CPC · California Plumbing Code

Indirect waste receptors, standpipes, and receptor installation rules

Chapter 8 of the CPC governs indirect waste piping and receptors—requiring air gaps/air breaks, specifying standpipe/receptor placement and sizing, and prescribing appliance‑specific connections.

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Last reviewed: July 6, 2026

Overview

This area of the California Plumbing Code (CPC) is Chapter 8 (Indirect Wastes) and governs the design, materials, and installation of indirect waste piping, receptors (open or trapped), and standpipes used to receive discharges from equipment and fixtures where a direct connection would create a cross‑connection or sanitary hazard. See §801.0 for scope and the air‑gap/air‑break requirement in §801.2, which establish the basic protection principle for indirect connections.

Key receptor and standpipe rules include required receptor shape/capacity and accessibility, limits on clothes‑washer standpipe heights and trap locations, and restrictions on where receptors may be located (for example, prohibiting receptors in toilet rooms except where a clothes washer is installed in the same room). Those specifics are set out in §804.1.

Related requirements you’ll commonly need to coordinate with are indirect waste pipe sizing and maximum developed lengths (including trap and venting requirements) in §803.3, and pressure drainage/indirect connections for pressurized devices in §805.1. Appliance‑specific rules (for example, dishwasher air‑gap fittings) are in Chapter 8 as well (see §807.3 for domestic dishwashing machines).

In this section

Code references

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

CPC § 803.0 High 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

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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 § 901.0 High relevance — show source text
APPENDIX Q

Q 901.0 Sanitary Drainage and Indirect Wastes. Q 901.1 General. Sanitary drainage shall be in accordance with Chapter 7. Indirect wastes shall be in accordance with Chapter 8. The drainage system shall be compatible with the discharge liquid waste.

Q 901.2 Hazardous Materials. Hazardous materials shall not be discharged into the sanitary sewer, storm drain, or on the ground. Q 901.3 Agricultural Water Waste. Agricultural water shall be discharged in accordance with the local, state, and federal regulations as approved by the Authority Having Jurisdiction. Where agricultural water discharges to the outdoors, and is not connected to the sanitary sewer, the piping shall be installed as to restrict rodents or vermin from entering the building. Q 901.4 Floor Drains, Floor Sinks, and Receptors. Wastewater shall discharge into an approved receptor. Receptors shall be compatible with the wastewater and installed in accordance with this code.

Q 901.4.1 Plant Storage Areas. Where drains are provided in spaces where plants are stored, such drains shall be installed with indirect waste piping. Each indirect waste pipe from plant storage areas shall be separately piped to the indirect waste receptor and shall not combine with other indirect waste pipes.

Q 1001.0 Facilities.

Q 1001.1 Toilet Facilities. Toilet facilities shall be provided in accordance with the occupancy type.

Q 1001.2 Location. Toilet facilities shall be located in such a manner to prevent contamination of plants during harvesting, holding, manufacturing/processing, and packing.

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CALIFORNIA PLUMBING CODE – MATRIX ADOPTION TABLE

APPENDIX R - TINY HOUSES

(Matrix Adoption Tables are non-regulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)
CPC § 801.7 High relevance — show source text
801.7 Drip or Drainage Outlets . . . . . . . .181

