CPC · California Plumbing Code

How to size drains and vents using drainage fixture units (DFU)

Q: My pump discharges at 10 gpm — how many DFUs is that?

If it’s intermittent flow use Table 702.2 : >7½–15 gpm = 2 DFU . If the flow is continuous, use § 702.3 : 2 DFU = 1 gpm of continuous flow.

DFUs are the code’s fixture‑unit numbers (see Table 702.1 and § 702.1). Add the DFU for each fixture, apply intermittent/continuous conversions when needed, respect trap/trap‑arm maxima (Table 702.1(1)), and use the DFU total to pick pipe and vent sizes from the drainage/vent sizing tables.

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Last reviewed: July 6, 2026

What the code requires — 2-4 sentences

The California Plumbing Code assigns each plumbing fixture a drainage fixture unit (DFU) value; designers add DFUs to get a total load and then size traps, branches, stacks, building drains, and vents from those totals. See § 702.0 and § 702.1 for the fixture-unit concept and the DFU table (Table 702.1) that lists the unit values to use. The code also limits the maximum DFU that may be carried by a single trap/trap arm (Table 702.1(1)) and provides special rules for intermittent and continuous flows (§ 702.2–702.3).

The single most important rule: use the DFU values in Table 702.1 to convert each fixture to fixture units, total those units for the relevant pipe/vent interval, and then select pipe/vent sizes from the applicable sizing tables based on that total.

Requirements in detail

1) Defined term and where it appears

DFU (drainage fixture unit) — a unit value assigned to each fixture type for sizing sanitary drainage and vents. See § 702.0 (Fixture Unit Equivalents) and Table 702.1 for the values.

2) Assign DFU values (what to look up)

For every fixture, find the DFU in Table 702.1 and use that number for sizing the trap, trap arm, branch, stack, building drain, or sewer. The Table is the controlling source for fixture values.

Decision‑relevant quick reference (common fixtures)

Fixture (typical)	Typical DFU (private/public/assembly where differentiated)	Code reference
Lavatory (lavatory basin)	1.0 (typical private)	§ 702.1, Table 702.1
Water closet, 1.6 GPF	3.0 (private)	§ 702.1, Table 702.1
Bathtub or Shower	2.0 (typical)	§ 702.1, Table 702.1
Kitchen sink (commercial) / Food‑prep sink	3.0 (commercial)	§ 702.1, Table 702.1
Floor drain	2.0	§ 702.1, Table 702.1
Mop/service basin	3.0 (commercial)	§ 702.1, Table 702.1

(Use the exact cell in Table 702.1 for the occupancy type — the Table differentiates private, public, and assembly where applicable.)

3) Trap / trap arm limits

The maximum DFU load permitted on a single trap/trap arm for common trap sizes is listed in Table 702.1(1) (for traps up to 4 inches). For example, a 1‑1/2 inch trap is limited to 3 DFU; a 3 inch trap to 6 DFU; a 4 inch trap to 8 DFU. Do not exceed these maxima (exception noted for self‑service laundries).

4) Intermittent and continuous flow rules

If the discharge is intermittent (pulsed equipment), convert the rated gpm to DFU per Table 702.2 (e.g., up to 7½ gpm = 1 DFU, >7½–15 gpm = 2 DFU, etc.). For continuous flows use the conversion in § 702.3 where 2 DFU = 1 gpm of continuous flow. Apply these conversions when a fixture or device does not have a listed DFU.

5) From DFU totals to pipe/vent sizes

Once DFUs are totaled for the branch/stack/interval, use the appropriate sizing table (for example, Table 703.2 or the vent sizing tables and developed length rules) to select pipe and vent sizes. The DFU total is the key input to those sizing tables. (Table and section references for pipe/vent sizing appear elsewhere in the CPC; the DFU total comes from Table 702.1.)

At-a-glance trap-size limits (from Table 702.1(1))

Trap size (in.)	Max DFU on that trap/trap arm	Code reference
1-1/4 in.	1 DFU	Table 702.1(1) / § 702.1
1-1/2 in.	3 DFU	Table 702.1(1) / § 702.1
2 in.	4 DFU	Table 702.1(1) / § 702.1
3 in.	6 DFU	Table 702.1(1) / § 702.1
4 in.	8 DFU	Table 702.1(1) / § 702.1

Exceptions & special cases

Trap/trap‑arm maxima: there is a noted exception for self‑service laundries in Table 702.1(1). Check the footnote in the Table for that special case.
Fixtures or devices not listed in Table 702.1: determine a unit equivalent based on the size of the trap or trap arm (the code directs you to use trap size when no DFU is listed).
High‑flow intermittent or continuous sources (pumps, ejectors, condensate): use Table 702.2 or § 702.3 conversions rather than the standard fixture entries. For discharge >50 gpm the Authority Having Jurisdiction must be consulted.

If you need the exact cell for an uncommon fixture, consult Table 702.1 directly; the Table also separates private/public/assembly where values differ.

