CPC · California Plumbing Code

What venting, cleanability and anti-splash requirements apply to receptors?

The CPC requires that indirect-waste vents go separately to outside air and not tie into sewer-connected vents; indirect-waste runs longer than 5 ft but less than 15 ft must be directly trapped (trap need not be vented); receptors receiving indirect wastes must be approved, shaped and sized to prevent splash/flooding and placed where they’re accessible for cleaning; clothes-washer standpipes and trap rough-ins have specific height limits. All requirements are in **§ 803.3** and **§ 804.1**.

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Last reviewed: July 6, 2026

What the code requires — 2-4 sentences

Indirect-waste piping must be sized and vented separately from sewer-connected vents, and short indirect-waste runs have specific trap and sizing rules — see § 803.3. Standpipe-type receptors that receive indirect wastes must be of a shape and capacity to prevent splashing or flooding and be readily accessible for inspection and cleaning — see § 804.1. Both sections place dimensional limits (for clothes-washer standpipes and trap rough-ins) and require cleanouts at changes of direction.

Receptors for indirect wastes must stop splash/flooding and be easy to clean; indirect-waste vents must go to outside air and certain pipe lengths must be trapped. See § 803.3 and § 804.1.

Requirements in detail

Key defined terms (first use bolded)

  • Indirect waste pipe — a waste that discharges indirectly to a receptor (covered by § 803.3).
  • Standpipe receptor — the receptor (fixture) that receives the indirect waste discharge (covered by § 804.1).
  • Trap — a water seal device associated with the receptor or indirect-waste piping where required.
  • Cleanout — an access for flushing/cleaning at changes of direction in indirect-waste piping.

Summary table — decision-relevant dimensions and values

Decision dimension Requirement / value Code Reference
Venting of indirect waste piping Vents from indirect waste piping shall extend separately to the outside air; no vent from indirect waste piping shall combine with a sewer‑connected vent. § 803.3
Trap required by pipe length Indirect waste pipes > 5 ft (1524 mm) but < 15 ft (4572 mm) — must be directly trapped (trap need not be vented). § 803.3
Minimum pipe diameter (short runs) Indirect waste pipes < 15 ft (4572 mm) in length must be at least the diameter of the drain outlet or tailpiece, and in no case less than 1/2 inch (15 mm). § 803.3
Cleanouts Angles and changes of direction in indirect waste pipes shall be provided with cleanouts to permit flushing/cleaning. § 803.3
Receptor shape & capacity Receptors shall be approved for the use proposed and of such shape and capacity as to prevent splashing or flooding. (No numeric capacity specified.) § 804.1
Accessibility for cleaning Receptors shall be located where they are readily accessible for inspection and cleaning. § 804.1
Clothes-washer standpipe height Standpipe for clothes washer shall not extend more than 30 in. (762 mm) or less than 18 in. (457 mm) above its trap weir. § 804.1
Clothes-washer trap rough-in No trap for a clothes‑washer standpipe shall be installed below the floor; rough‑in must be not less than 6 in. (152 mm) and not more than 18 in. (457 mm) above the floor. § 804.1
Location restriction No indirect waste receptor shall be installed in a toilet room, closet, cupboard, or storeroom, or in a portion of a building not in general use by occupants. Exception: clothes‑washer standpipes are allowed in toilet/bathroom areas when the washer is in the same room. § 804.1

Short elaborations

  • Venting: the code forbids combining an indirect-waste vent with a sewer-connected vent; indirect-waste vents must run separately to outdoors. This prevents cross-venting of sewage gases into the drainage vent system. § 803.3
  • Traps and lengths: a small range of lengths triggers a trap requirement: >5 ft and <15 ft must be trapped. For most short runs (<15 ft) the pipe diameter cannot be less than the fixture tailpiece or 1/2". § 803.3
  • Receptor performance: the CPC requires receptors be approved and sized/shaped to stop splash and flooding, but it does not give a numeric volume or geometric shape—approval and suitability are left to the product/manufacturer and the Authority Having Jurisdiction. § 804.1

Exceptions & special cases

  • Trap venting: when an indirect waste pipe is directly trapped because its length is between 5 ft and 15 ft, the code explicitly says such traps need not be vented. § 803.3
  • Location exception for clothes washers: although indirect waste receptors are generally prohibited from toilet rooms and similar spaces, standpipes for clothes washers are permitted in toilet/bathroom areas only when the washer is installed in the same room. § 804.1
  • What the code does not specify: there is no numeric "anti‑splash" dimension or required receptor volume in § 804.1 — compliance is by approval and demonstrated suitability (manufacturer/AHJ).