802.0 Approvals . . . . . . . . . . . . . . . . . . .181

802.1 General . . . . . . . . . . . . . . . . . . . . .181

803.0 Indirect Waste Piping . . . . . . . . . .181

803.1 Materials . . . . . . . . . . . . . . . . . . . .181

803.2 Copper and Copper Alloys . . . . . .181

803.3 Pipe Size and Length . . . . . . . . . .181

804.0 Indirect Waste Receptors . . . . . . .182

804.1 Standpipe Receptors . . . . . . . . . .182

805.0 Pressure Drainage Connections . . . . . . . . . . . . . . . . .182

805.1 General . . . . . . . . . . . . . . . . . . . . .182

806.0 Sterile Equipment . . . . . . . . . . . . .182

806.1 General . . . . . . . . . . . . . . . . . . . . .182

807.0 Appliances . . . . . . . . . . . . . . . . . .182

807.1 Non-Classed Apparatus . . . . . . . .182

807.2 Undiluted Condensate Waste . . . .182

807.3 Domestic Dishwashing Machine . . . . . . . . . . . . . . . . . . . .182

808.0 Cooling Water . . . . . . . . . . . . . . . .182

808.1 General . . . . . . . . . . . . . . . . . . . . .182

809.0 Drinking Fountains . . . . . . . . . . . .182

809.1 General . . . . . . . . . . . . . . . . . . . . .182

810.0 Steam and Hot Water Drainage Condensers and Sumps . . . . . . . .182

810.1 High-Temperature Discharge . . . .182

Table 810.1 Pipe Connections in Blowoff Condensers and Sumps . . . . . . . .183

810.2 Sumps, Condensers, and Intercepting Tanks . . . . . . . . . . . .183

810.3 Cleaning . . . . . . . . . . . . . . . . . . . .183

810.4 Strainers . . . . . . . . . . . . . . . . . . . .183

811.0 Chemical Wastes . . . . . . . . . . . . .183

811.1 Pretreatment . . . . . . . . . . . . . . . . .183

811.2 Waste and Vent Pipes . . . . . . . . .183

811.3 Joining Materials . . . . . . . . . . . . . .183

811.4 Access . . . . . . . . . . . . . . . . . . . . .183

811.5 Permanent Record . . . . . . . . . . . .183

811.6 Chemical Vent . . . . . . . . . . . . . . .183
CPC § 601.0 High relevance — show source text
Q 601.0 Water Supply. Q 601.1 General. Indoor horticulture water distribution systems shall be supplied with potable water in accordance with Chapter 6. Q 601.2 Materials. Pipe, tube, and fitting materials in contact with potable water, drinking water, or both shall be in accordance with Section 604.0.

Q 601.3 Protection. Potable water piping used for irrigation purposes shall be equipped with an approved backflow prevention device or assembly in accordance with Table 603.2.

Q 601.4 Alternate Water Supply. Where permitted, agricultural water may be used or alternate water sources in accordance with Appendix K.

Q 701.0 Storage Tanks. Q 701.1 Construction. Where storage tanks are used, they shall be approved by the Authority Having Jurisdiction. Potable water storage tanks shall comply with Section 607.0. Rainwater catchment storage tanks shall comply with Appendix K or in accordance with the Authority Having Jurisdiction.

Q 801.0 Fertigation and Irrigation Equipment. Q 801.1 Installation. Nutrient tanks and irrigation equipment shall be installed in accordance with the manufacturer’s instructions. When connected to the potable water supply, tanks and irrigation equipment shall be located downstream of water storage tank and be protected by an approved backflow device or method in accordance with Table 603.2

Q 801.2 Materials and Construction. The piping, components, and devices shall be compatible with the additives or nutrients used. Above grade storage tanks shall be of an opaque material, approved for aboveground use in direct sunlight, or shall be shielded from direct sunlight.

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APPENDIX Q

Q 901.0 Sanitary Drainage and Indirect Wastes. Q 901.1 General. Sanitary drainage shall be in accordance with Chapter 7. Indirect wastes shall be in accordance with Chapter 8. The drainage system shall be compatible with the discharge liquid waste.

Q 901.2 Hazardous Materials. Hazardous materials shall not be discharged into the sanitary sewer, storm drain, or on the ground. Q 901.3 Agricultural Water Waste. Agricultural water shall be discharged in accordance with the local, state, and federal regulations as approved by the Authority Having Jurisdiction. Where agricultural water discharges to the outdoors, and is not connected to the sanitary sewer, the piping shall be installed as to restrict rodents or vermin from entering the building. Q 901.4 Floor Drains, Floor Sinks, and Receptors. Wastewater shall discharge into an approved receptor. Receptors shall be compatible with the wastewater and installed in accordance with this code.

Q 901.4.1 Plant Storage Areas. Where drains are provided in spaces where plants are stored, such drains shall be installed with indirect waste piping. Each indirect waste pipe from plant storage areas shall be separately piped to the indirect waste receptor and shall not combine with other indirect waste pipes.

Q 1001.0 Facilities.

Q 1001.1 Toilet Facilities. Toilet facilities shall be provided in accordance with the occupancy type.

