CPC · California Plumbing Code

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

For homeowners: the washer drain standpipe must be between 18" and 30" above the trap weir, the trap must be roughed in 6"–18" above the finished floor (not below the floor), use a 2" trap/drain for a domestic washer, and make sure the receptor prevents splashing and remains accessible; these are the key requirements in the California Plumbing Code (§ 804.1).

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Last reviewed: July 6, 2026

What the code requires — 2-4 sentences

In plain English: a standpipe receptor for a clothes washer must be an approved receptor sized and shaped to prevent splashing or flooding, be readily accessible for inspection/cleaning, have the standpipe height set between 18 inches and 30 inches above the trap weir, and the trap rough‑in must be placed 6–18 inches above the floor. These dimensional and location rules are stated in § 804.1 of the California Plumbing Code.

The single most important rule: make the standpipe and trap arrangement so the washer discharges into an approved receptor that prevents splash/flooding and is accessible for inspection — and follow the 18 in.–30 in. standpipe and 6 in.–18 in. trap‑rough‑in limits in § 804.1.

Note: the user requested grounding in § 801.3.2 as a controlling section. I was unable to find text for § 801.3.2 in the files provided (Chapter 8 listings show § 801.3 exists but a § 801.3.2 text was not present in the retrieved files); therefore this article relies on the available, retrievable CPC sections (notably § 804.1, § 801.2, § 803.3, Table 702.1, and § 1001.2) for citation.

Requirements in detail

Approved receptor — shape, capacity, accessibility

The receptor must be approved for the intended use and of such shape and capacity to prevent splashing or flooding. It must be readily accessible for inspection and cleaning, per § 804.1.

Vertical dimensions (decision‑critical dimensions)

Standpipe height above trap weir: not less than 18 in. and not more than 30 in. (measured above the trap weir) — § 804.1.
Trap rough‑in above finished floor: not less than 6 in. and not more than 18 in. — trap shall not be installed below the floor — § 804.1.

Minimum trap/drain sizing and fixture units

For a domestic clothes washer standpipe, minimum trap size = 2 inches (and the drainage fixture unit (DFU) value listed in Table 702.1) — see the Table 702.1 entry for Clothes Washer, domestic, standpipe and its notes.
Note in Table 702.1: indirect waste receptors shall be sized based on the total drainage capacity of fixtures that drain into them and provide a 2‑inch (50 mm) minimum drain where applicable (see Table 702.1 notes).

Indirect waste connection and air gap/air break

Indirect waste piping must discharge into the drainage system by an air gap or air break as required by the code; the minimum vertical air‑gap dimension where required is 1 inch measured from the lowest point of the indirect waste outlet to the flood‑level rim of the receptor — § 801.2.

Indirect waste piping length, trap and minimum diameter

Indirect waste piping sizing and limits: pipes over 5 ft but less than 15 ft in length must be directly trapped (venting not required for those traps). Indirect waste pipes less than 15 ft shall be not less than the diameter of the drain outlet or tailpiece, and in no case less than 1/2 in. — § 803.3.

Location restrictions

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 — except that standpipes for clothes washers are permitted in toilet and bathroom areas when the washer is installed in the same room — § 804.1.

Table — Decision‑relevant dimensions / values

Item	Required value (bold where key)	Code Reference
Standpipe height above trap weir	18 in. ≤ height ≤ 30 in.	§ 804.1
Trap rough‑in above finished floor	6 in. ≤ rough‑in ≤ 18 in. (trap shall NOT be below floor)	§ 804.1
Minimum trap size for clothes washer standpipe	2 in. (see Table)	Table 702.1 / §702.1 notes
Minimum drain diameter for indirect receptor	2 in. (where table/note applies)	Table 702.1 note
Minimum indirect waste pipe diameter	not less than drain outlet diameter; in no case < 1/2 in.	§ 803.3
Air‑gap minimum (where required)	≥ 1 in. vertical (lowest point of indirect outlet to flood rim)	§ 801.2
Receptor location restriction	Not in toilet room/closet/cupboard/storeroom unless clothes washer is in same bathroom	§ 804.1

Exceptions & special cases

Clothes washer standpipes may be installed in a toilet or bathroom area only when the clothes washer itself is located in that same room (exception in § 804.1).
Indirect waste piping that exceeds 5 ft but is less than 15 ft must be directly trapped; those traps need not be vented per § 803.3.
Table 702.1 contains sizing notes and special fixture unit ratings (for example, self‑service laundries and batteries of washers may have different sizing assumptions) — consult Table 702.1 when designing receptor/drain sizes.

If you need a rule that is specifically in § 801.3.2, I could not locate that exact subsection in the supplied CPC files; please provide the text or allow me to access the official code text so I can cite it directly.

Common mistakes

Installing the trap below the floor. The code prohibits traps for clothes washer standpipes being installed below the floor; the trap must be roughed in 6–18 in. above the floor. (Common error: trap run in basement below floor level.) § 804.1.
Setting the standpipe too short or too tall. Standpipes shorter than 18 in. or taller than 30 in. above the trap weir violate § 804.1 and can cause siphoning, overflow or poor washer drainage.
Using an undersized trap or drain. The minimum trap for a domestic clothes washer standpipe is 2 in. (see Table 702.1); using a 1‑1/2 in. trap is a common noncompliance.
Forgetting indirect‑waste protection (air gap/air break) when required. Indirect waste piping must discharge by air gap or air break where the code requires it (minimum 1 in. gap) — § 801.2.

Worked example — concrete scenario

Scenario: You are installing a domestic clothes washer in a laundry alcove on a raised slab floor.

You plan a standpipe with trap weir roughed in at 12 in. above the finished floor (this is within the required 6–18 in. range). Cite: § 804.1.
You set the standpipe top at 24 in. above the trap weir (that yields a standpipe rim 36 in. above the floor because trap weir is 12 in. above the floor). That is 24 in. above the trap weir, which is between 18–30 in., so compliant with § 804.1.
You specify a 2‑inch trap and 2‑inch drain for the standpipe per Table 702.1 (Clothes Washer, domestic, standpipe — trap size 2 in.; minimum drain 2 in.).
You ensure the indirect waste piping from the washer discharges to the receptor with the required air gap where applicable (minimum 1 in. vertical clearance from outlet to receptor rim) — § 801.2.

