap siphonage used	Flushometer valve, flushometer tank, or flush tank that supplies sufficient quantity and rate	§ 413.1
Flushometer valve standard & controls	Flushometers comply with ASSE/ASME/CSA (self‑closing for urinals; one valve per urinal; flow regulation)	§ 413.2
Spuds and flush‑valve product standard	Flush Valves and Spuds per ASME A112.19.5 (see referenced standards mapped to § 413.3)	§ 413.3 (referenced standards)
Water closet seat material / shape	Properly sized; smooth, non‑absorbent; public bowls elongated; open front or auto cover	§ 411.3

Exceptions & special cases

Historical buildings: historically accurate original or reproduction water closets, urinals, and flushometer valves are permitted in qualified historical buildings where approved by the enforcing agency. See historical‑building provisions.
Nonwater (waterless) urinals: these have separate requirements (liquid barrier sealant, maintenance, rough‑in provision for future retrofit water service, and an upstream water fixture to assure drain flow). They are covered in the CPC section on nonwater urinals (not part of the 405/413 prohibitions, but important when selecting urinal type).
Flushometer valves should not be used where water pressure is insufficient to operate them properly. Sensor‑operated flush valves must be capable of functioning during loss of normal power. See § 413.2.

If a specific product or spud has uncertain compliance, the code requires adherence to the listed standards; consult the standard (ASME A112.19.5 and the ASSE/ASME/CSA standards cited) and the Authority Having Jurisdiction for acceptability.

Common mistakes

Installing a trough urinal or any fixture with an invisible seal thinking it’s acceptable — the CPC expressly prohibits these. (Do not do this.)
Using one manually controlled flushometer valve to serve multiple urinals — not permitted; each urinal requires its own approved self‑closing valve.
Specifying a seat that does not match the bowl shape or is made of absorbent material (public fixtures must use elongated, smooth, non‑absorbent seats).
Forgetting to verify that flush valves, spuds and tanks conform to the referenced standards (e.g., ASME A112.19.5 for spuds/flush valves). The CPC relies on those standards via § 413.3.

Worked example — specifying a public single‑stall water closet with a flushometer

Scenario: a designer specifies a wall‑hung water closet for a public restroom. Requirements to check and actions to take:

Fixture type: choose a public elongated bowl (public use must be elongated). Confirm bowl complies with ASME A112.19.2/CSA B45.1. Reference: § 411.1 / § 411.3.
Seat: specify a smooth, non‑absorbent elongated seat, open‑front or with an auto cover dispenser. Reference: § 411.3.
Flushing device: the fixture relies on trap siphonage (wall‑hung). Provide a flushometer valve sized to deliver the required volume/rate and conforming to ASSE/ASME/CSA standards called out in the CPC. Ensure the valve is accessible for repair and has a means to regulate flow. Reference: § 413.1 and § 413.2.
Spud / flush valve hardware: specify flush valve and spud that meet ASME A112.19.5 (the CPC references this standard for flush valves and spuds under § 413.3). Confirm manufacturer’s documentation listing ASME A112.19.5 compliance. Reference: § 413.3 (referenced standards).
Pressure / operation: verify building water pressure is adequate for the chosen flushometer (the CPC prohibits using flushometers where pressure is insufficient). If sensor‑operated, confirm it can operate during loss of normal power. Reference: § 413.2.

Related provisions

§ 405.1 — Prohibited water closets.
§ 405.2 — Prohibited urinals.
§ 411.3 — Water closet seats (size/material/shape).
§ 413.1 – § 413.3 — Flushing devices, flushometer valves, and flush tanks/spud references (including standards linkage).
§ 412.1.3 — Nonwater urinal requirements (liquid barrier sealant, maintenance, upstream water fixture, rough‑in for retrofit).
Historical building allowance for original or reproduction fixtures (qualified historic structures).

Code references

Grounded in the retrieved California Plumbing Code — click a citation to read the verbatim passage:

CPC § 18.9 High relevance — show source text
Protectors, insulators, or both shall comply with ASME A112.18.9 or ASTM C1822. [HCD 1-AC] Specific requirements regard- ing accommodations for persons with disabilities are contained in Chapter 11A of the California Building Code.