Common mistakes

  • Combining indirect-waste vents with sewer-connected vents. The code forbids that — vents for indirect wastes must run separately to the outside air (§ 803.3).
  • Forgetting cleanouts where piping changes direction; the code requires cleanouts at angles and changes of direction to permit flushing/cleaning (§ 803.3).
  • Installing a clothes-washer standpipe outside the 18–30 in. above‑weir range or setting the trap rough‑in below the floor or outside the 6–18 in. rough‑in range — both are specific limits in § 804.1.
  • Assuming a trap must be vented for every indirect waste run; for runs >5 ft and <15 ft the trap need not be vented (but must be provided). § 803.3
  • Relying on an unapproved receptor or one that hasn’t been demonstrated to prevent splashing — § 804.1 requires the receptor be approved for the use proposed.

Worked example — concrete scenario

Scenario: A dishwasher discharges to an indirect‑waste receptor via an indirect waste pipe that is 8 ft (2438 mm) long. The dishwasher tailpiece is 3/4 inch.

Apply the code:

  • Length is >5 ft and <15 ft, so the indirect waste pipe must be directly trapped, and that trap need not be vented. § 803.3
  • Because the run is <15 ft, the pipe diameter must be at least the diameter of the drain outlet (which is 3/4 in. here) — and in no case smaller than 1/2 in. — so use 3/4 in. or larger. § 803.3
  • If there is a bend in the run, provide a cleanout at that change of direction. § 803.3
  • The receptor selected must be approved and shaped/sized to prevent splashing when the dishwasher discharges. The receptor must be readily accessible for inspection and cleaning. (The code does not give a required receptor volume; use a product approved for dishwasher indirect waste.) § 804.1

If instead the indirect-waste run were 4 ft long, a direct trap would not be mandated by § 803.3, but the pipe would still have to meet the minimum diameter rule for runs under 15 ft.

Related provisions

  • § 803.0 — Indirect Waste Piping (scope/intro).
  • § 803.1 — Materials for indirect waste piping.
  • § 803.2 — Copper and copper-alloy joints for indirect wastes.
  • § 803.3 — Pipe size and length (venting, traps, cleanouts) — controlling vent/trap rules above. § 803.3
  • § 804.0 — Indirect Waste Receptors (section header).
  • § 804.1 — Standpipe receptors (shape/capacity/accessibility/location limits) — controlling receptor rules above. § 804.1
  • § 805.0 — Pressure drainage connections (related topic).
  • § 806.0 — Sterile equipment (references air gaps and similar requirements).

If you need the exact full text for any of these sections, I can pull the quoted lines from the CPC file for review. The summary above is grounded in the CPC provisions cited (see § 803.3 and § 804.1).

Code references

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

  • CPC § 2025 High relevance — show source text

    2025 CALIFORNIA PLUMBING CODE 477

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

    TCNA HANDBOOK CURBLESS SHOWER RECEPTORS

    Recommended Uses

    • For construction of a shower without a curb.

    Environmental Exposure Classifications

    • Res1, 2, 3; Com1, 2

    • May be suitable for Com3, Res5, and Com5 as determined by membrane and backing material manufacturers.

    • For Res4 and Com4, see SR613 and SR614.

    • For installations that may be exposed to staining, specify tile and grout suitable for exposure. Consult product manufacturers; see also “Product Selection Guides.”

    • For installations that may be exposed to mild chemical attack, specify epoxy grout and tile suitable for exposure. Consult product manufacturers; see also “Product Selection Guides.”

    Limitations

    • Facilitates construction of a curbless shower without adding floor height at restroom entryway, but does not inherently comply with Americans with Disabilities Act (ADA) Standards for Accessible Design. Follow ADA where ADA compliance is required or desired.

    • Refer to appropriate wall method for applicable limitations based on type of backing used—W201, W202E, W202I, W211, W221, W222, W231/W241, W243, W244C, W244E, W244F, W245, W246, and W247.

    Requirements

    • When glass tile is used, consult glass tile manufacturer for tile suitability over non-absorptive surface.

    • Bonded waterproof membrane must be continuous, including at changes in plane. Follow membrane manufacturer’s requirements for corners, seaming, and overlap.

    • Waterproof membrane inside shower area must extend to full height of tile assembly. Also, the floor and wall waterproofing must continue outside the immediate shower area one foot beyond the high point of the floor, but not beyond the tiled area. Additional waterproofing of floor and/or walls outside the shower area may be needed to effectively contain and evacuate shower water and splash water and to protect building materials. When additional waterproofing of floor and/or walls outside the shower area is desired or required, the building design professional must specify all areas to be waterproofed and indicate membrane termination points.

    • A secondary drain may be required outside the immediate shower area to facilitate evacuation of shower water and splash water that is not contained in the shower area due to curbless design. When required or desired, building design professional must specify type and location of secondary drain.