Result: The layout conforms to the dimensional and sizing rules in § 804.1 and the trap/drain sizing guidance in Table 702.1, and the indirect connection meets air‑gap requirements per § 801.2.

Related provisions

§ 804.1 — Standpipe receptors (primary controlling text for standpipe height, trap location, and permitted locations).
§ 801.2 — Air gap or air break required for indirect waste discharges (minimum vertical 1 in.).
§ 803.3 — Indirect waste pipe sizing and length requirements (trap required for certain lengths; minimum pipe diameter not less than drain outlet or 1/2 in.).
Table 702.1 and notes — Drainage fixture unit values and minimum trap/drain sizing for clothes washers (trap 2 in.; sizing guidance).
§ 1001.2 — Requirement that each domestic clothes washer be connected to a separate and independent trap (exceptions noted).
§ 803.1 & § 803.2 — Materials and installation references for indirect waste piping (material suitability and copper alloy joint requirements).

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

2025 CALIFORNIA PLUMBING CODE 181

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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 § 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 § 1.6 High relevance — show source text

PLUMBING APPLIANCES, APPURTENANCES, OR FIXTURES	MINIMUM SIZE TRAP AND TRAP ARM7 (inches)	PRIVATE	PUBLIC	ASSEMBLY8
Water Closet, greater than 1.6 GPF Gravity Tank6	3	4.0	6.0	8.0
Water Closet, greater than 1.6 GPF Flushometer Valve6	3	4.0	6.0	8.0

For SI units: 1 inch = 25 mm

Notes: 1 Indirect waste receptors shall be sized based on the total drainage capacity of the fixtures that drain thereinto, in accordance with Table 702.2. 2 Provide a 2 inch (50 mm) minimum drain. 3 For refrigerators, coffee urns, water stations, and similar low demands. 4 For commercial sinks, dishwashers, and similar moderate or heavy demands. 5 Buildings having a clothes-washing area with clothes washers in a battery of three or more clothes washers shall be rated at 6 fixture units each for purposes of sizing common horizontal and vertical drainage piping. 6 Water closets shall be computed as 6 fixture units where determining septic tank sizes based on Appendix H of this code. 7 Trap sizes shall not be increased to the point where the fixture discharge is capable of being inadequate to maintain their self-scouring properties. 8 Assembly [Public Use (see Table 422.1)]. 9 For a bathtub to shower retrofit, a 1 1 / 2 inch (40 mm) trap and trap arm shall be permitted with a maximum shower size of 36 inches (914 mm) in width and 60 inches (1524 mm) in length. See Section 408.6 and Section 408.7. 10 For drainage fixture unit values related to lots within mobilehome parks in all parts of the State of California, see California Code of Regulations, Title 25, Division 1, Chapter 2, Article 5, Section 1268. For drainage fixture unit values related to lots within special occupancy parks in all parts of the State of Cal- ifornia, see California Code of Regulations, Title 25, Division 1, Chapter 2.2, Article 5, Section 2268.

required, and the unit equivalent of fixtures and devices not shown in Table 702.1 shall be based on the size of trap or trap

arm.

Maximum drainage fixture units for a fixture trap and trap arm loadings for sizes up to 4 inches (100 mm) shall be in accordance with Table 702.1(1).

TABLE 702.1(1) MAXIMUM DRAINAGE FIXTURE UNITS FOR A

TRAP AND TRAP ARM*

SIZE OF TRAP AND TRAP ARM (inches)	DRAINAGE FIXTURE UNIT VALUES (DFU)
11⁄4	1 unit
11⁄2	3 units
2	4 units
3	6 units
4	8 units

For SI Units: 1 inch = 25 mm

*** Exception:** On self-service laundries.

702.2 Intermittent Flow. Drainage fixture units for intermittent flow into the drainage system shall be computed on the rated discharge capacity in gallons per minute (gpm) (L/s) in accordance with Table 702.2.

TABLE 702.1(1) MAXIMUM DRAINAGE FIXTURE UNITS FOR A

TRAP AND TRAP ARM*

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 § 2.0 Medium relevance — show source text

dishwasher, or both)|11⁄2|2.0|2.0|––| |Laundry2 (with or without discharge from a clothes washer)|11⁄2|2.0|2.0|2.0| |Service or Mop Basin|2|––|3.0|3.0| |Service or Mop Basin|3|––|3.0|3.0| |Service, flushing rim|3|––|6.0|6.0| |Wash, each set of faucets|––|––|2.0|2.0| |Nonwater Urinal with Drain Cleansing Action|2|1.0|1.0|1.0| |Urinal, integral trap 1.0 GPF2|2|2.0|2.0|5.0| |Urinal, integral trap greater than 1.0 GPF|2|2.0|2.0|6.0| |Urinal, exposed trap2|11⁄2|2.0|2.0|5.0| |Water Closet, 1.6 GPF Gravity Tank6|3|3.0|4.0|6.0| |Water Closet, 1.6 GPF Flushometer Tank6|3|3.0|4.0|6.0| |Water Closet, 1.6 GPF Flushometer Valve6|3|3.0|4.0|6.0|

2025 CALIFORNIA PLUMBING CODE 167

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SANITARY DRAINAGE

TABLE 702.1 DRAINAGE FIXTURE UNIT VALUES (DFU) (continued)

PLUMBING APPLIANCES, APPURTENANCES, OR FIXTURES	MINIMUM SIZE TRAP AND TRAP ARM7 (inches)	PRIVATE	PUBLIC	ASSEMBLY8
Water Closet, greater than 1.6 GPF Gravity Tank6	3	4.0	6.0	8.0
Water Closet, greater than 1.6 GPF Flushometer Valve6	3	4.0	6.0	8.0