404.0 Waste Fittings and Overflows. 404.1 Waste Fittings. Waste fittings shall comply with ASME A112.18.2/CSA B125.2, ASTM F409 or Table 701.2 for aboveground drainage piping and fittings. 404.2 Overflows. Where a fixture is provided with an overflow, the overflow shall comply with Section 404.2.1 or Section 404.2.2.

404.2.1 Sinks, Lavatories, and Bathtubs. The waste shall be so arranged that the standing water in the fixture shall not rise in the overflow where the stopper is closed or remain in the overflow where the fixture is empty. The overflow pipe from a fixture shall be connected to the house or inlet side of the fixture trap.

404.2.2 Water Closets and Urinals. Overflows on flush tanks shall be permitted to discharge into the water closets or urinals served by them.

405.0 Prohibited Fixtures.

405.1 Prohibited Water Closets. Water closets having an invisible seal or an unventilated space or having walls which are not thoroughly washed at each discharge shall be prohibited. A water closet that might permit siphonage of the contents of the bowl back into the tank shall be prohibited. 405.2 Prohibited Urinals. Trough urinals and urinals with an invisible seal shall be prohibited.

405.3 Miscellaneous Fixtures. Fixed wooden, or tile wash sinks for domestic use shall not be installed in a building designed or used for human habitation. No sheet metal-lined wooden bathtub shall be installed or reconnected. No dry or chemical closet (toilet) shall be installed in a building used for human habitation unless first approved by the Health Officer.

60 2025 CALIFORNIA PLUMBING CODE

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

PLUMBING FIXTURES AND FIXTURE FITTINGS

406.0 Special Fixtures and Specialties.

406.1 Water and Waste Connections. Baptisteries, ornamental and lily ponds, aquaria, ornamental fountain basins, and similar fixtures and specialties requiring water, waste connections, or both shall be submitted for approval to the Authority Having Jurisdiction prior to installation.

406.2 Special Use Sinks. Restaurant kitchen and other special use sinks shall be permitted to be made of approvedtype bonderized and galvanized sheet steel of not less than No. 16 U.S. gauge (0.0635 inches) (1.6 mm). Sheet-metal plumbing fixtures shall be adequately designed, constructed, and braced in an approved manner to accomplish their intended purpose.

406.3 Special Use Fixtures. Special use fixtures shall be made of one of the following:

(1) Soapstone

(2) Chemical stoneware

(3) Copper-based alloy

(4) Nickel-based alloy

(5) Corrosion-resistant steel

(6) Other materials suited for the intended use of the fixture

406.4 Zinc Alloy Components. Zinc alloy components shall comply with applicable nationally recognized standards and shall be used in accordance with their listing.
CPC § 402.6.1. High relevance — show source text
402.6.1. 2 Shall be listed to EPA WaterSense Specification for Tank-Type Toilet or Specification for Flushometer-Valve Water Closets. 3 Shall be listed to EPA WaterSense Flushing Urinal Specification. Nonwater urinals shall comply with specifications listed in Section L 402.3.1. 4 See Section L 402.4. 5 Shall be listed to EPA WaterSense High-Efficiency Lavatory Faucet Specification.

L 402.2 Water Closets. No water closet shall have an effective flush volume exceeding 1.28 gallons per flush (gpf) (4.8 Lpf). L 402.2.1 Gravity, Pressure Assisted, and Elec- tro-Hydraulic Tank Type Water Closets. Gravity, pressure assisted, and electro-hydraulic tank-type water closets shall have a maximum effective flush volume of

TABLE L 402.1

MAXIMUM FIXTURE AND FIXTURE FITTINGS FLOW RATES

For SI units: 1 gallon per minute = 0.06 L/s, 1 pound-force per square inch = 6.8947 kPa, 1 inch = 25.4 mm, 1 gallon = 3.785 L

Notes: 1 Shall be listed to EPA WaterSense Specification for Showerheads. For multiple showerheads serving one shower compartment see Section L

402.6.1. 2 Shall be listed to EPA WaterSense Specification for Tank-Type Toilet or Specification for Flushometer-Valve Water Closets. 3 Shall be listed to EPA WaterSense Flushing Urinal Specification. Nonwater urinals shall comply with specifications listed in Section L 402.3.1. 4 See Section L 402.4. 5 Shall be listed to EPA WaterSense High-Efficiency Lavatory Faucet Specification.

not more than 1.28 gallons (4.8 Lpf) of water per flush in accordance with ASME A112.19.2/CSA B45.1 or

ASME A112.19.14 and shall be listed to the EPA WaterSense Specification for Tank-Type Toilets. The effective flush volume for dual flush toilets is defined as the composite, average flush volume of two reduced flushes and one full flush.