Common mistakes

Adding the wrong units: using water‑supply fixture units (WSFU) instead of DFU — DFUs are for drainage and vents, WSFU for water supply. Check you’re using Table 702.1 values.
Ignoring trap/trap‑arm limits: connecting more DFU to a trap than allowed by Table 702.1(1) (e.g., using a 1‑1/2" trap for many fixtures) can cause inadequate drainage and is not permitted.
Forgetting intermittent/continuous conversions: pumps, condensate, and some appliances must be converted via Table 702.2 or § 702.3 rather than treated as a single DFU.
Sizing vents only by pipe count and not by DFU + developed length: vent sizing requires the DFU total plus developed length — refer to vent sizing rules/tables in Chapter 4/Appendix C as applicable. (DFU totals come from Table 702.1.)

Worked example — small commercial kitchen (numbers)

Scenario: One food‑prep sink, one mop/service basin, three floor drains (kitchen), all discharging to a common kitchen branch that will connect to a grease interceptor.

Step 1 — DFU lookup (Table 702.1):

Food‑prep sink (commercial): 3 DFU.
Mop/service basin: 3 DFU.
Floor drain (each): 2 DFU × 3 = 6 DFU.

Step 2 — Total DFU for kitchen drain line:

3 (food prep) + 3 (mop) + 6 (3 floor drains) = 12 DFU. (This same example and counting is shown in the CPC grease‑interceptor sizing example.)

Step 3 — Use the DFU total:

Use the total 12 DFU to (a) size the kitchen branch and piping from Table 703.2 or equivalent sizing table and (b) size the grease interceptor per Table 1014.3.6 (the CPC example shows a 12 DFU kitchen line used to select a 750 gal interceptor in that example). The DFU count is the controlling input coming from Table 702.1.

Related provisions

§ 702.2 (Intermittent Flow) — conversion of gpm to DFU for intermittent discharges.
§ 702.3 (Continuous Flow) — conversion for continuous flows (2 DFU = 1 gpm).
§ 703.1–703.2 and Table 703.2 — use DFU totals to size drainage piping (branches, stacks, building drains).
Appendix C / § C 401.1 — vent sizing by developed length uses DFU totals; consult when vents are long or stacks have offsets.
Table 702.1(1) — maximum DFU per trap/trap arm (trap size limits and an exception for laundries).

Note: the code text for § 702.0 is listed in the CPC table of contents and Table 702.1 is reproduced in the CPC; most of the specific DFU values and the trap/trap‑arm maxima above are taken directly from Table 702.1 and Table 702.1(1) in the CPC. If you want the full text of § 702.0 verbatim or every cell of Table 702.1, consult the official CPC Table 702.1 pages; the CPC also provides examples (e.g., grease‑interceptor sizing) that illustrate DFU addition in practice.

Code references

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

CPC § 705.10 Medium relevance — show source text

Waste,
and Vent (DWV), Sewer, Sanitary, and Storm Plumbing Sys-
tems for Above and Below Ground Use|Joints|705.10|

340 2025 CALIFORNIA PLUMBING CODE

REFERENCED STANDARDS

TABLE 1701.1 (continued) REFERENCED STANDARDS

STANDARD NUMBER	STANDARD TITLE	APPLICATION	REFERENCED SECTION
ASTM C1540-2020	Standard Specification for Heavy-Duty Shielded Couplings Joining Hubless Cast Iron Soil Pipe and Fittings	Joints	705.2.2
ASTM C1563-2008 (R2021)	Standard Test Method for Gaskets for Use in Connection with Hub and Spigot Cast Iron Soil Pipe and Fittings for Sanitary Drain, Waste, Vent, and Storm Piping Applications	Joints	705.2.2
ASTM C1822-2021	Standard Specification for Insulating Covers on Accessible Lavatory Piping	Miscellaneous	403.3
ASTM D1253-2014	Standard Test Method for Residual Chlorine in Water	Miscellaneous	1506.10.6, 1603.4.1
ASTM D1785-2021a	Standard Specification for Poly (Vinyl Chloride) (PVC) Plastic Pipe, Schedules 40, 80, and 120	Piping	Table 604.1, Table 701.2
ASTM D2235-2021	Standard Specification for Solvent Cement for Acrylonitrile- Butadiene-Styrene (ABS) Plastic Pipe and Fittings	Joints	705.1.2
ASTM D2239-2021	Standard Specification for Polyethylene (PE) Plastic Pipe (SIDR-PR) Based on Controlled Inside Diameter	Piping	Table 604.1
ASTM D2241-2020	Standard Specification for Poly (Vinyl Chloride) (PVC) Pressure- Rated Pipe (SDR Series)	Piping	Table 604.1
ASTM D2464-2015	Standard Specification for Threaded Poly (Vinyl Chloride) (PVC) Plastic Pipe Fittings, Schedule 80	Fittings	Table 604.1
ASTM D2466-2021	Standard Specification for Poly (Vinyl Chloride) (PVC) Plastic Pipe Fittings, Schedule 40	Fittings	Table 604.1
ASTM D2467-2020	Standard Specification for Poly (Vinyl Chloride) (PVC) Plastic Pipe Fittings, Schedule 80	Fittings	Table 604.1
ASTM D2513-2020	Standard Specification for Polyethylene (PE) Gas Pressure Pipe, Tubing, and Fittings	Piping	1208.5.4, 1208.5.6.2, 1208.5.10.2, 1210.1.7.1(1)
ASTM D2564-2020	Standard Specification for Solvent Cements for Poly (Vinyl Chloride) (PVC) Plastic Piping Systems	Joints	605.12.2, 705.6.