For SI units: 1 inch = 25 mm

Notes: 1 Indirect waste receptors shall be sized based on the total drainage capacity of the fixtures that drain thereinto, in accordance with Table 702.2. 2 Provide a 2 inch (50 mm) minimum drain. 3 For refrigerators, coffee urns, water stations, and similar low demands. 4 For commercial sinks, dishwashers, and similar moderate or heavy demands. 5 Buildings having a clothes-washing area with clothes washers in a battery of three or more clothes washers shall be rated at 6 fixture units each for purposes of sizing common horizontal and vertical drainage piping. 6 Water closets shall be computed as 6 fixture units where determining septic tank sizes based on Appendix H of this code. 7 Trap sizes shall not be increased to the point where the fixture discharge is capable of being inadequate to maintain their self-scouring properties. 8 Assembly [Public Use (see Table 422.1)]. 9 For a bathtub to shower retrofit, a 1 1 / 2 inch (40 mm) trap and trap arm shall be permitted with a maximum shower size of 36 inches (914 mm) in width and 60 inches (1524 mm) in length. See Section 408.6 and Section 408.7.

CPC § 1507.1.1 Medium relevance — show source text
End laps shall be 4 inches and
shall be offset by 6 feet.
3.
A single layer of self-adhering polymer modified
bitumen underlayment complying with ASTM
D1970, installed in accordance with the
underlayment and roof covering manufacturers’
installation instructions for the deck material, roof
ventilation configuration, and climate exposure of
the roof covering.|Underlayment shall be one of the following:
1.
Two layers of mechanically fastened underlayment
applied in the following manner: Apply a strip of
underlayment that is half the width of a full sheet
parallel to and starting at the eaves, fastened
sufficiently to hold in place. Starting at the eaves,
apply full-width sheets of underlayment,
overlapping successive sheets half the width of a full
sheet plus 2 inches. Distortions in the underlayment
shall not interfere with the ability of the shingles to
seal. End laps shall be 4 inches and shall be offset by
6 feet.
2.
A strip not less than 4 inches in width of self-
adhering polymer modified bitumen underlayment
complying with ASTM D1970, installed in
accordance with the manufacturer’s installation
instructions for the deck material, shall be applied
over all joints in the roof decking. An approved
underlayment complying with Table 1507.1.1(1) for
the applicable roof covering and basic wind speed
shall be applied over the entire roof over the 4-inch-
wide membrane strips. Underlayment shall be
applied in accordance with this table using the
application requirements for where the maximum
basic wind speed is less than 130 mph.
3.
A single layer of self-adhering polymer modified
bitumen underlayment complying with ASTM
D1970, installed in accordance with the
underlayment and roof covering manufacturers’
installation instructions for the deck material, roof
ventilation configuration, and climate exposure of
the roof covering.| |For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s.|

2025 CALIFORNIA BUILDING CODE 15-9

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

ROOF ASSEMBLIES AND ROOFTOP STRUCTURES
CPC § 404.4 Medium relevance — show source text
Alarms and detection 404.4, 907.2.15 Enclosure 404.6, 707.3.6 Interior finish 404.8 Means of egress 404.9, 404.10, 404.11, 1006.3.2, 1017.3, 1019.3, 1023.2,

1028.2

Smoke control 404.5, 909 Sprinkler protection 404.3 Standby power 404.7 Travel distance 404.9, 1006.2.1, 1006.3, 1017.2

Use 404.2

Attic 202

Access 1209.2 Combustible storage 413.2 Draftstopping 718.4 Insulation 720.3.1

Live load 1607.1 Unusable space fire protection 711.2.6

Ventilation 1202.2 Auditorium (see Assembly Occupancy) 303, 305.1.1 Accessibility Chapter 11B Foyers and lobbies 1030.4 Interior balconies 1030.5

Motion picture projection rooms 409

Stages and platforms 410 Automobile Parking Garage (see Garage, Automobile Parking) Awning 3105 Design and construction 3105.2 Drainage, water 3201.4 Encroachment, public right-of-way 3202.2.3, 3202.3.1, 3202.4 Fire district D102.2.8

Live load 1607.1, 1607.14.1, 1607.14.3 Materials 3105.3

Motor vehicle service stations (canopies) 406.7.2 Permanent D102.2.8

Plastic 2606.10

Balconies Accessibility Chapters 11A and 11B Assembly 1030.5 Construction, exterior 705.2.3.1 Documents 107.2.5, 110.3.7 Guards 1015.2

Live load Table 1607.1 Means of egress 1021, 1030.5 Open mall building 402.4.3, 402.5 Projection 705.2, 705.2.3.1 Public right-of-way encroachments 3202.3.2, 3202.3.3 Travel distance 1017.2.1

Barbecues 2801

Barriers Fire (see Fire Barrier) Pedestrian protection 3306 Smoke (see Smoke Barrier) Vehicle 406.4.2, 1607.11 Basement (see Undergound Buildings) 202 Aircraft hangars 412.3.2 Area modification 506.1.3

Emergency escape 1031 Exits 1006.3.4

Flood loads 1612.1, 1612.4 Height modifications for 510.5 Prohibited 415.11.6.2, 415.6, 415.7, 415.8, 418.1, 421.2 Rodentproofing Appendix F Soil loads 1610.1 Sprinkler protection 903.2.11.1 Waterproofing and dampproofing 1805 Basic Wind Speed 1609.3 Bath and Bathing Rooms (See Toilets and Toilet Rooms) 101.4.3,

CPC § 702.1 Medium relevance — show source text

SANITARY DRAINAGE

TABLE 702.1 DRAINAGE FIXTURE UNIT VALUES (DFU)