L 402.2.2 Flushometer-Valve Activated Water

Closets. Flushometer-valve activated water closets

shall have a maximum flush volume of not more than 1.28 gallons (4.8 Lpf) of water per flush in accordance with ASME A112.19.2/CSA B45.1 and shall be listed to the EPA WaterSense Specification for FlushometerValve Water Closets.

L 402.3 Urinals. Urinals shall have a maximum flush volume of not more than 0.5 gallon (1.9 Lpf) of water per flush in accordance with ASME A112.19.2/CSA B45.1 or CSA B45.5/IAPMO Z124. Flushing urinals shall be listed to the EPA WaterSense Flushing Urinal Specification.

L 402.3.1 Nonwater Urinals. Nonwater urinals shall comply with ASME A112.19.3/CSA B45.4, ASME A112.19.19, or CSA B45.5/IAPMO Z124. Nonwater urinals shall be cleaned and maintained in accordance with
CPC § 402.10 High relevance — show source text
402.10 Slip Joint Connections. Fixtures having concealed slip joint connections shall be provided with an access panel or utility space not less than 12 inches (305 mm) in its least dimension and so arranged without obstructions as to make such connections accessible for inspection and repair. 402.11 Future Fixtures. Where provisions are made for the future installation of fixtures, those provided for shall be considered in determining the required sizes of the drain and water supply piping. Construction for future installations shall be terminated with a plugged fitting or fittings. Where the plugged

fitting is at the point where the trap of a fixture is installed, the plumbing system for such fixture shall be complete and be in accordance with the plumbing requirements of this code.

403.0 Accessible Plumbing Facilities. 403.1 General. Where accessible facilities are required in applicable building regulations, the facilities shall be installed in accordance with those regulations. [HCD 1-AC] For spe- cific requirements regarding accommodations for persons with disabilities, see Chapter 11A of the California Building Code. 403.2 Fixtures and Fixture Fittings for Persons with Disabilities. Plumbing fixtures and fixture fittings for persons with disabilities shall be in accordance with ICC A117.1 and the applicable standards referenced in Chapter 4. [HCD 1-AC] Specific requirements regarding accommodations for persons with disabilities are contained in Chapter 11A of the California Building Code. 403.3 Exposed Pipes and Surfaces. Water supply and drainpipes under accessible lavatories and sinks shall be insulated or otherwise be configured to protect against contact. Protectors, insulators, or both shall comply with ASME A112.18.9 or ASTM C1822. [HCD 1-AC] Specific requirements regard- ing accommodations for persons with disabilities are contained in Chapter 11A of the California Building Code.

404.0 Waste Fittings and Overflows. 404.1 Waste Fittings. Waste fittings shall comply with ASME A112.18.2/CSA B125.2, ASTM F409 or Table 701.2 for aboveground drainage piping and fittings. 404.2 Overflows. Where a fixture is provided with an overflow, the overflow shall comply with Section 404.2.1 or Section 404.2.2.

404.2.1 Sinks, Lavatories, and Bathtubs. The waste shall be so arranged that the standing water in the fixture shall not rise in the overflow where the stopper is closed or remain in the overflow where the fixture is empty. The overflow pipe from a fixture shall be connected to the house or inlet side of the fixture trap.

404.2.2 Water Closets and Urinals. Overflows on flush tanks shall be permitted to discharge into the water closets or urinals served by them.

405.0 Prohibited Fixtures.

405.1 Prohibited Water Closets. Water closets having an invisible seal or an unventilated space or having walls which are not thoroughly washed at each discharge shall be prohibited. A water closet that might permit siphonage of the contents of the bowl back into the tank shall be prohibited. 405.2 Prohibited Urinals. Trough urinals and urinals with an invisible seal shall be prohibited.
CPC § 1.28 High relevance — show source text
not more than 1.28 gallons (4.8 Lpf) of water per flush in accordance with ASME A112.19.2/CSA B45.1 or

ASME A112.19.14 and shall be listed to the EPA WaterSense Specification for Tank-Type Toilets. The effective flush volume for dual flush toilets is defined as the composite, average flush volume of two reduced flushes and one full flush.