Q 1001.2 Location. Toilet facilities shall be located in such a manner to prevent contamination of plants during harvesting, holding, manufacturing/processing, and packing.
CPC § 805.0 High relevance — show source text
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.

807.1 Non-Classed Apparatus. Commercial dishwashing machines, silverware washing machines, and other appliances, devices, equipment, or other apparatus not regularly classed as plumbing fixtures, which are equipped with pumps, drips, or drainage outlets, shall be permitted to be drained by indirect waste pipes discharging through an air break into an approved type of open receptor.

807.2 Undiluted Condensate Waste. Where undiluted condensate waste from a fuel-burning condensing appliance is discharged into the drainage system, the material in the drainage system shall be cast-iron, galvanized iron, plastic, or other materials approved for this use.

Exceptions:

(1) Where the above condensate is discharged to an exposed fixture tailpiece and trap, such tailpiece and trap shall be permitted to be a copper alloy.

(2) Materials approved in Section 701.0 shall be permitted to be used where data is provided that the condensate waste is adequately diluted.

807.3 Domestic Dishwashing Machine. No domestic dishwashing machine shall be directly connected to a drainage system or food waste disposer without the use of an approved dishwasher air gap fitting on the discharge side of the dishwashing machine. Listed dishwasher air gap fittings shall be installed with the flood-level (FL) marking at or above the flood level of the sink or drainboard, whichever is higher.

808.0 Cooling Water.

808.1 General. Where permitted by the Authority Having Jurisdiction, clean running water used exclusively as a cooling medium in an appliance, device, or apparatus shall be permitted to discharge into the drainage system through the inlet side of a fixture trap in the event that a suitable fixture is not available to receive such discharge. Such trap connection shall be by means of a pipe connected to the inlet side of an approved fixture trap, the upper end terminating in a funnelshaped receptacle set adjacent, and not less than 6 inches (152 mm) above the overflow rim of the fixture.
CPC § 801.3.1 High relevance — show source text
801.3.1 Size of Indirect Waste Pipes. Except for refrigeration coils and ice-making machines, the size of the indirect waste pipe shall be not smaller than the drain on the unit, but shall be not smaller than 1 inch (25 mm), and the maximum developed length shall not exceed 15 feet (4572 mm). Indirect waste pipe for ice-making machines shall be not less than the drain on the unit and in no case less than [3] ⁄ 4 of an inch (20 mm). 801.3.2 Walk-In Coolers. For walk-in coolers, floor drains shall be permitted to be connected to a separate drainage line discharging into an outside receptor. The flood-level rim of the receptor shall be not less than 6 inches (152 mm) lower than the lowest floor drain. Such floor drains shall be trapped and individually vented. Cleanouts shall be provided at 90 degree (1.57 rad) turns and shall be accessibly located. Such waste shall discharge through an air gap or air break into a trapped and vented receptor, except that a full-size air gap is required where the indirect waste pipe is under vacuum. 801.3.3 Food-Handling Fixtures. Food-preparation sinks, steam kettles, potato peelers, ice cream dipper wells, and similar equipment shall be indirectly connected to the drainage system by means of an air gap. Bins, sinks, and other equipment having drainage connections and used for the storage of unpackaged ice used for human ingestion, or used in direct contact with ready-to-eat food, shall be indirectly connected to the drainage system by means of an air gap. Each indirect waste pipe from foodhandling fixtures or equipment shall be separately piped to the indirect waste receptor and shall not combine with other indirect waste pipes. The piping from the equipment to the receptor shall be not less than the drain on the unit and in no case less than [1] ⁄ 2 of an inch (15 mm).

801.4 Bar and Fountain Sink Traps. Where the sink in a bar, soda fountain, or counter is so located that the trap serving the sink cannot be vented, the sink drain shall discharge through an air gap or air break (see Section 801.3.3) into an approved receptor that is vented. The developed length from the fixture outlet to the receptor shall not exceed 5 feet (1524 mm). 801.5 Connections from Water Distribution System. Indirect waste connections shall be provided for drains, overflows, or relief pipes from potable water pressure tanks, water heaters, boilers, and similar equipment that is connected to the potable water distribution system. Such indirect waste connections shall be made using a water-distribution air gap constructed in accordance with Table 603.3.1.