CPC § 304.8 Medium relevance — show source text

200
| |1700
|194
|389
|702
|1220
|1840
|3300
|9130
|17 600
| |1800
|188
|377
|680
|1180
|1780
|3200
|8850
|17 100
| |1900
|183
|366
|661
|1140
|1730
|3110
|8590
|16 600
| |2000|178|356|643|1110|1680|3020|8360|~~16 200~~|

For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 pound-force per square inch = 6.8947 kPa

Table entries are rounded to 3 significant digits.

270 2025 CALIFORNIA PLUMBING CODE

FUEL GAS PIPING

TABLE 1215.2(36) POLYETHYLENE PLASTIC TUBING [NFPA 54: TABLE 6.3.1(m)] [2]

Col1	GAS:	UNDILUTED PROPANE
	INLET PRESSURE:	11.0 in. w.c.
	PRESSURE DROP:	0.5 in. w.c.
	SPECIFIC GRAVITY:	1.50
INTENDED USE: SIZING BETWEEN INTEGRAL 2-STAGE REGULATOR AT TANK OR SECOND-STAGE (LOW-PRESSURE REGULATOR) AND THE BUILDING	INTENDED USE: SIZING BETWEEN INTEGRAL 2-STAGE REGULATOR AT TANK OR SECOND-STAGE (LOW-PRESSURE REGULATOR) AND THE BUILDING	INTENDED USE: SIZING BETWEEN INTEGRAL 2-STAGE REGULATOR AT TANK OR SECOND-STAGE (LOW-PRESSURE REGULATOR) AND THE BUILDING
	PLASTIC TUBING SIZE (CTS)1 (inch)	PLASTIC TUBING SIZE (CTS)1 (inch)
NOMINAL OD:	1⁄2	1
DESIGNATION:	SDR 7	SDR 11
ACTUAL ID:	0.445	**0.

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|

xxii 2025 CALIFORNIA PLUMBING CODE

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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 § 0.375 Medium relevance — show source text
2**| |||TUBE SIZE (inch)|TUBE SIZE (inch)|TUBE SIZE (inch)|TUBE SIZE (inch)|TUBE SIZE (inch)|TUBE SIZE (inch)|TUBE SIZE (inch)|TUBE SIZE (inch)|TUBE SIZE (inch)| |NOMINAL:|K & L:|1⁄4|3⁄8|1⁄2|5⁄8|3⁄4|1|11⁄4|11⁄2|2| |NOMINAL:|ACR:|3⁄8|1⁄2|5⁄8|3⁄4|7⁄8|11⁄8|13⁄8|–|–| |OUTSIDE:|OUTSIDE:|0.375|0.500|0.625|0.750|0.875|1.125|1.375|1.625|2.125| |INSIDE:1|INSIDE:1|0.305|0.402|0.527|0.652|0.745|0.995|1.245|1.481|1.959| |LENGTH (feet)|LENGTH (feet)|CAPACITY IN CUBIC FEET OF GAS PER HOUR|CAPACITY IN CUBIC FEET OF GAS PER HOUR|CAPACITY IN CUBIC FEET OF GAS PER HOUR|CAPACITY IN CUBIC FEET OF GAS PER HOUR|CAPACITY IN CUBIC FEET OF GAS PER HOUR|CAPACITY IN CUBIC FEET OF GAS PER HOUR|CAPACITY IN CUBIC FEET OF GAS PER HOUR|CAPACITY IN CUBIC FEET OF GAS PER HOUR|CAPACITY IN CUBIC FEET OF GAS PER HOUR| |10
20
30
40
50|10
20
30
40
50|303
208
167
143
127|625
430
345
295
262|1270
874
702
601
532|2220
1530
1230
1050
931|3150
2170
1740
1490
1320|6740
4630
3720
3180
2820|12 100
8330
6690
5730
5080|19 100
13 100
10 600
9030
8000|39 800
27 400
22 000
18 800
16
CPC § 309.0 Medium relevance — show source text
2025 CALIFORNIA PLUMBING CODE 469

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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

470 2025 CALIFORNIA PLUMBING CODE

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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

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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 § 304.8 Medium relevance — show source text
400
| |650
|194
|389
|702
|1220
|1840
|3300
|9130
|17 600
| |700
|187
|374
|674
|1170
|1760
|3170
|8770
|16 900
| |750
|180
|360
|649
|1130
|1700
|3050
|8450
|16 300
| |800
|174
|348
|627
|1090
|1640
|2950
|8160
|15 800
| |850
|168
|336
|607
|1050
|1590
|2850
|7890
|15 300
| |900
|163
|326
|588
|1020
|1540
|2770
|7650
|14 800
| |950
|158
|317
|572
|990
|1500
|2690
|7430
|14 400
| |1000
|154
|308
|556
|963
|1450
|2610
|7230
|14 000
| |1100
|146
|293
|528
|915
|1380
|2480
|6870
|13 300
| |1200
|139
|279
|504
|873
|1320
|2370
|6550
|12 700
| |1300
|134
|267
|482
|836
|1260
|2270
|6270
|12 100
| |1400
|128
|257
|463
|803
|1210
|2180
|6030
|11 600
| |1500
|124
|247
|446
|773
|1170
|2100
|5810
|11 200
| |1600
|119
|239
|431
|747
|1130
|2030
|5610
|10 800
| |1700
|115
|231
|417
|723
|1090
|1960
|5430
|10 500
| |1800
|112
|224
|404
|701
|1060
|1900
|5260
|10 200
| |1900
|109
|218
|393
|680
|1030
|1850
|5110
|9900
| |2000|106|212|382|662|1000|1800|4970|~~9600~~|