L 402.2.2 Flushometer-Valve Activated Water

Closets. Flushometer-valve activated water closets

shall have a maximum flush volume of not more than 1.28 gallons (4.8 Lpf) of water per flush in accordance with ASME A112.19.2/CSA B45.1 and shall be listed to the EPA WaterSense Specification for FlushometerValve Water Closets.

L 402.3 Urinals. Urinals shall have a maximum flush volume of not more than 0.5 gallon (1.9 Lpf) of water per flush in accordance with ASME A112.19.2/CSA B45.1 or CSA B45.5/IAPMO Z124. Flushing urinals shall be listed to the EPA WaterSense Flushing Urinal Specification.

L 402.3.1 Nonwater Urinals. Nonwater urinals shall comply with ASME A112.19.3/CSA B45.4, ASME A112.19.19, or CSA B45.5/IAPMO Z124. Nonwater urinals shall be cleaned and maintained in accordance with

the manufacturer’s instructions after installation. Where nonwater urinals are installed, they shall have a water distribution line roughed-in to the urinal location at a height not less than 56 inches (1422 mm) to allow for the installation of an approved backflow prevention device in the event of a retrofit. Such water distribution lines

shall be installed with shutoff valves located as close as possible to the distributing main to prevent the creation of dead ends. Where nonwater urinals are installed, not less than one water supplied fixture rated at not less than 1 drainage fixture unit (DFU) shall be installed upstream on the same drain line to facilitate drain line flow and rinsing. L 402.3.2 Nonwater Urinals with Drain Cleansing Action. Nonwater urinals with drain cleansing action shall comply with ASME A112.19.19 and shall be cleaned, maintained, and installed in accordance with the manufacturer’s installation instructions.

L 402.4 Residential Kitchen Faucets. The maximum

flow rate of residential kitchen faucets shall not exceed 1.8 gallons per minute (gpm) (6.8 L/m) at 60 pounds-force per square inch (psi) (414 kPa). Kitchen faucets are permitted to temporarily increase the flow above the maximum rate, but not to exceed 2.2 gpm (8.3 L/m) at 60 psi (414 kPa), and shall revert to a maximum flow rate of 1.8 gpm (6.8 L/m) at 60 psi (414 kPa) upon valve closure.

L 402.5 Lavatory Faucets. The maximum water flow rate of faucets shall comply with Section L 402.5.1 and Section L 402.5.2.

CPC § 402.1 High relevance — show source text

TABLE L 402.1

MAXIMUM FIXTURE AND FIXTURE FITTINGS FLOW RATES

FIXTURE TYPE	FLOW RATE
Showerheads	2.0 gpm at 80 psi1
Kitchen faucets residential4	1.8 gpm at 60 psi
Lavatory faucets residential5	1.5 gpm at 60 psi
Lavatory faucets other than residential	0.5 gpm at 60 psi
Metering faucets	0.25 gallons/cycle
Metering faucets for wash fountains	One 0.25 gallons/cycle fixture fit- ting for each 20 inches rim space
Wash fountains	One 2.2 gpm at 60 psi fixture fit- ting for each 20 inches rim space
Water Closets	1.28 gallons/flush2
Urinals	0.5 gallons/flush3
Commercial Pre-Rinse Spray Valves	See Section L 402.9

For SI units: 1 gallon per minute = 0.06 L/s, 1 pound-force per square inch = 6.8947 kPa, 1 inch = 25.4 mm, 1 gallon = 3.785 L

Notes: 1 Shall be listed to EPA WaterSense Specification for Showerheads. For multiple showerheads serving one shower compartment see Section L

402.6.1. 2 Shall be listed to EPA WaterSense Specification for Tank-Type Toilet or Specification for Flushometer-Valve Water Closets. 3 Shall be listed to EPA WaterSense Flushing Urinal Specification. Nonwater urinals shall comply with specifications listed in Section L 402.3.1. 4 See Section L 402.4. 5 Shall be listed to EPA WaterSense High-Efficiency Lavatory Faucet Specification.