801.6 Sterilizers. Lines, devices, or apparatus such as stills, sterilizers, and similar equipment requiring waste connections and used for sterile materials shall be indirectly connected using an air gap. Each such indirect waste pipe shall be separately piped to the receptor and shall not exceed 15 feet (4572 mm). Such receptors shall be located in the same room. 801.7 Drip or Drainage Outlets. Appliances, devices, or apparatus not regularly classified as plumbing fixtures, but which have a drip or drainage outlets, shall be permitted to be drained by indirect waste pipes discharging into an open receptor through either an air gap or air break (see Section 801.3.1).
CPC § 801.4 High relevance — show source text
The piping from the equipment to the receptor shall be not less than the drain on the unit and in no case less than [1] ⁄ 2 of an inch (15 mm).

801.4 Bar and Fountain Sink Traps. Where the sink in a bar, soda fountain, or counter is so located that the trap serving the sink cannot be vented, the sink drain shall discharge through an air gap or air break (see Section 801.3.3) into an approved receptor that is vented. The developed length from the fixture outlet to the receptor shall not exceed 5 feet (1524 mm). 801.5 Connections from Water Distribution System. Indirect waste connections shall be provided for drains, overflows, or relief pipes from potable water pressure tanks, water heaters, boilers, and similar equipment that is connected to the potable water distribution system. Such indirect waste connections shall be made using a water-distribution air gap constructed in accordance with Table 603.3.1.

801.6 Sterilizers. Lines, devices, or apparatus such as stills, sterilizers, and similar equipment requiring waste connections and used for sterile materials shall be indirectly connected using an air gap. Each such indirect waste pipe shall be separately piped to the receptor and shall not exceed 15 feet (4572 mm). Such receptors shall be located in the same room. 801.7 Drip or Drainage Outlets. Appliances, devices, or apparatus not regularly classified as plumbing fixtures, but which have a drip or drainage outlets, shall be permitted to be drained by indirect waste pipes discharging into an open receptor through either an air gap or air break (see Section 801.3.1).

802.0 Approvals. 802.1 General. No plumbing fixtures served by indirect waste pipes or receiving discharge therefrom shall be installed until first approved by the Authority Having Jurisdiction.

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

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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.
CPC § 1.11.0. High relevance — show source text
This state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.0.

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CHAPTER 8

INDIRECT WASTES

801.0 General.

801.1 Applicability. This chapter shall govern the materials, design, and installation of indirect waste piping, receptors, and connections; and provisions for discharge and disposal of condensate wastes, chemical wastes, industrial wastes, and clear water wastes.

801.2 Air Gap or Air Break Required. Indirect waste piping shall discharge into the building drainage system through an air gap or air break as set forth in this code. Where a drainage air gap is required by this code, the minimum vertical distance as measured from the lowest point of the indirect waste pipe or the fixture outlet to the flood-level rim of the receptor shall be not less than 1 inch (25.4 mm). 801.3 Food and Beverage Handling Establishments. Establishments engaged in the storage, preparation, selling, serving, processing, or other handling of food and beverage involving the following equipment that requires drainage shall provide indirect waste piping for refrigerators, refrigeration coils, freezers, walk-in coolers, iceboxes, ice-making machines, steam tables, egg boilers, coffee urns and brewers, hot-and-cold drink dispensers, and similar equipment. 801.3.1 Size of Indirect Waste Pipes. Except for refrigeration coils and ice-making machines, the size of the indirect waste pipe shall be not smaller than the drain on the unit, but shall be not smaller than 1 inch (25 mm), and the maximum developed length shall not exceed 15 feet (4572 mm). Indirect waste pipe for ice-making machines shall be not less than the drain on the unit and in no case less than [3] ⁄ 4 of an inch (20 mm). 801.3.2 Walk-In Coolers. For walk-in coolers, floor drains shall be permitted to be connected to a separate drainage line discharging into an outside receptor. The flood-level rim of the receptor shall be not less than 6 inches (152 mm) lower than the lowest floor drain. Such floor drains shall be trapped and individually vented. Cleanouts shall be provided at 90 degree (1.57 rad) turns and shall be accessibly located. Such waste shall discharge through an air gap or air break into a trapped and vented receptor, except that a full-size air gap is required where the indirect waste pipe is under vacuum. 801.3.3 Food-Handling Fixtures. Food-preparation sinks, steam kettles, potato peelers, ice cream dipper wells, and similar equipment shall be indirectly connected to the drainage system by means of an air gap.
CPC § 722.3 High relevance — show source text
722.3 Filling . . . . . . . . . . . . . . . . . . . . . .178