PLUMBING APPLIANCES, APPURTENANCES, OR FIXTURES	MINIMUM SIZE TRAP AND TRAP ARM7 (inches)	PRIVATE	PUBLIC	ASSEMBLY8
Bathtub or Combination Bath/Shower	11⁄2	2.0	2.0	––
Bidet	11⁄4	1.0	––	––
Bidet	11⁄2	2.0	––	––
Clothes Washer, domestic, standpipe5	2	3.0	3.0	3.0
Dental Unit, cuspidor	11⁄4	––	1.0	1.0
Dishwasher, domestic, with independent drain2	11⁄2	2.0	2.0	2.0
Drinking Fountain or Water Cooler	11⁄4	0.5	0.5	1.0
Food Waste Disposer, commercial	2	––	3.0	3.0
Floor Drain, emergency	2	––	0.0	0.0
Floor Drain (for additional sizes see Section 702.0)	2	2.0	2.0	2.0
Shower, single-head trap	29	2.0	2.0	2.0
Multi-head, each additional	2	1.0	1.0	1.0
Lavatory	11⁄4	1.0	1.0	1.0
Lavatories in sets	11⁄2	2.0	2.0	2.0
Washfountain	11⁄2	––	2.0	2.0
Washfountain	2	––	3.0	3.0
Mobilehome or Manufactured Home, trap_10_	3	6.0	––	––
Receptor, indirect waste1,3	11⁄2	See footnote1,3	See footnote1,3	See footnote1,3
Receptor, indirect waste1,4	2	See footnote1,4	See footnote1,4	See footnote1,4
Receptor, indirect waste1	3	See footnote1	See footnote1	See footnote1
Sinks	––	––	––	––
Bar	11⁄2	1.0	––	––
Bar2	11⁄2	––	2.0	2.0
Clinical	3	––	6.0	6.0
Commercial with food waste2	11⁄2	––	3.0	3.0
Exam Room	11⁄2	––	1.0	––
Special Purpose2	11⁄2	2.0	3.0	3.0
Special Purpose	2	3.0	4.0	4.0
Special Purpose	3	––	6.0	6.0
Kitchen, domestic2 (with or without food waste disposer, dishwasher, or both)	11⁄2	2.0	2.0	––
Laundry2 (with or without discharge from a clothes washer)	11⁄2	2.0	2.0	2.0
Service or Mop Basin	2	––	3.0	3.

CPC § 801.4 Medium 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 § 2025 Medium 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 § 1.11.0. Medium relevance — show source text
1 Exception 2_||||X|X|||||||||||||||||||| |1010.2|||||||||||||||||||X|||||| |1010.3|||||||||||||||||||X|||||| |1010.4|||||||||||||||||||X|||||| |1010.5|||||||||||||||||||X|||||| |1014.1A, B, C||||||||||X|X|X|X|X|X|||||||||| |1015.5||||||||||X|X|X|X|X|X|||||||||| |1015.6||||||||||X|X|X|X|X|X||||||||||

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 193

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CHAPTER 10

TRAPS AND INTERCEPTORS

1001.0 General.

1001.1 Applicability. This chapter shall govern the materials, design, and installation of traps and interceptors.

1001.2 Where Required. Each plumbing fixture shall be separately trapped by an approved type of liquid seal trap. This section shall not apply to fixtures with integral traps. Not more than one trap shall be permitted on a trap arm. Food waste disposers installed with a set of restaurant, commercial, or industrial sinks shall be connected to a separate trap.

Each domestic clothes washer and each laundry sink shall be connected to a separate and independent trap, except that a trap serving a laundry sink shall also be permitted to receive the waste from a clothes washer set adjacent to it.

The vertical distance between a fixture outlet and the trap weir shall be as short as practicable, but in no case shall the tailpiece exceed 24 inches (610 mm) in length.

One trap shall be permitted to serve a set of not more than three single compartment sinks or laundry sinks of the same depth or three lavatories immediately adjacent to each other and in the same room where the waste outlets are not more than 30 inches (762 mm) apart, and the trap is centrally located where three compartments are installed.

1002.0 Traps Protected by Vent Pipes.

1002.1 Vent Pipes. Each plumbing fixture trap, except as otherwise provided in this code, shall be protected against siphonage, backpressure, and air circulation shall be assured throughout the drainage system using a vent pipe installed in accordance with the requirements of this code.
CPC § 811.0 Medium relevance — show source text
Industrial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .811.0

High temperatures . . . . . . . . . . . . . . .810.1, Table 810.1 Laundries, slaughterhouses, bottling establishments,

and auto wash racks . . . . . . . .711.0, 1010.0 – 1013.0

SPECIFIC GRAVITY,

NATURAL GAS . . . . . . . . . . . . . . . . . . . . . . . . . . .1214.1

SPECIFICATIONS

FOR MATERIALS . . . . . . . . . . . . . . . . . .301.2, Table 1701.1

STACKS . . . . . . . . . . . . . .221.0, 317.1, 706.2, 711.1, 906.1,

907.0, 911.3, 1101.16.2, C 304.3,

C 304.4, C 401.0, C 601.0

STAINLESS STEEL PIPE . . . . . . .Table 313.3, Table 604.1,

605.13, Table 701.2, 705.7

STANDPIPE,

CLOTHES WASHER . . . . . . . . . . . . . . . . . . . . . . . . .804.1

STATION INLETS

AND OUTLETS . . . . . . . . .221.0, 1305.3, Table 1305.3,

1315.0, 1323.1.2,

Table 1323.1.5(1)

STEAM EXHAUST CONDENSER

OR BLOW OFF . . . . . . . . . . . . . . . . . . .810.0, Table 810.1

STERILE EQUIPMENT . . . . . . . . . . . . . . . . . . . . . . . .806.0

STORAGE TANKS

Alternate water sources . . . . . . .1503.3, 1505.4, 1506.4

Hot water . . . . . . . . . . . . . . . . . . . . .505.2, 608.6, 608.7,

L 502.2, L 503.3.2, L 503.3.7

Potable water . . . . . . . . . . . . . . . . . . . . . . . . . . .E 502.7

Rainwater . . . . . . . . . . . . . . . . . . . . . .1602.7.3, 1603.0,

K 102.2, K 103.3, K 105.0

Vacuum drainage . . . . . . . . . . . . . . . . . . . . . .C 501.2.1 STORM DRAINAGE SYSTEMS . . . . .Chapter 11, Appendix D

STORM DRAINS . . . . . . . . . .221.0, 1101.4.4, 1101.6, 1101.11,
CPC § 1103.1 Medium relevance — show source text
(3) Not less than two drains shall be installed in roof areas of 10 000 square feet (929 m [2] ) or less, and not less than one additional drain shall be installed for each 10 000 square feet (929 m [2] ) of roof area exceeding 10 000 square feet (929 m [2] ). (4) Each roof drain shall have a precalibrated, fixed (nonadjustable), and proportional weir (notched) in a standing water collar inside the strainer. No mechanical devices or valves shall be permitted. (5) Pipe sizing shall be based on the pre-calibrated rate of flow (gpm) (L/s) of the pre-calibrated weir for the maximum allowable water depth, and Table 1103.1 and Table 1103.2.