    • High point of the floor must be outside the shower area, i.e., beyond shower door or curtain, to facilitate evacuation of

    478 2025 CALIFORNIA PLUMBING CODE

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

    CURBLESS SHOWER RECEPTORS TCNA HANDBOOK

    shower water and splash water that is not contained in the shower area due to curbless design. Location of the high point of the floor is especially critical when secondary drain is not included outside the shower area.

    • Refer to appropriate wall method for applicable requirements based on type of backing used.

    • Slope mortar bed [1] ⁄ 4 " per foot toward drain and follow membrane and integrated bonding flange manufacturer’s instructions for connecting membrane to integrated bonding flange.

    Materials

  • CPC § 2025 High relevance — show source text

    Chapter 7 Sanitary Drainage.

    This chapter regulates the design and installation of sanitary drainage systems to ensure they will work as intended. Drainage piping should not be oversized nor undersized, and constructed of approved materials to guard against fouling, deposit of solids, clogging, and with cleanouts so arranged that the pipes may be readily cleaned. The purpose of the sanitary drainage system is to remove effluent discharged from plumbing fixtures and other equipment to an approved point of disposal, such as a public sanitary system or private sewage disposal system.

    The basics of a sanitary drainage system include public and private sewage disposal; selection of materials; installation of the building drain and sewer; joining methods for pipe and fittings; drainage fixture units for sizing the drainage system; sumps and ejectors; vent sizing and length of vents; and testing.

    Chapter 8 Indirect Wastes.

    Chapter 8 regulates indirect waste connections that are required for plumbing fixtures and plumbing appliances dealing with food preparation, dishwashing, potable liquids, and similar equipment. An indirect connection prevents sewage from backing up into a fixture or appliance, thus providing protection against potential health hazards. The waste pipe discharges through an air gap or air break into a waste receptor or standpipe. The protection in the form of an air gap is necessary when the contamination is a potential health hazard or cross connection with the potable water system. Where there is no possibility of contaminating the potable water (nonpotable discharge), the indirect waste pipe may connect in the form of an air break. This method is often preferred to prevent splashing. In addition, health care facilities and special wastes must be protected from contamination that may result from the connection to the drainage system. The waste must be treated to prevent any damage to the piping or sewage treatment process. Waste receptors are sized and designed to prevent splashing and allow for peak discharge conditions.

    Chapter 9 Vents.

    Chapter 9 regulates the material, design, and installation of vents. A vent system is a pipe or pipes installed in a drainage system that provide a flow of air to and from the system to ventilate it, provide a circulation of air to eliminate trap siphonage, and reduce back-pressure and vacuum surge. In addition, vents provide the rapid and silent flow of waste without exposing occupants of the building to any sewer gases. Proper installation of vents is crucial, as a telltale sign that there is a problem in the drain and vent system is related to the elevation of the horizontal portion of the venting. Venting is not limited to sanitary drainage systems. Venting methods are applicable to other drainage systems such as those for chemical waste, graywater waste, and clear water waste. Sizing the venting system is directly tied to the design of the drainage system. For example, the velocities in the drainage system and its peak flow rates affect the diameters in the venting system. Where the vertical distance between a fixture outlet and trap is excessive, velocities in the entire drainage system will be greater than those in the vent sizing table. All venting methods in this chapter are categorized as either dry vents or wet vents. Vent stacks, stack vents, branch vents, island vents, relief vents, and individual vents are dry vents. Wet vents (horizontal or vertical), circuit vents, combination drain and vents are versions of “wet venting” in which the vent is wetted by drainage flow.

    2025 CALIFORNIA PLUMBING CODE xv

  • CPC § 476 High relevance — show source text

    • For installations that may be exposed to staining, specify tile and grout suitable for exposure. Consult product manufacturers; see also “Product Selection Guides.”

    • For installations that may be exposed to mild chemical attack, specify epoxy grout and tile suitable for exposure. Consult product manufacturers; see also “Product Selection Guides.”

    Limitations

    • Facilitates construction of a curbless shower without adding floor height at restroom entryway, but does not inherently comply with Americans with Disabilities Act (ADA) Standards for Accessible Design. Follow ADA where ADA compliance is required or desired.

    • Refer to appropriate wall method for applicable limitations based on type of backing used—W201, W202E, W202I, W211, W221, W222, W231/W241, W243, W244C, W244E, W244F, W245, W246, and W247.

    Requirements

    • When glass tile is used, consult glass tile manufacturer for tile suitability over non-absorptive surface.

    • Bonded waterproof membrane must be continuous, including at changes in plane. Follow membrane manufacturer’s requirements for corners, seaming, and overlap.