722.4 Ownership . . . . . . . . . . . . . . . . . .178

722.5 Disposal Facilities . . . . . . . . . . . . .178

723.0 Building Sewer Test . . . . . . . . . . .178

723.1 General . . . . . . . . . . . . . . . . . . . . .178

724.0 Meat and Poultry Processing Plant Drainage . . . . . . . . . . . . . . .178

725.0 Collection Center and

Facilities Drainage . . . . . . . . . . . .178

726.0 Drainage and Plumbing, General . . . . . . . . . . . . . . . . . . . . .178

727.0 Emergency Sanitary Drainage . . .178

CHAPTER 8 INDIRECT WASTES . . . . . . . . . .179

801.0 General . . . . . . . . . . . . . . . . . . . . .181

801.1 Applicability . . . . . . . . . . . . . . . . . .181

801.2 Air Gap or Air Break Required . . .181

801.3 Food and Beverage Handling Establishments . . . . . . .181

801.4 Bar and Fountain Sink Traps . . . .181

801.5 Connections from Water Distribution System . . . . . . . . . . . .181

801.6 Sterilizers . . . . . . . . . . . . . . . . . . .181

801.7 Drip or Drainage Outlets . . . . . . . .181

802.0 Approvals . . . . . . . . . . . . . . . . . . .181

802.1 General . . . . . . . . . . . . . . . . . . . . .181

803.0 Indirect Waste Piping . . . . . . . . . .181

803.1 Materials . . . . . . . . . . . . . . . . . . . .181

803.2 Copper and Copper Alloys . . . . . .181

803.3 Pipe Size and Length . . . . . . . . . .181

804.0 Indirect Waste Receptors . . . . . . .182

804.1 Standpipe Receptors . . . . . . . . . .182

805.0 Pressure Drainage Connections . . . . . . . . . . . . . . . . .182

805.1 General . . . . . . . . . . . . . . . . . . . . .182

806.0 Sterile Equipment . . . . . . . . . . . . .182

806.1 General . . . . . . . . . . . . . . . . . . . . .182

807.0 Appliances . . . . . . . . . . . . . . . . . .182

807.1 Non-Classed Apparatus . . . . . . . .182

807.2 Undiluted Condensate Waste . . . .182

807.3 Domestic Dishwashing Machine . . . . . . . . . . . . . . . . . . . .182
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.

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CPC § 1.3.4.1 Medium relevance — show source text
(1) Category 1 spaces

(2) Category 2 spaces

(3) Category 3 spaces

(4) Category 4 spaces [NFPA 99:1.3.4.1]

1302.3 Anesthesia. It shall be the responsibility of the health care facility’s governing body to designate anesthetizing locations. [NFPA 99:1.3.4.2]

1302.4 Wet Procedure Locations. It shall be the responsibility of the health care facility’s governing body to designate wet procedure locations. [NFPA 99:1.3.4.3]

1303.0 Health Care Facilities.

1303.1 Drinking Fountain Control Valves. Drinking fountain control valves shall be flush-mounted or fully recessed where installed in corridors or other areas where patients are transported on a gurney, bed, or wheelchair.

1303.2 Psychiatric Patient Rooms. Piping and drain traps in psychiatric patient rooms shall be concealed. Fixtures and fittings shall be resistant to vandalism.

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HEALTH CARE FACILITIES AND MEDICAL GAS AND MEDICAL VACUUM SYSTEMS

1303.3 Locations for Ice Storage. Ice makers or ice storage containers shall be located in nursing stations or similarly supervised areas to minimize potential contamination.

1303.4 Sterilizers and Bedpan Steamers. Sterilizers and bedpan steamers shall be installed in accordance with the manufacturer’s installation instructions and comply with Section 1303.4.1 and Section 1303.4.2.