(6) The height of stones or other granular material above the waterproofed surface shall not be considered in water depth measurement, and the roof surface in the vicinity of the drain shall not be recessed to create a reservoir.

(7) Roof design, where controlled-flow roof drainage is used, shall be such that the design roof live load is not less than 30 lb/ft [2] (146 kg/m [2] ) to provide a safety factor exceeding the 15 lb/ft [2] (73 kg/m [2] ) represented by the depth of water stored on the roof in accordance with Table 1105.1(1). (8) Scuppers shall be provided in parapet walls. The distance of scupper bottoms above the roof level at the drains shall not exceed the maximum distances specified in Table 1105.1(2).

(9) Scupper openings shall be not less than 4 inches (102 mm) high and have a width equal to the circumference of

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STORM DRAINAGE

the roof drain required for the area served, sized in accordance with Table 1103.1.

(10)Flashings shall extend above the top of the scuppers.

(11)At a wall or parapet, 45 degree (0.79 rad) cants shall be installed.

(12)Separate storm and sanitary drainage systems shall be provided within the building.

(13)Calculations for the roof drainage system shall be submitted along with the plans to the Authority Having Jurisdiction for approval.

TABLE 1105.1(1) CONTROLLED-FLOW MAXIMUM ROOF WATER DEPTH

ROOF RISE*
(inches) MAXIMUM WATER DEPTH AT
DRAIN
(inches)

Flat 3

2 4

4 5

6 6

For SI units: 1 inch = 25.4 mm
- Vertical measurement from the roof surface at the drain to the highest point of the roof surface served by the drain, ignoring a local depression immediately adjacent to the drain.
TABLE 1105.1(2) DISTANCE OF SCUPPER BOTTOMS ABOVE ROOF
CPC § 1001.0 Medium relevance — show source text
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CHAPTER 10

TRAPS AND INTERCEPTORS

1001.0 General.

1001.1 Applicability. This chapter shall govern the materials, design, and installation of traps and interceptors.

1001.2 Where Required. Each plumbing fixture shall be separately trapped by an approved type of liquid seal trap. This section shall not apply to fixtures with integral traps. Not more than one trap shall be permitted on a trap arm. Food waste disposers installed with a set of restaurant, commercial, or industrial sinks shall be connected to a separate trap.

Each domestic clothes washer and each laundry sink shall be connected to a separate and independent trap, except that a trap serving a laundry sink shall also be permitted to receive the waste from a clothes washer set adjacent to it.

The vertical distance between a fixture outlet and the trap weir shall be as short as practicable, but in no case shall the tailpiece exceed 24 inches (610 mm) in length.

One trap shall be permitted to serve a set of not more than three single compartment sinks or laundry sinks of the same depth or three lavatories immediately adjacent to each other and in the same room where the waste outlets are not more than 30 inches (762 mm) apart, and the trap is centrally located where three compartments are installed.

1002.0 Traps Protected by Vent Pipes.

1002.1 Vent Pipes. Each plumbing fixture trap, except as otherwise provided in this code, shall be protected against siphonage, backpressure, and air circulation shall be assured throughout the drainage system using a vent pipe installed in accordance with the requirements of this code.

1002.2 Fixture Traps. Each fixture trap shall have a protecting vent so located that the developed length of the trap arm from the trap weir to the inner edge of the vent shall be within the distance given in Table 1002.2 but in no case less than two times the diameter of the trap arm. 1002.3 Change of Direction. A trap arm shall be permitted to change direction without the use of a cleanout where such change of direction does not exceed 90 degrees (1.57 rad). Horizontal changes in the direction of trap arms shall be in accordance with Section 706.3.

Exception: For trap arms, 3 inches (80 mm) in diameter and larger, the change of direction shall not exceed 135 degrees (2.36 rad) without the use of a cleanout. 1002.4 Vent Pipe Opening. The vent pipe opening from soil or waste pipe, except for water closets and similar fixtures, shall not be below the weir of the trap.

1003.0 Traps – Described. 1003.1 General Requirements. Each trap, except for traps within an interceptor or similar device shall be selfcleaning. Traps for bathtubs, showers, lavatories, sinks, laun

dry sinks, floor drains, urinals, drinking fountains, dental units, and similar fixtures shall be of standard design, weight and shall be of ABS, cast-brass, cast-iron, lead, PP, PVC, or other approved material. An exposed and readily accessible drawn-copper alloy tubing trap, not less than 17 B & S Gauge (0.045 inch) (1.143 mm), shall be permitted to be used on fixtures discharging domestic sewage.

Exception s :
CPC § 1005.0. Medium relevance — show source text
(3) The installation, change, alteration, or repair of the system does not include a potable water connection or a pump and does not affect other building, plumb- ing, electrical, or mechanical components including structural features, egress, fire-life safety, sanitation, potable water supply piping, or accessibility.

Note: The pump in a clothes washer shall not be considered part of the gray water system.

(4) The gray water shall be contained on the site where it is generated.

(5) Gray water shall be directed to and contained within an irrigation or disposal field.

(6) Ponding or runoff is prohibited and shall be consid- ered a nuisance.

(7) Gray water may be released above the ground sur- face provided at least two (2) inches (51 mm) of mulch, rock, or soil, or a solid shield covers the release point. Other methods which provide equiva- lent separation are also acceptable.

(8) Gray water systems shall be designed to minimize contact with humans and domestic pets.

(9) Water used to wash diapers or similarly soiled or infectious garments shall not be used and shall be diverted to the building sewer.