    • Waterproof membrane inside shower area must extend to full height of tile assembly. Also, the floor and wall waterproofing must continue outside the immediate shower area one foot beyond the high point of the floor, but not beyond the tiled area. Additional waterproofing of floor and/or walls outside the shower area may be needed to effectively contain and evacuate shower water and splash water and to protect building materials. When additional waterproofing of floor and/or walls outside the shower area is desired or

    required, the building design professional must specify all areas to be waterproofed and indicate membrane termination points.

    • A secondary drain may be required outside the immediate shower area to facilitate evacuation of shower water and

    splash water that is not contained in the shower area due to curbless design. When required or desired, building design professional must specify type and location of secondary drain.

    • High point of the floor must be outside the shower area, i.e., beyond shower door or curtain, to facilitate evacuation of shower water and splash water that is not contained in the shower area due to curbless design. Location of the high point of the floor is especially critical when secondary drain is not included outside the shower area.

    • Surround drain with pea gravel or other weep protection to prevent mortar from blocking weep holes.

    476 2025 CALIFORNIA PLUMBING CODE

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

    CURBLESS SHOWER RECEPTORS TCNA HANDBOOK

    • Refer to appropriate wall method for applicable requirements based on type of backing used.

    • Slope mortar bed [1] ⁄ 4 " per foot toward drain and follow membrane manufacturer’s instructions for connecting membrane to drain.

    Materials

    • Multiple options exist for membranes, mortars, grouts, and other materials and must be clearly specified to be included. If not specifically indicated, optional materials are not included and mortar/grout choice defaults to minimum performance specification indicated. Con- sider each system component and intended use to deter- mine minimum requirements and to specify options.

    • Ceramic tile—ANSI A137.1.

    • Glass tile, when used—ANSI A137.2; see also “Glass Tile Selection and Installation Guide,” and consult tile manufacturer for environmental exposure classification recommendations. Not all glass tiles are suitable.

  • CPC § 7-3 High relevance — show source text

    702 Building Elements and Materials . . . . . . . . . . . . . . . . . 7-3

    703 Fire Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4

    704 Means of Egress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4

    705 Reroofing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4

    706 Structural. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5

    707 Reserved . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6

    708 Energy Conservation. . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6

    CHAPTER 8 ALTERATIONS—LEVEL 2 . . . . . . . . . . . . . . . . . .8-3

    801 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3

    802 Building Elements and Materials . . . . . . . . . . . . . . . . . 8-3

    803 Fire Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5

    804 Means of Egress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5

    805 Structural. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-9

    806 Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10

    807 Mechanical. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10

    808 Reserved . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10

    809 Energy Conservation. . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10

    CHAPTER 9 ALTERATIONS—LEVEL 3 . . . . . . . . . . . . . . . . . .9-3

    901 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3

  • CPC § 7-21 High relevance — show source text

    713 Shaft Enclosures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-21

    714 Penetrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-23

    715 Joints and Voids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-26

    716 Opening Protectives . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-27

    717 Ducts and Air Transfer Openings . . . . . . . . . . . . . . . . 7-34

    718 Concealed Spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-40

    719 Fire-Resistance Requirements for Plaster . . . . . . . . 7-42

    720 Thermal- and Sound-Insulating Materials . . . . . . . . 7-42

    721 Prescriptive Fire Resistance. . . . . . . . . . . . . . . . . . . . . 7-43

    722 Calculated Fire Resistance. . . . . . . . . . . . . . . . . . . . . . 7-66

    CHAPTER 7A [SFM] MATERIALS AND CONSTRUCTION

    METHODS FOR EXTERIOR WILDFIRE EXPOSURE . . . . . . . 7A-1

    CHAPTER 8 INTERIOR FINISHES. . . . . . . . . . . . . . . . . . . . . .8-1

    801 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3

    802 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3

    803 Wall and Ceiling Finishes . . . . . . . . . . . . . . . . . . . . . . . . 8-3

    804 Interior Floor Finish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6

    805 Combustible Materials in Types I and II Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7

    806 Decorative Materials and Trim . . . . . . . . . . . . . . . . . . . 8-7

    807 Insulation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8

    808 Acoustical Ceiling Systems . . . . . . . . . . . . . . . . . . . . . . 8-8

    CHAPTER 9 FIRE PROTECTION AND LIFE

  • CPC § 2025 High relevance — show source text

    The waste must be treated to prevent any damage to the piping or sewage treatment process. Waste receptors are sized and designed to prevent splashing and allow for peak discharge conditions.

    Chapter 9 Vents.