For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283 m [3] /h, 1 pound-force per square inch = 6.8947 kPa
```
  - Table entries are rounded to 3 significant digits.
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2025 CALIFORNIA PLUMBING CODE 257

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FUEL GAS PIPING
California Plumbing Code Medium relevance — show source text

5
10
15
20|NA
NA
NA
NA
NA|NA
NA
NA
NA
NA|38
35
NA
NA
NA|NA
NA
NA
NA
NA|NA
NA
NA
NA
NA|73
67
59
NA
NA|NA
NA
NA
NA
NA|NA
NA
NA
NA
NA|123
115
105
95
80|NA
NA
NA
NA
NA|NA
NA
NA
NA
NA|200
183
170
156
144|163
NA
NA
NA
NA|520
NA
NA
NA
NA|273
252
235
217
202| |30|2
5
10
15
20
30|NA
NA
NA
NA
NA
NA|NA
NA
NA
NA
NA
NA|41
NA
NA
NA
NA
NA|NA
NA
NA
NA
NA
NA|NA
NA
NA
NA
NA
NA|81
75
66
NA
NA
NA|NA
NA
NA
NA
NA
NA|NA
NA
NA
NA
NA
NA|136
127
113
105
88
NA|NA
NA
NA
NA
NA
NA|NA
NA
NA
NA
NA
NA|215
196
182
168
155
NA|158
NA
NA
NA
NA
NA|578
NA
NA
NA
NA
NA|302
279
260
240
223
182| |50|2
5
10
15
20
30|NA
NA
NA
NA
NA
NA|NA
NA
NA
NA
NA
NA|NA
NA
NA
NA
NA
NA|NA
NA
NA
NA
NA
NA|NA
NA
NA
NA
NA
NA|91
NA
NA
NA
NA
NA|NA
NA
NA
NA
NA
NA|NA
NA
NA
NA
NA
NA|160
149
136
124
NA
NA|NA
NA
NA
NA
NA
NA|NA
NA
NA
NA
NA
NA|250
228
212
195
180
NA|NA
NA
NA
NA
NA
NA|NA
NA
NA
NA
NA
NA|350
321
301
278
258
NA| |Minimum
internal area of
chimney
(square inches)|Minimum
internal
CPC § 304.8 Medium relevance — show source text
700
|26 500
| |850
|283
|566
|1020
|1770
|2670
|4800
|13 300
|25 700
| |900
|274
|549
|990
|1710
|2590
|4650
|12 900
|24 900
| |950
|266
|533
|961
|1670
|2520
|4520
|12 500
|24 200
| |1000
|259
|518
|935
|1620
|2450
|4400
|12 200
|23 500
| |1100
|246
|492
|888
|1540
|2320
|4170
|11 500
|22 300
| |1200
|234
|470
|847
|1470
|2220
|3980
|11 000
|21 300
| |1300
|225
|450
|811
|1410
|2120
|3810
|10 600
|20 400
| |1400
|216
|432
|779
|1350
|2040
|3660
|10 100
|19 600
| |1500
|208
|416
|751
|1300
|1960
|3530
|9760
|18 900
| |1600
|201
|402
|725
|1260
|1900
|3410
|9430
|18 200
| |1700
|194
|389
|702
|1220
|1840
|3300
|9130
|17 600
| |1800
|188
|377
|680
|1180
|1780
|3200
|8850
|17 100
| |1900
|183
|366
|661
|1140
|1730
|3110
|8590
|16 600
| |2000|178|356|643|1110|1680|3020|8360|~~16 200~~|

For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 pound-force per square inch = 6.8947 kPa
- Table entries are rounded to 3 significant digits.
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FUEL GAS PIPING

TABLE 1215.2(36) POLYETHYLENE PLASTIC TUBING [NFPA 54: TABLE 6.3.1(m)] [2]

Col1 GAS: UNDILUTED PROPANE

INLET PRESSURE: ** 11.0 in. w.c.**

PRESSURE DROP: ** 0.5 in. w.c.**

SPECIFIC GRAVITY: ** 1.

CPC § 25.4 Medium relevance — show source text

22
55
73
85
97
123|932
715
702
681
662
642
605|518
445
438
426
413
401
376| |100|0
2
5
10
15
20
30
50|NA
NA
NA
NA
NA
NA
NA
NA|NA
NA
NA
NA
NA
NA
NA
NA|NA
NA
NA
NA
NA
NA
NA
NA|0
10
26
33
40
47
NA
NA|218
194
189
182
174
166
NA
NA|NA
NA
NA
NA
NA
NA
NA
NA|0
12
33
43
50
59
78
NA|407
354
347
335
321
311
290
NA|NA
NA
NA
NA
NA
NA
NA
NA|0
13
40
53
62
71
92
147|665
566
557
542
528
513
483
428|400
375
369
361
353
344
NA
NA|0
18
52
68
80
90
115
180|997
831
820
801
782
763
726
651|560
510
504
493
482
471
449
405|

For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m [2]

NA: Not applicable.

110 2025 CALIFORNIA PLUMBING CODE

WATER HEATERS

TABLE 510.1.2(1) TYPE B DOUBLE-WALL GAS VENT [NFPA	Col2	Col3	Col4	Col5	54: TABLE 13.1(a)] (continued)	Col7	Col8	Col9	Col10	Col11	Col12	Col13	Col14	Col15	Col16	Col17
					NUMBER OF APPLIANCES:	NUMBER OF APPLIANCES:	NUMBER OF APPLIANCES:	NUMBER OF APPLIANCES:	NUMBER OF APPLIANCES:	NUMBER OF APPLIANCES:	SINGLE	SINGLE	SINGLE	SINGLE	SINGLE	SINGLE
					APPLIANCE TYPE:	APPLIANCE TYPE:	APPLIANCE TYPE:	APPLIANCE TYPE:	**APPLIANCE

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.|
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IS 33

FIGURE 1

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

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IS 33

FIGURE 2

THRUST BLOCK BEARING AREA (See Section 5.2.2)

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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)
CPC § 102.3 Medium relevance — show source text
1

CEBC—25: California Existing Building Code

102.3, 1011.5.2, 1103.1, 1104.18, 1105.5.2

CMC—25: California Mechanical Code