1303.4.1 Drainage Connections. Sterilizers and bedpan steamers shall be connected to the sanitary drainage system through an air gap in accordance with Section 801.2. The size of indirect waste piping shall be not less than the size of the drain connection on the fixture. Each such indirect waste pipe shall not exceed 15 feet (4572 mm) in length and shall be separately piped to a receptor. Such receptors shall be located in the same room as the equipment served. Except for bedpan steamers, such indirect waste pipes shall not require traps. A trap having a seal of not less than 3 inches (76 mm) shall be provided in the indirect waste pipe for a bedpan

steamer.

1303.4.2 Vapor Vents and Stacks. Where a sterilizer or bedpan steamer has provision for a vapor vent and such a vent is required by the manufacturer, the vent shall be extended to the outdoors above the roof. Sterilizer and bedpan steamer vapor vents shall be installed in accordance with the manufacturer’s installation instructions and shall not be connected to a drainage system vent.

1303.5 Aspirators. Provisions for aspirators or other watersupplied suction devices shall be installed with the specific approval of the Authority Having Jurisdiction. Where aspirators are used for removing body fluids, they shall include a collection container to collect liquids and solid particles. Aspirators shall indirectly discharge to the sanitary drainage system through an air gap in accordance with Section 806.1. The potable water supply to an aspirator shall be protected by a vacuum breaker or equivalent backflow protection device in accordance with Section 603.5.9.

1303.6 Drains. Drains shall be installed on dryers, aftercoolers, separators, and receivers.

CPC § 901.4.1 Medium relevance — show source text

Q 901.4.1 Plant Storage Areas. Where drains are provided in spaces where plants are stored, such drains shall be installed with indirect waste piping. Each indirect waste pipe from plant storage areas shall be separately piped to the indirect waste receptor and shall not combine with other indirect waste pipes.

Q 1001.0 Facilities.

Q 1001.1 Toilet Facilities. Toilet facilities shall be provided in accordance with the occupancy type.

Q 1001.2 Location. Toilet facilities shall be located in such a manner to prevent contamination of plants during harvesting, holding, manufacturing/processing, and packing.

542 2025 CALIFORNIA PLUMBING CODE

CALIFORNIA PLUMBING CODE – MATRIX ADOPTION TABLE

APPENDIX R - TINY HOUSES

(Matrix Adoption Tables are non-regulatory, 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	Col10	OSHPD	Col12	Col13	Col14	Col15	Col16	Col17	BSCC	DPH	AGR	DWR	CEC	CA	SL	SLC
Adopting Agency	BSC	BSC- CG	SFM	1	2	1-AC	AC	SS	SS/CC	1	1R	2	3	4	5	6	6	6	6	6	6	6	6	6
Adopt Entire Chapter			X
Adopt Entire Chapter as amended (amended sections listed below)
Adopt only those sections that are listed below
Chapter/Section

This state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.0.

2025 CALIFORNIA PLUMBING CODE 543

544 2025 CALIFORNIA PLUMBING CODE

APPENDIX R

TINY HOUSES

The provisions contained in this appendix are not mandatory unless specifically adopted by a state agency, or referenced in the adopting ordinance.

R 101.0 Tiny Houses.

Frequently asked questions

What is an indirect waste receptor and why is it required?

An indirect waste receptor is an approved fixture, interceptor, or receptacle that receives discharge from an indirect waste pipe so the waste does not directly connect into the drainage system; this prevents backflow or contamination and is required by Chapter 8 (see §801.0).

How high can a clothes‑washer standpipe extend and where can its trap be located?

A clothes‑washer standpipe must extend not more than 30 inches and not less than 18 inches above the trap weir; the trap must be roughed‑in 6 to 18 inches above the floor and cannot be installed below the floor. See §804.1 for the full placement and location restrictions.

When must an air gap be used instead of an air break?

An air gap (the full physical separation) is required where the code identifies a drainage air gap is necessary to protect potable water or when contamination risk is significant; §801.2 sets the air‑gap minimum clearance and the distinction between air gap and air break.

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Related in the CPC

Air gaps, air breaks, and where indirect wastes are required

Indirect waste piping: materials, sizing, traps and venting

Special indirect wastes: chemical, condensate, cooling, steam, pools and appliances

Indirect Wastes

California Plumbing Code