    Chapter 9 regulates the material, design, and installation of vents. A vent system is a pipe or pipes installed in a drainage system that provide a flow of air to and from the system to ventilate it, provide a circulation of air to eliminate trap siphonage, and reduce back-pressure and vacuum surge. In addition, vents provide the rapid and silent flow of waste without exposing occupants of the building to any sewer gases. Proper installation of vents is crucial, as a telltale sign that there is a problem in the drain and vent system is related to the elevation of the horizontal portion of the venting. Venting is not limited to sanitary drainage systems. Venting methods are applicable to other drainage systems such as those for chemical waste, graywater waste, and clear water waste. Sizing the venting system is directly tied to the design of the drainage system. For example, the velocities in the drainage system and its peak flow rates affect the diameters in the venting system. Where the vertical distance between a fixture outlet and trap is excessive, velocities in the entire drainage system will be greater than those in the vent sizing table. All venting methods in this chapter are categorized as either dry vents or wet vents. Vent stacks, stack vents, branch vents, island vents, relief vents, and individual vents are dry vents. Wet vents (horizontal or vertical), circuit vents, combination drain and vents are versions of “wet venting” in which the vent is wetted by drainage flow.

    2025 CALIFORNIA PLUMBING CODE xv

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

    FORMAT OF THE UNIFORM PLUMBING CODE

    Chapter 10 Traps and Interceptors.

    Chapter 10 regulates the material, design, and installation of traps, interceptors, and separators. Traps are required on drainage type plumbing fixtures and must be self-scouring without interior partitions. Interceptors, on the other hand, are designed to control what goes down a drain. Interceptors are used to keep harmful substances from entering the sanitary drainage system, such as grease, sand, oil and other materials. The retained materials need periodic removal to maintain efficiency and function of the separating device. The capacity of an interceptor is based on retention and flow rate. There are many types of interceptors that are used at beauty salons, hospitals, meat, fish or foul packaging, refineries, repair garages, gas stations, car washing facilities, various plants, factories, and processing sites. The designer of the building is responsible for locating interceptors with the expectation for the frequency of maintenance, ease of cleaning and floor space for equipment.

    Chapter 11 Storm Drainage.

    Chapter 11 regulates the removal of stormwater from roofs, yards, paved areas, and similar areas. The objective of storm drainage systems is to provide a conduit or channel through which runoff will be carried from a point of collection to a point of disposal; this protects the property and the public from the uncontrolled flow of runoff and ensures that drains and inlets are adequately sized to receive the volume of runoff that flows to the drains. For the purpose of system design, it’s necessary to specify the duration of a selected storm.

  • CPC § 6.4 Medium relevance — show source text

    6.4|Yes|Yes|No|No|No|No|Yes|Yes| |Spill control and
    neutralization|1207.6.2|Yesc|Yesc|Yesf|No|Yes|No|Yes|Yes| |Thermal
    runaway|1207.6.5|Yesd|Yes|Yese|Yese|No|Yes|Yese|Yes| |a. Not required for lead-acid and nickel-cadmium batteries at facilities under the exclusive control of communications utilities that comply with NFPA 76 and operate at less
    than 50 VAC and 60 VDC.
    b. Protection shall be provided unless documentation acceptable to the fire code official is provided in accordance with Section 104.2.2 that provides justification why the
    protection is not necessary based on the technology used.
    c. Applicable to vented-type (i.e., flooded) nickel-cadmium and lead-acid batteries.
    d. Not required for vented-type (i.e., flooded) batteries.
    e. The thermal runaway protection is permitted to be part of a battery management system that has been evaluated with the battery as part of the evaluation to UL 1973.
    f. Not required for batteries with jelled electrolyte.|a. Not required for lead-acid and nickel-cadmium batteries at facilities under the exclusive control of communications utilities that comply with NFPA 76 and operate at less
    than 50 VAC and 60 VDC.
    b. Protection shall be provided unless documentation acceptable to the fire code official is provided in accordance with Section 104.2.2 that provides justification why the
    protection is not necessary based on the technology used.
    c. Applicable to vented-type (i.e., flooded) nickel-cadmium and lead-acid batteries.
    d. Not required for vented-type (i.e., flooded) batteries.
    e. The thermal runaway protection is permitted to be part of a battery management system that has been evaluated with the battery as part of the evaluation to UL 1973.
    f. Not required for batteries with jelled electrolyte.|a. Not required for lead-acid and nickel-cadmium batteries at facilities under the exclusive control of communications utilities that comply with NFPA 76 and operate at less
    than 50 VAC and 60 VDC.
    b. Protection shall be provided unless documentation acceptable to the fire code official is provided in accordance with Section 104.2.2 that provides justification why the
    protection is not necessary based on the technology used.
    c. Applicable to vented-type (i.e., flooded) nickel-cadmium and lead-acid batteries.
    d. Not required for vented-type (i.e., flooded) batteries.
    e. The thermal runaway protection is permitted to be part of a battery management system that has been evaluated with the battery as part of the evaluation to UL 1973.
    f. Not required for batteries with jelled electrolyte.|a. Not required for lead-acid and nickel-cadmium batteries at facilities under the exclusive control of communications utilities that comply with NFPA 76 and operate at less
    than 50 VAC and 60 VDC.
    b. Protection shall be provided unless documentation acceptable to the fire code official is provided in accordance with Section 104.2.2 that provides justification why the
    protection is not necessary based on the technology used.
    c. Applicable to vented-type (i.e., flooded) nickel-cadmium and lead-acid batteries.
    d. Not required for vented-type (i.e., flooded) batteries.
    e.