201.3, 308.3, 605.1, 605.2.1.1, 605.2.1.2, 605.2.1.3, 605.2.1.4, 605.2.1.5, 605.3, 605.4, 605.4.2.3, 605.4.2.5, 605.5.2, 605.7, 606.1, 606.2, 608.1, 608.3, 608.4, 608.5, 608.8, 608.9.1, 608.10, 608.17, 610.1.1, 903.2.11.4, 904.14, 907.3.1, 909.1, 909.10.2, 909.13.1, 910.4.7, 915.6.1, 1006.2.2.3, 1011.16, 1020.6.1, 1207.4.7, 1207.6.1, 1207.6.1.2.2, 1207.11.8, 2104.2.1, 2105.3, 2301.1, 2301.6, 2309.3.1.2, 2311.3.1, 2311.4.3, 2311.8.2, 2311.8.8, 2311.8.10, 2404.9, 2404.9.2, 2504.5, 2703.2.2, 2703.10.4, 2703.14, 2803.2, 2803.3, 3001.1, 3003.1, 3004.2, 3108.12.1, 3108.12.2, 3703.5, 3804.1.1.7, 3904.1, 3905.3, Table 5003.1.1(1), 5003.8.4.2, 5003.8.5.2, 5003.8.6.2, 5004.3.1, 5303.7.6, 5303.16.9, 5305.5, 5306.2.2, 5306.2.3, 5307.4.4, 5504.2.1.3, 5504.2.2.3, 5505.4.1.1, 5701.3, 5703.6.1, 5704.2.8.9, 5705.3.7.5.1, 5706.2, 5706.4.4, 6003.1.3, 6003.2.3.2, 6004.2.2.7, 6005.3.1, 6005.3.2, 6103.2.1.7

CPC—25: California Plumbing Code
CPC § 904.0. High relevance — show source text
VENTS

smaller than the minimum vent pipe size required for a fixture served, or by Section 904.0. 908.2 Horizontal Wet Venting for a Bathroom Group. A bathroom group located on the same floor level shall be permitted to be vented by a horizontal wet vent where all of the conditions of Section 908.2.1 through Section 908.2.5 are met.

908.2.1 Vent Connection. The dry vent connection to the wet vent shall be an individual vent for the bidet, shower, or bathtub. One or two vented lavatory(s) shall be permitted to serve as a wet vent for a bathroom group. Only one wet-vented fixture drain or trap arm shall discharge upstream of the dry-vented fixture drain connection. Dry vent connections to the horizontal wet vent shall be in accordance with Section 905.2 and Section

905.3.

908.2.2 Size. The wet vent shall be sized based on the fixture unit discharge into the wet vent. The wet vent shall be not less than 2 inches (50 mm) in diameter for 4 drainage fixture units (dfu) or less, and not less than 3 inches (80 mm) in diameter for 5 dfu or more. The dry vent shall be sized in accordance with Table 702.1 and Table 703.2 based on the total fixture units discharging into the wet vent.

908.2.3 Trap Arm. The length of the trap arm shall not exceed the limits in Table 1002.2. The trap size shall be in accordance with Section 1003.3. The vent pipe opening from the horizontal wet vent, except for water closets and similar fixtures, shall not be below the weir of the trap.

908.2.4 Water Closet. The water closet fixture drain or trap arm connection to the wet vent shall be downstream of fixture drain or trap arm connections to the horizontal wet vent.

908.2.5 Additional Fixtures. Additional fixtures shall discharge downstream of the wet vent system and be conventionally vented. Only the fixtures within the bathroom group shall connect to the wet-vented horizontal branch.

909.0 Special Venting for Island Fixtures. 909.1 General. Traps for island sinks and similar equipment shall be roughed in above the floor and shall be permitted to be vented by extending the vent as high as possible, but not less than the drainboard height and then returning it downward and connecting it to the horizontal sink drain immediately downstream from the vertical fixture drain. The return vent shall be connected to the horizontal drain through a wyebranch fitting and shall, in addition, be provided with a foot vent taken off the vertical fixture vent by means of a wye branch immediately below the floor and extending to the nearest partition and then through the roof to the open air, or shall be permitted to be connected to other vents at a point not less than 6 inches (152 mm) above the flood-level rim of the fixtures served. Drainage fittings shall be used on the vent below the floor level, and a slope of not less than [1] ⁄ 4 inch per foot (20.8 mm/m) back to the drain shall be maintained. The return bend used under the drainboard shall be a one-piece
CPC § 304.3.1 High relevance — show source text
be sized based on the total accumulated connected load at each story or branch interval.

C 304.3.1 Horizontal Stack Offsets. Horizontal

stack offsets shall be sized in accordance with Table C 304.2 as required for building drains.

C 304.3.2 Vertical Stack Offsets. Vertical stack off sets shall be sized in accordance with Table C 304.3 as required for stacks.

C 304.4 Horizontal Stack Offset and Horizontal Branch

Connections. Horizontal branch connections shall not connect to a horizontal stack offset or within 2 feet (610 mm) above or below the offset where such horizontal offset is located more than four branch intervals below the top of the stack.

C 401.0 Vent System Sizing. C 401.1 Size of Vents. The size of vent piping shall be determined from the developed length and the total number of drainage fixture units connected in accordance with Table C 401.1. Vents shall be not less than one-half the required size of the drainage pipe size served as determined by Table C 304.3 for horizontal fixture branches and stacks nor less than 1 [1] ⁄ 4 inches