L 402.2 Water Closets. No water closet shall have an effective flush volume exceeding 1.28 gallons per flush (gpf) (4.8 Lpf). L 402.2.1 Gravity, Pressure Assisted, and Elec- tro-Hydraulic Tank Type Water Closets. Gravity, pressure assisted, and electro-hydraulic tank-type water closets shall have a maximum effective flush volume of

TABLE L 402.1

MAXIMUM FIXTURE AND FIXTURE FITTINGS FLOW RATES

For SI units: 1 gallon per minute = 0.06 L/s, 1 pound-force per square inch = 6.8947 kPa, 1 inch = 25.4 mm, 1 gallon = 3.785 L

Notes: 1 Shall be listed to EPA WaterSense Specification for Showerheads. For multiple showerheads serving one shower compartment see Section L

CPC § 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.
CPC § 4-8 High relevance — show source text
4-8 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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

4 RESIDENTIAL MANDATORY MEASURES

DIVISION 4.3 – WATER EFFICIENCY AND CONSERVATION

SECTION 4.301—GENERAL

4.301.1 Scope. The provisions of this chapter shall establish the means of conserving water used indoors, outdoors and in wastewater conveyance.

SECTION 4.302—DEFINITIONS

4.302.1 Definitions. Reserved.

SECTION 4.303—INDOOR WATER USE

4.303.1 Water conserving plumbing fixtures and fittings. Plumbing fixtures (water closets and urinals) and fittings (faucets and showerheads) shall comply with Sections 4.303.1.1, 4.303.1.2, 4.303.1.3 and 4.303.1.4.

Note: All noncompliant plumbing fixtures in any residential real property shall be replaced with water-conserving plumbing fixtures. Plumbing fixture replacement is required prior to issuance of a certificate of final completion, certificate of occupancy, or final permit approval by the local building department. See Civil Code Section 1101.1, et seq., for the definition of a noncompliant plumbing fixture, types of residential buildings affected and other important enactment dates.

4.303.1.1 Water closets. The effective flush volume of all water closets shall not exceed 1.28 gallons per flush. Tank-type water closets shall be certified to the performance criteria of the US EPA WaterSense Specification for Tank-type Toilets.

Note: The effective flush volume of dual flush toilets is defined as the composite, average flush volume of two reduced flushes and one full flush.

4.303.1.2 Urinals. The effective flush volume of wall-mounted urinals shall not exceed 0.125 gallons per flush. The effective flush volume of all other urinals shall not exceed 0.5 gallons per flush.

4.303.1.3 Showerheads.

4.303.1.3.1 Single showerhead. Showerheads shall have a maximum flow rate of not more than 1.8 gallons per minute at 80 psi. Showerheads shall be certified to the performance criteria of the US EPA WaterSense Specification for Showerheads.

4.303.1.3.2 Multiple showerheads serving one shower. When a shower is served by more than one showerhead, the combined flow rate of all showerheads and/or other shower outlets controlled by a single valve shall not exceed 1.8 gallons per minute at 80 psi, or the shower shall be designed to allow only one shower outlet to be in operation at a time.

Note: A hand-held shower shall be considered a showerhead.

4.303.1.4 Faucets.

4.303.1.4.1 Residential lavatory faucets. The maximum flow rate of residential lavatory faucets shall not exceed 1.2 gallons per minute at 60 psi. The minimum flow rate of residential lavatory faucets shall not be less than 0.8 gallons per minute at 20 psi.
CPC § 5.303 High relevance — show source text
GRAYWATER.

METERING FAUCET.

MODEL WATER EFFICIENT LANDSCAPE ORDINANCE (MWELO).

POTABLE WATER.

SPECIAL LANDSCAPE AREA (SLA). [DSA-SS]

SUBMETER.

SECTION 5.303—INDOOR WATER USE

5.303.1 Meters. Separate submeters or metering devices shall be installed for the uses described in Sections 5.303.1.1 and 5.303.1.2. 5.303.1.1 New buildings or additions in excess of 50,000 square feet. Separate submeters shall be installed as follows:
1. For each individual leased, rented or other tenant space within the building projected to consume more than 100 gal/day (380 L/day), including, but not limited to, spaces used for laundry or cleaners, restaurant or food service, medical or dental office, laboratory, or beauty salon or barber shop.
2. Where separate submeters for individual building tenants are unfeasible, for water supplied to the following subsystems: a. Makeup water for cooling towers where flow through is greater than 500 gpm (30 L/s). b. Makeup water for evaporative coolers greater than 6 gpm (0.04 L/s). c. Steam and hot-water boilers with energy input more than 500,000 Btu/h (147 kW). 5.303.1.2 Excess consumption. A separate submeter or metering device shall be provided for any tenant within a new building or within an addition that is projected to consume more than 1,000 gal/day.
5.303.2 Reserved.