  • CPC § 803.0 Medium relevance — show source text

    803.0 Indirect Waste Piping.

    803.1 Materials. Pipe, tube, and fittings conveying indirect waste shall be of such materials and design as to perform their intended function to the satisfaction of the Authority Having Jurisdiction.

    803.2 Copper and Copper Alloys. Joints and connections in copper and copper alloy pipe and tube shall be installed in accordance with Section 705.3.

    803.3 Pipe Size and Length. Except as hereinafter provided, the size of indirect waste piping shall be in accordance with other sections of this code applicable to drainage and vent piping. No vent from indirect waste piping shall combine with a sewer-connected vent. Vents from indirect waste piping shall extend separately to the outside air. Indirect waste pipes exceeding 5 feet (1524 mm), but less than 15 feet (4572 mm) in length shall be directly trapped, but such traps need not be vented.

    Indirect waste pipes less than 15 feet (4572 mm) in length shall be not less than the diameter of the drain outlet or

    2025 CALIFORNIA PLUMBING CODE 181

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

    INDIRECT WASTES

    tailpiece of the fixture, appliance, or equipment served, and in no case less than [1] ⁄ 2 of an inch (15 mm). Angles and changes of direction in such indirect waste pipes shall be provided with cleanouts to permit flushing and cleaning.

    804.0 Indirect Waste Receptors.

    804.1 Standpipe Receptors. Plumbing fixtures or other receptors receiving the discharge of indirect waste pipes shall be approved for the use proposed and shall be of such shape and capacity as to prevent splashing or flooding and shall be located where they are readily accessible for inspection and cleaning. No standpipe receptor for a clothes washer shall extend more than 30 inches (762 mm), or not less than 18 inches (457 mm) above its trap weir. No trap for a clothes washer standpipe receptor shall be installed below the floor, but shall be roughed in not less than 6 inches (152 mm) and not more than 18 inches (457 mm) above the floor. No indirect waste receptor shall be installed in a toilet room, closet, cupboard, or storeroom, or in a portion of a building not in general use by the occupants thereof; except standpipes for clothes washers shall be permitted to be installed in toilet and bathroom areas where the clothes washer is installed in the

    same room.

    805.0 Pressure Drainage Connections. 805.1 General. Indirect waste connections shall be provided for drains, overflows, or relief vents from the water supply system, and no piping or equipment carrying wastes or producing wastes or other discharges under pressure shall be directly connected to a part of the drainage system.

    The preceding shall not apply to an approved sump pump or to an approved pressure-wasting plumbing fixture or device where the Authority Having Jurisdiction has been satisfied that the drainage system is adequately sized to accommodate the anticipated discharge thereof.

    806.0 Sterile Equipment.

    806.1 General. Appliances, devices, or apparatus such as stills, sterilizers, and similar equipment requiring water and waste and used for sterile materials shall be drained through an air gap.

    807.0 Appliances.

  • CPC § 803.13 Medium relevance — show source text

    Interior finishes Table 803.13, 804 Live load Table 1607.1 Means of egress Corridors 1020.3

    Stairway, exit access 1019

    Travel distance 407, 1006.3, 1017.2,

    1006.2.1

    Mixed occupancies 508.3, 508.4 Occupancy exceptions 303.1.1, 303.1.2, 308.5.1, 308.5.4, 310.4.1 Plumbing fixtures Chapter 29 Risk category Table 1604.5 Standby, emergency power 2702.2 Insulation

    Concealed 720.2

    Duct insulation 720.1

    Exposed 720.3 Fiberboard 720.1, Table 1508.2, 2303.1.6.2, 2303.1.6.3 Foam plastic (see Foam Plastics) 720.1

    Loose fill 720.4, 720.6 Pipe insulation 720.1, 720.7 Reflective plastic core 2614 Roof 720.5, 1508 Sound 720, 807, 1206 Thermal 720, 807, 1508 Interior Environment Lighting 1204 Rodentproofing Appendix F Sound transmission 1206