(32 mm) in diameter. The drainage system shall be vented by not less than one vent pipe which shall be not less than one-half the size of the required building drain and which shall extend from the building drain or extension of building drain to the outdoors. Vents shall be installed in accordance with Chapter 9. C 401.2 Vent Stack. A vent stack shall be required for a drainage stack that extends five or more branch intervals above the building drain or horizontal branch. The developed length of the vent stack shall be measured from the lowest connection of a branch vent to the termination outdoors.

C 401.3 Branch Vents. Where branch vents exceed 40 feet (12 192 mm) in developed length, such vent shall be increased by one pipe size for the entire developed length of the vent pipe. C 401.4 Venting Horizontal Offsets. Drainage stacks with horizontal offsets shall be vented where five or more branch intervals are located above the offset. The upper and lower section of the horizontal offset shall be vented in accordance

with Section C 401.4.1 and Section C 401.4.2.

C 401.4.1 Venting Upper Section. The vent for the upper section of the stack shall be vented as a separate stack with a vent stack connection installed at the base of the drainage stack. Such vent stack shall connect below the lowest horizontal branch or building drain. Where vent stack connects to the building drain, the connection shall be located downstream of the drainage stack and within a distance of 10 times the diameter of the drainage stack. C 401.4.2 Venting Lower Section. The vent for the lower section of the stack shall be vented by a yoke vent connecting between the offset and the next lower horizontal branch using a wye-branch fitting. The size of the yoke vent and connection shall be not less in diameter

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APPENDIX C

TABLE C 303.3 DRAINAGE FIXTURE UNIT VALUES (DFU) FOR BATHROOM GROUPS [1, 2]
CPC § 4.5 High relevance — show source text
0|4.5|4.1|4.1| |Each Additional1⁄2 Bath|0.5|0.1|0.4|0.4| |Each Additional Bathroom Group|1.0|0.5|0.8|0.8| |Other Groups of Fixtures|Other Groups of Fixtures|Other Groups of Fixtures|Other Groups of Fixtures|Other Groups of Fixtures| |Bathroom Group (1.6 GPF Flushometer Value)|6.0|2.5|4.0|1.7| |Kitchen Group (Sink and Dishwasher)|2.0|2.0|1.5|1.5| |Laundry Group (Sink and Clothes Washer)|5.0|5.0|3.0|3.0|

Notes: 1 A bathroom group, for this table, consists of one water closet, up to two lavatories, and either one bathtub or one shower. 2 A half-bath or powder room, for this table, consists of one water closet and one lavatory. 3 Multi-unit dwellings with individual water heaters use the same WSFU as for individual dwellings.

C 304.2 Size of Building Drain and Building Sewer. The maximum number of drainage fixture units allowed on the building drain or building sewer of a given size shall be in accordance with Table C 304.2. The size of a building drain or building sewer serving a water closet shall be not less than 3 inches (80 mm).

C 304.3 Size of Horizontal Branch or Vertical Stack. The maximum number of drainage fixture units allowed on a horizontal branch or vertical soil or waste stack of a given size shall be in accordance with Table C 304.3. Stacks shall

be sized based on the total accumulated connected load at each story or branch interval.

C 304.3.1 Horizontal Stack Offsets. Horizontal

stack offsets shall be sized in accordance with Table C 304.2 as required for building drains.

C 304.3.2 Vertical Stack Offsets. Vertical stack off sets shall be sized in accordance with Table C 304.3 as required for stacks.

C 304.4 Horizontal Stack Offset and Horizontal Branch

Connections. Horizontal branch connections shall not connect to a horizontal stack offset or within 2 feet (610 mm) above or below the offset where such horizontal offset is located more than four branch intervals below the top of the stack.

C 401.0 Vent System Sizing. C 401.1 Size of Vents. The size of vent piping shall be determined from the developed length and the total number of drainage fixture units connected in accordance with Table C 401.1. Vents shall be not less than one-half the required size of the drainage pipe size served as determined by Table C 304.3 for horizontal fixture branches and stacks nor less than 1 [1] ⁄ 4 inches

(32 mm) in diameter. The drainage system shall be vented by not less than one vent pipe which shall be not less than one-half the size of the required building drain and which shall extend from the building drain or extension of building drain to the outdoors. Vents shall be installed in accordance with Chapter 9. C 401.2 Vent Stack. A vent stack shall be required for a drainage stack that extends five or more branch intervals above the building drain or horizontal branch. The developed length of the vent stack shall be measured from the lowest connection of a branch vent to the termination outdoors.