5.303.3 Water conserving plumbing fixtures and fittings. Plumbing fixtures (water closets and urinals) and fittings (faucets and showerheads) shall comply with the following: 5.303.3.1 Water closets. The effective flush volume of all water closets shall not exceed 1.28 gallons per flush. Tank-type water closets shall be certified to the performance criteria of the US EPA WaterSense Specification for Tank-Type Toilets. Note: The effective flush volume of dual flush toilets is defined as the composite, average flush volume of two reduced flushes and one full flush.

5.303.3.2 Urinals.

5.303.3.2.1 Wall-mounted urinals. The effective flush volume of wall-mounted urinals shall not exceed 0.125 gallons per flush.

5.303.3.2.2 Floor-mounted urinals. The effective flush volume of floor-mounted or other urinals shall not exceed 0.5 gallons per flush.

5.303.3.3 Showerheads.

5.303.3.3.1 Single showerhead. Showerheads shall have a maximum flow rate of not more than 1.8 gallons per minute at 80 psi. Showerheads shall be certified to the performance criteria of the US EPA WaterSense Specification for Showerheads. 5.303.3.3.2 Multiple showerheads serving one shower. When a shower is served by more than one showerhead, the combined flow rate of all showerheads and/or other shower outlets controlled by a single valve shall not exceed 1.8 gallons per minute at 80 psi, or the shower shall be designed to allow only one shower outlet to be in operation at a time.

Note: A hand-held shower shall be considered a showerhead.

5.303.3.4 Faucets and fountains.
CPC § 501.3 High relevance — show source text
Openable windows and vents to the outside shall be provided with flyproof screens of not less than number 16 mesh.

E 501.3 Water Closets. Not less than one water closet shall be provided for each sex up to the first 25 sites. For each additional 25 sites not provided with sewer connections, an additional water closet shall be provided.

E 501.3.1 Application. Water closets shall be of an approved, elongated bowl type and shall be provided with seats with open fronts. E 501.3.2 Compartment. Each water closet shall be in a separate compartment and shall be provided with a latched door for privacy. A holder or dispenser for toilet paper shall be provided. Dividing walls or partitions shall be not less than 5 feet (1524 mm) high and shall be separated from the floor by a space not exceeding 12 inches (305 mm). E 501.3.3 Size. Water closet compartments shall be not less than 30 inches (762 mm) in width [no water closet shall be set closer than 15 inches (381 mm) from its center to a side wall] and shall be not less than 30 inches (762 mm) of clear space in front of each water closet.

E 501.4 Lavatories. Where water-supplied water closets are provided, an equal number of lavatories shall be provided for up to six water closets. One additional lavatory shall be provided for each two water closets where more than six water closets are required. Each lavatory basin shall have a piped supply of potable water and shall drain into the drainage sys tem.

E 501.5 Urinals. Where separate facilities are provided for men and women, urinals shall be acceptable for not more than one-third of the water closets required in the men’s facilities, except that one urinal shall be permitted to be used to replace a water closet in a minimum park. Individual stall or wallhung types of urinals shall be installed. Floor-type trough units shall be prohibited.

E 501.6 Floors and Drains. The floors shall be constructed of material impervious to water and shall be easily cleanable. A building having water-supplied water closets shall be provided with a floor drain in the toilet room. This drain shall be provided with means to protect the trap seal in accordance with this code.

E 501.7 Shower Size. Each shower, where provided, shall have a floor area of 36 inches by 36 inches (914 mm by 914 mm), shall be capable of encompassing a 30 inch (762 mm) diameter circle and shall be of the individual type. The shower area shall be visually screened from view with a minimum floor area of 36 by 36 inches (914 mm by 914 mm) per shower. Each shall be provided with individual dressing areas screened from view and shall contain a minimum of one clothing hook and stool (or bench area). E 501.7.1 Drainage Connection. Each shower area shall be designed to minimize the flow of water into the dressing area and shall be connected to the drainage system using a properly trapped and vented inlet. Each such area shall have an impervious, skid-resistant surface; wooden racks (duck boards) over shower floors shall be prohibited. E 501.8 Drinking Fountains. Where provided, drinking fountains shall be in accordance with the requirements of this code.