    Space dimensions 1208 Temperature control 1203 Ventilation 409.3, 414.3, 415.9.1.7,

    1202.5

    Yards or courts 1205.2, 1205.3 Interior Finishes Chapter 8 Acoustical ceiling systems 807, 808 Application 803.13, 804.4 Atriums 404.8 Children’s play structures 424 Covered and open mall buildings 402.6

    Decorative materials 419, 802.3, 806 Floor finish 804, 805 Foam plastic insulation 2603.3, 2603.4 Foam plastic trim 806.6.1, 2604.2 Insulation 807 Light-transmitting plastics 2606 Signs 402.6.4, 2611 Site-fabricated stretch systems 803.10 Trim 806.6, 806.7 Wall and ceiling finishes 803 Wet location 1210 Intermodal Shipping Container 3114 Interpretation, Code 104.1

    Jails [see Institutional (see Group I-3)] 308.5, 408 Joint Gypsum board 2508.5 Lumber sheathing 2308.11.10 Waterproofing 1805.3.3 Joints, Fire-resistant Systems 715 Special inspection 1705.18

    Kiosks 402.6.2

    Kitchens 303.3, 306.2 Accessibility 1133A, 11B-212 Dimensions 1209 Means of egress 1016.2 Occupant load Table 1004.5 Sinks Chapter 29

    INDEX-12 2025 CALIFORNIA BUILDING CODE

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

    INDEX

    Marquees 3106, H113 Construction 3106.5

  • CPC § 1020.2 Medium relevance — show source text

    Corridors 1020.2

    Doors 1010.2.13, 1010.2.11, 1010.2.9, 1010.2.7, 1010.2.12.1 Lighting 1008.2, 1008.2.4 Stairway, exterior exit 1027.2 Stairways, exit access 1019 Travel distance 1006.3, 1017.2 Sprinkler protection 903.2.6, 903.3.2 Integrated Testing (Fire Protection and Life Safety Systems) 202, 901.6.2 Interconnection Fire-extinguishing systems with cooking appliances 904.14.2 Smoke alarms 907.2.11.5, 1103.8.2 Standpipe risers 905.4.2 Interior Finish Chapter 8 Defined 202

    Interior Floor-Wall Base 804.4

    Defined 202 Interior Wall and Ceiling Finish 803, 804 Defined 202 Interior Wall and Ceiling Finish and Trim 803, 804 Intumescent Fire-Resistant Materials 708 Investigations, Fire 104.10 Irritant

    Defined 202

    Gases 5004.7.1, 5307.1

    Iso-Butane (see Liquefied Petroleum Gas)

    Jurisdiction

    Defined 202

    Kettles [see Organic Coating or Asphalt (Tar) Kettles] Key Boxes 202, 506 Maintenance 506.2

    Nonstandard fire service elevator keys 506.1.2 Required 506.1 Keys, Fire Service Elevator 604.6

    Laboratory Suite 202 Ladders 1104.16.6, 5704.2.8.15 Boiler, incinerator and furnace rooms

    1006.2.2.1

    Construction 1011.15, 1011.16, 1014.2, 1014.7, 1015.3, 1015.4 Emergency escape window wells 1031.5.2

    Group I-3 1011.15, 1011.16 Refrigeration machinery rooms 1006.2.2.2

    Ship’s ladders 1011.15 Landing Ramps 1012.6, 1012.10 Stairs and stairways 1010.1.4, 1010.1.5, 1011.6, 1025.2.4 Landscaped Roofs (see also Rooftop Gardens) 317, 504.3, 905.3.7 Dead foliage 317.2.2 Irrigation 317.2.1 Maintenance equipment 317.4 Maintenance plan 317.3 Laundry Carts 318.1 Lead-Acid Battery System, Stationary (see Battery Systems, Stationary Storage) Lead-Acid Battery System, Valve-Regulated (see Battery Systems, Stationary Storage) Leaks Compressed gases 5303.12 Cryogenic fluids 5503.9 Explosive materials 5604.10 Flammable and combustible

  • CPC § 8-8 Medium relevance — show source text

    CHAPTER 8-8 ARCHAIC MATERIALS AND METHODS OF

    CONSTRUCTION . . . . . . . . . . . . . . . . . . . . . . . 15

    Section

    8-801 Purpose, Intent and Scope . . . . . . . . . . . . . . . . . . . . . . 15 8-802 General Engineering Approaches. . . . . . . . . . . . . . . . . 15 8-803 Nonstructural Archaic Materials. . . . . . . . . . . . . . . . . . 15

    8-804 Allowable Conditions for Specific Materials . . . . . . . 15 8-805 Masonry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 8-806 Adobe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