(10)Gray water shall not contain hazardous chemicals derived from activities such as cleaning car parts, washing greasy or oily rags, or disposing of waste solutions from home photo labs or similar hobbyist or home occupational activities.

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ALTERNATE WATER SOURCES FOR NONPOTABLE APPLICATIONS

(11) Exemption from construction permit requirements of this code shall not be deemed to grant authorization for any gray water system to be installed in a man- ner that violates other provisions of this code or any other laws or ordinances of the enforcing agency.

(12)An operation and maintenance manual shall be pro- vided to the owner. Directions shall indicate that the manual is to remain with the building throughout the life of the system and upon change of ownership or

occupancy.

(13)Gray water discharge from a clothes washer system through a standpipe shall be properly trapped in accordance with Section 1005.0.

1503.1.2 Simple System. Simple systems exceed a clothes washer system and shall comply with the follow- ing:

(1) The discharge capacity of a gray water system shall be determined by Section 1503.8. Simple systems have a discharge capacity of 250 gallons (947 L) per day or less.

(2) Simple systems shall require a construction permit, unless exempted from a construction permit by the Enforcing Agency. The Enforcing Agency shall con- sult with the water purveyor for any public water sys- tem (as defined in Health and Safety Code Section 116275) providing drinking water to the dwelling or non-residential structure before allowing an exemp- tion from a construction permit.

(3) The design of simple systems shall meet generally accepted gray water system design criteria. 1503.1.3 Complex System. Any gray water system that is not a clothes washer system or simple system shall comply with the following:
CPC § 31-2022 Medium relevance — show source text
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"The information contained in this appendix is not part of this American National Standard (ANS) and has not been processed in accordance with ANSI's requirements for an ANS. As such, this appendix may contain material that has not been subjected to public review or a consensus process. In addition, it does not contain requirements necessary for conformance to the standard."

The following IAPMO Installation Standard is included here for the convenience of the users of the Uniform Plumbing Code. It is not considered as a part of the Uniform Plumbing Code unless formally adopted as such. This Installation Standard is an independent, stand-alone document published by the International Association of Plumbing and Mechanical Officials and is printed herein by the expressed written permission of IAPMO.

INSTALLATION STANDARD FOR PEX TUBING SYSTEMS

FOR HOT- AND COLD-WATER DISTRIBUTION

IAPMO IS 31-2022

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

1 Scope

1.1 General

1.1.1 This Standard specifies requirements for the installation of SDR 9 CTS crosslinked polyethylene (PEX) tubing and fittings, including cold-expansion, crimp, press, and mechanical compression fittings, intended for hot- and cold-water distribution systems within buildings.

1.1.2 This Standards applies to

(a) SDR 9 CTS PEX tubing complying with ASTM F876 and pressure-rated in accordance with PPI TR-3; and (b) PEX fitting systems complying with (i) ASTM F877, for mechanical compression fittings and metal or plastic insert fittings with stainless steel press sleeves; (ii) ASTM F1807 or ASTM F2159, for metal or plastic insert fittings with copper crimp rings; (iii) ASTM F1960, for cold expansion fittings with PEX reinforced rings; or (iv) ASTM F2080, for cold expansion fittings with metal compression sleeves. 1.2 Terminology

In this Standard,

(a) “shall” is used to express a requirement, i.e., a provision that the user is obliged to satisfy to comply with the Standard; (b) “should” is used to express a recommendation, but not a requirement; (c) “may” is used to express an option or something permissible within the scope of the Standard; and (d) “can” is used to express a possibility or a capability. Notes accompanying sections of the Standard do not specify requirements or alternative requirements; their purpose is to separate explanatory or informa

tive material from the text. Notes to tables and figures are considered part of the table or figure and can be written as requirements.

1.3 Units of Measurement

SI units are the primary units of record in global commerce. In this Standard, the inch/pound units are shown in parentheses. The values stated in each measurement system are equivalent in application, but each unit system is to be used independently. All references to gallons are to U.S. gallons.

2 Reference Publications
CPC § 1323.13.3 Medium relevance — show source text
2, 1323.13.3| |1326.4 - 1326.10|1326.5 - 1326.11| |1505.6 - 1505.14|1505.5 - 1505.13| |Figure 1505.10|Figure 1505.9| |1506.6 - 1506.13|1506.5 - 1506.12| |1603.3 - 1603.4|1603.4 - 1603.5| |Table 1603.4|Table 1603.5| |1603.5 - 1603.19|1603.6 - 1603.20| |1603.20|1503.2.4| |L 402.9 - L 402.11|L 402.8 - L 402.10| |L 404.9 - L 404.12|L 404.8 - L 404.11| |L 411.5, L 411.6|L 411.2, L411.3| |L 411.7|L 411.4| |L 411.9 - L 411.12|L 411.5 - L 411.8|

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RELATED PUBLICATIONS AND SERVICES

The Documents Listed are Not by this Reference Adopted by The State of California.

IAPMO provides a variety of other products which are useful for inspectors, building officials, architects, engineers,

manufacturers, contractors, plumbers, and apprentices.

IAPMO Headquarters Directory

4755 East Philadelphia Street, Ontario, California 91761-2816

Publication Order Desk Phone: 800-85-IAPMO

Publication Toll Free Fax: 877-85-CODES

E-mail: iapmo@iapmo.org

Website: www.iapmo.org

Free Code Question: 800-201-0335

Uniform Plumbing Code – 2024 Edition:

The Uniform Plumbing Code is the most widely adopted plumbing code in the world. The 2024 edition contains complete “turnkey” requirements for the installation and maintenance of plumbing systems, all in one easy to use book.

Uniform Plumbing Code Illustrated Training Manual:

The UPC Illustrated Training Manual is an excellent reference for anyone involved in the plumbing industry. It contains an extensive definitions section and several hundred comprehensive technical diagrams and illustrations. It serves as a textbook, and it also is useful as a valuable tool for explaining the intent and use of the Code.

Uniform Plumbing Code Study Guide:

This book is the perfect complement to the UPC Illustrated Training Manual. Alone, it constitutes a complete self-study course for learning the UPC. It has hundreds of questions, general practice exams, and plumbing math, pipe sizing exercises and fitting identification. A big help in getting you ready for a certification exam!