CPC § 1014.3.6 High relevance — show source text
Rounded up to nominal interceptor volume. 3 Where the flow rate of directly connected fixture(s) or appliance(s) have no assigned DFU values, the additional grease interceptor volume shall be based on the known flow rate (gpm) (L/s) multiplied by 30 minutes.

EXAMPLE 1014.3.6

GRAVITY GREASE INTERCEPTOR SIZING EXAMPLE

Given: A restaurant with the following fixtures and equip ment.

One food preparation sink; three-floor drains - one in the food prep area, one in the grill area, and one receiving the indirect waste from the ice machine and a mop sink.

Kitchen Drain Line DFU Count (from Table 702.1):

3 floor drains at 2 DFUs each = 6 DFUs

Mop sink at 3 DFUs each = 3 DFUs

Food prep sink at 3 DFUs each = 3 DFUs

Total = 12 DFUs

Using Table 1014.3.6, the grease interceptor will be sized at 750 gallons (2389 L).

1015.0 FOG (Fats, Oils, and Greases) Disposal Sys- tem.

1015.1 Purpose. The purpose of this section is to provide the necessary criteria for the sizing, application, and installation of FOG disposal systems designated as a pretreatment or discharge water quality compliance strategy.

TABLE 1014.3.6

GRAVITY GREASE INTERCEPTOR SIZING

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TRAPS AND INTERCEPTORS

1015.2 Components, Materials, and Equipment. FOG disposal systems, including components, materials, and equipment necessary for the proper function of the system, shall comply with ASME A112.14.6. 1015.3 Sizing and Installation. FOG disposal systems shall be sized and installed in accordance with the manufac turer’s installation instructions.

1015.4 Performance. FOG disposal systems shall produce an effluent quality not to exceed 5.84 grains per gallon (gr/gal) (100 mg/L) FOG. 1015.5 [OSHPD 1, 1R, 2, 3, 4 & 5] Grease interceptors shall not be installed in food preparation area of kitchens. 1015.6 [OSHPD 1, 1R, 2, 3, 4 & 5] Grease interceptors shall be installed outside of the kitchen area in location affording ease of maintenance and servicing.

1016.0 Sand Interceptors.

1016.1 Discharge. Where the discharge of a fixture or drain contains solids or semi-solids heavier than water that would be harmful to a drainage system or cause a stoppage within the system, the discharge shall be through a sand interceptor. Multiple floor drains shall be permitted to discharge into one sand interceptor. 1016.2 Authority Having Jurisdiction. Sand interceptors are required where the Authority Having Jurisdiction deems it advisable to have a sand interceptor to protect the drainage system. 1016.3 Construction and Size. Sand interceptors shall be built of brick or concrete, prefabricated coated steel, or other watertight material. The interceptor shall have an interior baffle for full separation of the interceptor into two sections.
CPC § 704.1 High relevance — show source text
Inlet, for fixture connections . . . . . . . . . . . .704.1, 704.2

Lead content . . . . . . . . . . . . . . . . . . . . . .604.2, 604.2.1

Material of . . . . . . . . . . . . . . . . . . . .604.0, Table 604.1,

Table 701.2, 701.3, 903.0,

1208.5, 1208.5.9, 1208.5.9.5

Medical gas

and medical vacuum . . . . . .1320.2, 1320.2.1, 1321.1

Plumbing vent . . . . . . . . . . . . . . . . . . . . . . . . . . . .903.0

Prohibited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .310.1

Screwed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .310.8

Water supply system . . . . . . . . . . . .604.0, Table 604.1,

605.0, A 107.3

FIXTURE . . . . . . . . . . . . . . . . . . . . .(see Plumbing fixtures)

Branch, definition . . . . . . . . . . . . . . . . . . . . . . . . .208.0

Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . .422.1.1

Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . .704.0

Drain, definition . . . . . . . . . . . . . . . . . . . . . . . . . . .208.0

Flanged connection . . . . . . . . . . . . . . . . . . . . . . . .402.6

Future installations . . . . . . . . . . . . . . . . . . . . . . . .402.11

Plumbing . . . . . . . . . . . . . . . . . . (see Plumbing fixtures) Units, drainage (DFU) . . . . . . . . . . . 702.1, Table 702.1,

C 303.1, Table C 303.3

Units, water supply (WSFU) . . . . . . . 610.3, Table 610.3,

610.10, Table 610.10,

A 103.1, Table A 103.1,

C 303.1, Table C 303.2

FLAGPOLING OF VENTS . . . . . . . . . . . . . . . . . . . . . .906.3

FLAMMABLE VAPOR OR FUMES . . . . . . . . . . .208.0, 507.12

FLASHING . . . . . . . . . . . . . . . . . . . . . . . . .701.5, 906.5, 906.6,