2025 CALIFORNIA PLUMBING CODE 413
CPC § 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.

CPC § 1.8 Medium 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.

CPC § 6-2017 Medium relevance — show source text
6-2017 (R2021)|Flexible Water Connectors|Piping|604.5, 604.13| |ASME A112.18.8-2020|Sanitary Waste Valves for Plumbing Drainage Systems|Sanitary Waste
Valves|814.4| |ASME A112.18.9-2011
(R2017)|Protectors/Insulators for Exposed Waste and Supplies on
Accessible Fixtures|Miscellaneous|403.3| |ASME A112.19.1-
2018/CSA B45.2-2018|Enameled Cast Iron and Enameled Steel Plumbing Fixtures|Fixtures|407.1, 408.1, 409.1,
415.1, 420.1| |ASME A112.19.2-
2018/CSA B45.1-2018|Ceramic Plumbing Fixtures|Fixtures|407.1, 408.1, 409.1,
410.1, 411.1, 412.1,
415.1, 420.1| |ASME A112.19.3-
2017/CSA B45.4-2017|Stainless Steel Plumbing Fixtures|Fixtures|407.1, 408.1, 409.1,
410.1, 411.1, 415.1,
420.1| |ASME A112.19.5-
2017/CSA B45.15-2017|Flush Valves and Spuds for Water Closets, Urinals, and Tanks|Fixtures|413.3| |ASME A112.19.7-
2020/CSA B45.10-2020|Hydromassage Bathtub Systems|Fixtures|409.1, 409.6.1| |ASME A112.19.12-2014
(R2019)|Wall Mounted, Pedestal Mounted, Adjustable, Elevating, Tilt-
ing, and Pivoting Lavatory, Sink, and Shampoo Bowl Carrier
Systems and Drain Waste Systems|Fixtures|407.1, 420.1| |ASME A112.19.14-2013
(R2018)|Six-Liter Water Closets Equipped with a Dual Flushing Device|Fixtures|411.2.1| |ASME A112.19.15-2012
(R2017)|Bathtubs/Whirlpool Bathtubs with Pressure Sealed Doors|Fixtures|409.1| |ASME A112.19.19-2016
(R2021)|Vitreous China Nonwater Urinals|Fixtures|412.1, 412.1.2| |ASSE 1002-2020/ASME
A112.1002-2020/CSA
B125.12-2020|Anti-Siphon Fill Valves for Water Closet Tanks|Backflow Protection|413.3, Table 603.2| |ASME A112.36.2M-1991
(R2017)|Cleanouts|DWV Components|Table 707.2, 707.4.1| |ASSE 1016-2017/ASME
A112.1016-2017/CSA
B125.16-2017|Automatic Compensating Valves for Individual Showers and
Tub/Shower Combinations|Valves|408.4, 408.4.2(1)| |ASSE 1037-2020/ASME
A112.

Frequently asked questions

Are trough urinals ever allowed?

No. The CPC explicitly prohibits trough urinals. If a project claims a historical exception, consult the historical‑building provisions and the AHJ. § 405.2

Can one flushometer valve operate two urinals?

No. The CPC states that no manually controlled flushometer valve shall be used to flush more than one urinal; each urinal requires its own approved self‑closing valve. § 413.2

What standard governs spuds and flush valves?

The code references ASME A112.19.5 for Flush Valves and Spuds, and maps that standard to the flush tank/valve provisions in § 413.3; specify products listed to that standard.

What makes a seat acceptable for public water closets?

Seats must be properly sized for the bowl, smooth, and non‑absorbent; public bowls should use elongated seats and either open front seats or automatic cover dispensers. § 411.3

If I install a nonwater urinal, do I still need a water line?

Yes. The CPC requires a water distribution line rough‑in to each nonwater urinal location to allow future installation of backflow protection; additional drainage and upstream water‑supplied fixture requirements also apply.

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Related in the CPC

Lavatory application, water consumption, and hot‑water limitations

Kitchen, service, and floor sink sizing, waste outlets, and strainers

Shower and bathtub fitting, consumption, and referenced standards

Requirements by fixture type: lavatories, water closets, showers, sinks, and specialty fixtures

California Plumbing Code