Guide to Important Code Questions to the Uniform Plumbing Code:

An excellent reference for learning and understanding plumbing code changes and identifies code changes between editions. It is a useful tool for preparing code change proposals.

Uniform Mechanical Code – 2024 Edition:

The Uniform Mechanical Code contains complete requirements for the installation and maintenance of heating, ventilating, cooking and refrigeration systems.

Uniform Mechanical Code Illustrated Training Manual:

Contains technical diagrams and illustrations that demonstrate the intent and use of the UMC. A great reference for everyone involved in Mechanical HVACR design and installation.

Uniform Mechanical Code Study Guide:
CPC § 309.0 Medium relevance — show source text
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IS 33

Uniform Plumbing Code References for Ductile Iron and PVC Pressure Building Supply and Exterior Cold-Water Piping

The following sections of the 2024 Uniform Plumbing Code apply to ductile iron and PVC pressure building supply and exterior cold-water piping.

Chapter 3 General Regulations

309.0 Workmanship

312.0 Protection of Piping, Materials, and Struc tures

313.0 Hangers, Supports, and Anchors

314.0 Trenching, Excavation, and Backfill

Chapter 6 Water Supply and Distribution

604.0 Materials (water piping)

Table 604.1 Materials for Building Supply and Water Distribution Piping and Fittings

605.4 Ductile Iron Pipe and Joints

605.12 PVC Plastic Pipe and Joints

605.16.2 Plastic Pipe to Other Materials

609.0 Installation, Testing, Unions, and Location

Abbreviations

IAPMO International Association of Plumbing and Mechanical Officials

UPC Uniform Plumbing Code published by IAPMO

AWWA American Water Works Association

CSA Canadian Standards Association

Applicable Standards.

ASME B16.4 Gray Iron Threaded Fittings Classes 125 and 250

ASTM D1785 Poly (Vinyl Chloride) (PVC) Plastic Pipe, Schedules 40, 80, and 120

ASTM D2241 Poly (Vinyl Chloride) (PVC) Pressure-Rated Pipe (SDR Series)

ASTM D2466 Poly (Vinyl Chloride) (PVC) Plastic Pipe Fittings, Schedule 40

ASTM D2467 Poly (Vinyl Chloride) (PVC) Plastic Pipe Fittings, Schedule 80

ASTM F1970 Special Engineered Fittings, Appurtenances or Valves for use in Poly (Vinyl Chloride) (PVC) or Chlorinated Poly (Vinyl Chloride) (CPVC) Systems

AWWA C110 Ductile Iron and Gray-Iron Fittings

AWWA C111 Rubber-Gasket Joints for Ductile-Iron Pressure Pipe and Fittings

AWWA C151 Ductile-Iron Pipe, Centrifugally Cast

AWWA C153 Ductile-Iron Compact Fitting

AWWA C900 Polyvinyl Chloride (PVC) Pressure Pipe and Fabricated Fittings, 4 in. through 12 in. (100 mm through 300 mm)

AWWA C904 Crosslinked Polyethylene (PEX) Pressure Tubing, ½ in. through 3 In. (13 mm through 76 mm), for Water Service

AWWA C907 Injection-Molded Polyvinyl Chloride (PVC) Pressure Fittings, 4 In, through 12 in (100 mm through 300 mm) for Water, Wastewater and Reclaimed Water Service

IAPMO/

ANSI UPC-1 Uniform Plumbing Code

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CPC § 312.0 Medium relevance — show source text
312.0 Protection of Piping, Materials, and Structures

314.0 Trenching, Excavation, and Backfill

701.3 Drainage Fittings

705.5.1.1 Butt Fusion Joints

705.5.1.2 Electro-Fusion Joints

705.5.1.3 Socket-Fusion Joints

723.0 Building Sewer Test

TABLE 1

CLEANOUTS (See Section 4.6.1)

The following standards from Tables 1701.1 and 1701.2 of the 2024 Uniform Plumbing Code apply.

Table 1701.1 Standards

ASTM D2239 Polyethylene (PE) Plastic Pipe (SIDRPR) Based on Controlled Inside Diameter

ASTM D2683 Socket-Type Polyethylene Fittings for Outside Diameter-Controlled Polyethylene Pipe and Tubing

ASTM D3261 Butt Heat Fusion Polyethylene (PE) Plastic Fittings for Polyethylene (PE) Plastic Pipe and Tubing

ASTM F714 Polyethylene (PE) Plastic Pipe (DRPR) Based on Outside Diameter

ASTM F894 Polyethylene (PE) Large Diameter Profile Wall Sewer and Drain Pipe

ASTM F1055 Electrofusion Type Polyethylene Fittings for Outside Diameter Controlled Polyethylene and Crosslinked Polyethylene (PEX) Pipe and Tubing

ASTM F2620 Heat Fusion Joining of Polyethylene Pipe and Fittings

Table 1701.2 Standards

ASTM D2657 Heat Fusion Joining of Polyolefin Pipe and Fittings

IAPMO PS 25 Metallic Fittings for Joining Polyethylene Pipe for Water Service and Yard Piping

Note: For SI units: 1 inch = 25 mm

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

"The information contained in this appendix is not part of this American National Standard (ANS) and has not been processed in accordance with ANSI's requirements for an ANS. As such, this appendix may contain material that has not been subjected to public review or a consensus process. In addition, it does not contain requirements necessary for conformance to the standard."

The following IAPMO Installation Standard is included here for the convenience of the users of the Uniform Plumbing Code. It is not considered as a part of the Uniform Plumbing Code unless formally adopted as such. This Installation Standard is an independent, stand-alone document published by the International Association of Plumbing and Mechanical Officials and is printed herein by the expressed written permission of IAPMO.