    8-807 Wood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

    8-808 Concrete . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

    8-809 Steel and Iron . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

    8-810 Hollow Clay Tile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

    8-811 Veneers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

    8-812 Glass and Glazing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

    CHAPTER 8-9 MECHANICAL, PLUMBING AND ELECTRICAL REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . 19

    Section

    8-901 Purpose, Intent and Scope . . . . . . . . . . . . . . . . . . . . . . 19 8-902 Mechanical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

    8-903 Plumbing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 8-904 Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

    CHAPTER 8-10 QUALIFIED HISTORICAL DISTRICTS,

    SITES AND OPEN SPACES . . . . . . . . . . . . . . . 23

    Section

  • CPC § 506.6 Medium relevance — show source text

    Except for ducts used to convey noncorrosive vapors with no particulate, accessible cleanouts shall be provided at 10 foot (3048 mm) intervals and at changes in direction. Access openings shall also be provided for access to sprinklers and other equipment within the duct that require servicing.

    506.6 Explosion Venting. Ducts conveying explosive dusts shall have explosion vents, openings protected by anti-flashback swing valves, or rupture diaphragms. Openings to relieve explosive forces shall be located outside the building. Where relief devices cannot provide sufficient pressure relief, ductwork shall be designed to withstand an internal pressure of not less than 100 pounds-force per square inch (psi) (689 kPa).

    Where a room or building contains a dust explosion hazard that is external to protected equipment, as defined in NFPA 654, such areas shall be provided with deflagration venting to a safe outside location.

    Systems exhausting explosive mixtures shall be protected by an approved explosion relief system in accordance with NFPA 69.

    506.7 Supports. Supports shall be of noncombustible materials, and the spacing shall not exceed 12 feet (3658 mm) for 8 inch (203 mm) ducts and 20 feet (6096 mm) for larger ducts.

    506.8 Fire Protection. Sprinklers or other fire-protection devices shall be installed within ducts having a cross-sectional dimension exceeding 10 inches (254 mm) where the duct conveys flammable vapors or fumes. Sprinklers shall be installed at 12 foot (3658 mm) intervals in horizontal ducts and at changes in direction. In vertical runs, sprinklers shall be installed at the top and at alternate floor levels.

    506.8.1 Loads. Duct supports shall be designed to carry the weight of the duct half filled with material. Where sprinkler protection is provided or cleaning of the duct will be performed, the hanger’s design shall include the weight of any expected liquid accumulation. Duct supports shall be designed to prevent placing loads on connected equipment. [NFPA 91:4.6.1 – 4.6.3]

    506.8.2 Corrosion. Hangers and supports exposed to corrosive atmospheres shall be resistant to the corrosive atmospheres. [NFPA 91:4.6.4]

    506.8.3 Vibration and Stress. To avoid vibration and stress on the duct, hangers and supports shall be securely fastened to the building or structure. [NFPA 91:4.6.5]

    506.8.4 Expansion and Contraction. Hangers and supports shall be designed to allow for expansion and contraction. [NFPA 91:4.6.6]

    506.9 Protection from Physical Damage. Ducts and exhaust equipment installed in locations where they are subject to physical damage shall be protected by guards.

    506.10 Duct Clearances. Unless the conditions stipulated in Section 506.10.1 or Section 506.10.2 exist, all duct systems and system components shall have a clearance of at least 6 inches (152 mm) from stored combustible materials, and not less than [1] ⁄ 2 of an inch (13 mm) clearance from combustible construction. [NFPA 91:4.7.1]

Frequently asked questions

What counts as an “approved” receptor?

“Approved” means accepted by the Authority Having Jurisdiction or otherwise demonstrated suitable for the proposed use (manufacturer data, listings). § 804.1 requires approval but does not prescribe specific test numbers.

Must every indirect‑waste trap be vented?

No. For indirect waste pipes > 5 ft and < 15 ft, a direct trap is required but need not be vented per § 803.3.

How large must a receptor be to prevent splashing?

The CPC requires receptors to be “of such shape and capacity as to prevent splashing,” but does not give a numeric volume or shape in § 804.1 — use an approved product or get AHJ guidance.

Can I put an indirect-waste receptor inside a closet?

Generally no — § 804.1 prohibits receptors in toilet rooms, closets, cupboards, storerooms, or portions not in general use. Exception exists only for clothes‑washer standpipes in the same bathroom where the washer is installed.

Are cleanouts always required?

Cleanouts are required at angles and changes of direction in indirect waste piping to permit flushing and cleaning (per § 803.3).

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Related in the CPC

Where may indirect waste receptors be installed and when is AHJ approval required?

How must standpipe receptors be sized, located and installed (clothes washers etc.)?

Indirect waste receptors, standpipes, and receptor installation rules

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