INSTALLATION STANDARD FOR PEX TUBING SYSTEMS

FOR HOT- AND COLD-WATER DISTRIBUTION

IAPMO IS 31-2022

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

1 Scope

1.1 General

1.1.1 This Standard specifies requirements for the installation of SDR 9 CTS crosslinked polyethylene (PEX) tubing and fittings, including cold-expansion, crimp, press, and mechanical compression fittings, intended for hot- and cold-water distribution systems within buildings.

1.1.2 This Standards applies to
CPC § 11.0 Medium relevance — show source text
11.0 - 1.11.11_|||X|||||||||||||||||||||| |1.13.0||||||||||||||||||||X||||| |Division II - Scope and
Administration||||||||||||||||||||||||| |101.0||||||||||X|X|X||X|X|||||||||| |102.0||||||||||X|X|X||X|X|||||||||| |103.0||||||||||X|X|X||X|X|||||||||| |104.2 Items 1 & 2||||X|X|||||||||||||||||||| |104.3.1||||||||||X|X|X||X|X|||||||||| |104.4.3.1|X|||||||||||||||||||||||| |105.0||||||||||X|X|X||X|X||||||||||

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.

2 2025 CALIFORNIA PLUMBING CODE

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

CHAPTER 1

ADMINISTRATION

DIVISION I

CALIFORNIA ADMINISTRATION

1.1.0 General.

1.1.1 Title. These regulations shall be known as the Califor- nia Plumbing Code, may be cited as such and will be referred to herein as “this code.” The California Plumbing Code is Part 5 of thirteen parts of the official compilation and publi- cation of the adoption, amendment, and repeal of plumbing regulations to the California Code of Regulations, Title 24, also referred to as the California Building Standards Code. This part incorporates by adoption the 2024 Uniform Plumb- ing Code of the International Association of Plumbing and Mechanical Officials with necessary California amendments.

1.1.2 Purpose. The purpose of this code is to establish the minimum requirements to safeguard the public health, safety and general welfare through structural strength, means of egress facilities, stability, access to persons with disabilities, sanitation, adequate lighting and ventilation, and energy con- servation; safety to life and property from fire and other haz- ards attributed to the built environment; and to provide safety to fire fighters and emergency responders during emergency operations.

1.1.3 Scope. The provisions of this code shall apply to the construction, alteration, movement, enlargement, replace- ment, repair, equipment, use and occupancy, location, main- tenance, removal, and demolition of every building or structure or any appurtenances connected or attached to such buildings or structures throughout the State of California.
CPC § 4.1 Medium relevance — show source text
- 100°F
  (16°C-38°C)|1 h|6 h|2 h|12 h|6 h|24 h| |40°F-60°F
  (4°C-16°C)|2 h|12 h|4 h|24 h|12 h|48 h| |10°F- 40°F
  (-12°C+4°C)|8 h|48 h|16 h|96 h|48 h|8 days| |*If gaps or loose fits are encountered in the system, double these cure times.|*If gaps or loose fits are encountered in the system, double these cure times.|*If gaps or loose fits are encountered in the system, double these cure times.|*If gaps or loose fits are encountered in the system, double these cure times.|*If gaps or loose fits are encountered in the system, double these cure times.|*If gaps or loose fits are encountered in the system, double these cure times.|*If gaps or loose fits are encountered in the system, double these cure times.|
2025 CALIFORNIA PLUMBING CODE 467

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

IS 33

FIGURE 1

LOCATION OF THRUST BLOCKS (STANDARD AND METRIC COMBINED) A COMPARISON OF THRUST-BLOCK AREAS (See Section 4.1)

468 2025 CALIFORNIA PLUMBING CODE

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

IS 33

FIGURE 2

THRUST BLOCK BEARING AREA (See Section 5.2.2)

2025 CALIFORNIA PLUMBING CODE 469

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

IS 33

Uniform Plumbing Code References for Ductile Iron and PVC Pressure Building Supply and Exterior Cold-Water Piping

The following sections of the 2024 Uniform Plumbing Code apply to ductile iron and PVC pressure building supply and exterior cold-water piping.

Chapter 3 General Regulations

309.0 Workmanship

312.0 Protection of Piping, Materials, and Struc tures

313.0 Hangers, Supports, and Anchors

314.0 Trenching, Excavation, and Backfill

Chapter 6 Water Supply and Distribution

604.0 Materials (water piping)

Table 604.1 Materials for Building Supply and Water Distribution Piping and Fittings

605.4 Ductile Iron Pipe and Joints

605.12 PVC Plastic Pipe and Joints

605.16.2 Plastic Pipe to Other Materials

609.0 Installation, Testing, Unions, and Location

Abbreviations

IAPMO International Association of Plumbing and Mechanical Officials

UPC Uniform Plumbing Code published by IAPMO

AWWA American Water Works Association

CSA Canadian Standards Association

Applicable Standards.

ASME B16.4 Gray Iron Threaded Fittings Classes 125 and 250

ASTM D1785 Poly (Vinyl Chloride) (PVC) Plastic Pipe, Schedules 40, 80, and 120

ASTM D2241 Poly (Vinyl Chloride) (PVC) Pressure-Rated Pipe (SDR Series)

Frequently asked questions

May I put a clothes-washer standpipe inside a bathroom?

Yes — but only when the clothes washer is installed in that same bathroom; otherwise indirect waste receptors are not permitted in toilet rooms, closets, cupboards, or storerooms. See § 804.1.

What if my washer is farther than 5 ft from the receptor?

If an indirect waste pipe is over 5 ft but less than 15 ft, that indirect waste pipe must be directly trapped (those traps need not be vented) — § 803.3.

Can I use a 1-1/2 in. trap for a washer standpipe?

No — the code lists a 2‑inch trap for a domestic clothes washer standpipe in Table 702.1; design the standpipe drain to match that minimum.

How high above the trap weir should the standpipe be?

Between 18 inches and 30 inches above the trap weir per § 804.1.

I requested § 801.3.2 — why isn't it cited here?

I could not find a retrievable text for § 801.3.2 in the supplied CPC files. The guidance above is grounded in the retrievable sections (notably § 804.1, § 801.2, § 803.3, and Table 702.1). If you can provide the text of § 801.3.2 or allow access to the complete code, I will incorporate and cite it directly.

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