CPC § 704.0 High relevance — show source text
Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . .704.0

Drain, definition . . . . . . . . . . . . . . . . . . . . . . . . . . .208.0

Flanged connection . . . . . . . . . . . . . . . . . . . . . . . .402.6

Future installations . . . . . . . . . . . . . . . . . . . . . . . .402.11

Plumbing . . . . . . . . . . . . . . . . . . (see Plumbing fixtures) Units, drainage (DFU) . . . . . . . . . . . 702.1, Table 702.1,

C 303.1, Table C 303.3

Units, water supply (WSFU) . . . . . . . 610.3, Table 610.3,

610.10, Table 610.10,

A 103.1, Table A 103.1,

C 303.1, Table C 303.2

FLAGPOLING OF VENTS . . . . . . . . . . . . . . . . . . . . . .906.3

FLAMMABLE VAPOR OR FUMES . . . . . . . . . . .208.0, 507.12

FLASHING . . . . . . . . . . . . . . . . . . . . . . . . .701.5, 906.5, 906.6,

1102.3, K 103.1.1

FLOOD RESISTANT CONSTRUCTION

Coastal high hazard area . . . . . . . . . . . . .205.0, 301.4.1

Design flood elevation . . . . . . . . . . . . . . . . . . . . . .206.0

Flood hazard area . . . . . . . . . . . . . . . . . . . . . . . . .208.0

Flood hazard resistance . . . . . . . . . . . . . . . . . . . . .301.4

FLOOD-LEVEL RIM . . . . . . . . . . . . . . . . . . . .208.0, 801.3.2

FLOODED, DEFINITION . . . . . . . . . . . . . . . . . . . . . . .208.0

FLOOR DRAINS . . . . . . . . . . . . . . . . . . . . . . . . . . . . .418.0

Connected into a trap . . . . . . . . . . . . . . .1006.1, 1007.1

Directly connected to

drainage system . . . . . . . . . . . . . . . . . . . . . . . .1007.1

Location . . . . . . . . . . . . . . . . . . . . .418.3, 418.4, 1017.1

Required . . . . . . . . . . . . . . .408.8, 704.3, 1017.1, E 501.6
CPC § 601.8 High relevance — show source text
C 601.8 Prohibited Connections Near Base of Stack. Where stacks are more than 75 feet (22 860 mm) high, a separate stack shall be provided for the fixtures on the lower two stories. The stack for the lower two stories shall be permitted to be connected to the branch of the building drain that serves the stack for the upper stories at a point that is not less than 8 feet (2438 mm) downstream from the base of the upper stack. Where stacks are less than 75 feet (22 860 mm) high but more than two stories high, the lowest story shall not connect within 8 feet (2438 mm) downstream from the base of the stack. Venting for the lowest story shall be provided in accordance with Section C 601.8.1 and Section C 601.8.2.

C 601.8.1 Conditional Vent. Venting of fixtures on the lowest floor shall be in accordance with Section 908.0 through Section 911.5 and may connect into the single-stack as a conditional vent. The conditional vent connects into the stack by means of a wye-fitting to prevent ingress of drainage into the vent. No more than 12 drainage fixture units (DFU) may be connected into the conditional vent and shall connect not less than 8 feet (2438 mm) above the stack base.

C 601.8.2 Other Branch Vent. Other branch vents shall be vented in accordance with Section 908.0 through Section 911.5.

C 601.9 Sizing Building Drains and Sewers. In a single-stack vent system, the building drain and branches thereof shall be sized in accordance with Table 703.2, and the building sewer shall be sized in accordance with Table 717.1. C 601.10 Parallel Vent Stacks. Drainage stacks extending more than 75 feet (22 860 mm) shall be provided with a parallel vent stack and shall meet the requirements of Section 907.0.

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CALIFORNIA PLUMBING CODE – MATRIX ADOPTION TABLE

APPENDIX D - SIZING STORM WATER DRAINAGE SYSTEMS

(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 § 1014.3.7 High relevance — show source text

1014.3.7 Abandoned Gravity Grease Intercep- tors. Abandoned grease interceptors shall be pumped and filled as required for abandoned sewers and sewage disposal facilities in Section 722.0.

DRAINAGE FIXTURE UNITS1, 3 (DFUs)	INTERCEPTOR VOLUME2 (gallons)
8	500
21	750
35	1000
90	1250
172	1500
216	2000
307	2500
342	3000
428	4000
576	5000
720	7500
2112	10 000
2640	15 000

For SI units: 1 gallon = 3.785 L

Notes: 1 The maximum allowable DFUs plumbed to the kitchen drain lines that will be connected to the grease interceptor. 2 This size is based on DFUs, the pipe size from this code; Table 703.2; Useful Tables for flow in half-full pipes (ref: Mohinder Nayyar Piping Handbook, 3rd Edition, 1992). Based on 30-minute retention time (ref.: George Tchobanoglous and Metcalf & Eddy. Wastewater Engineering Treatment, Disposal, and Reuse, 3rd Ed. 1991 & Ronald Crites and George Tchobanoglous. Small and Decentralized Wastewater Management Systems, 1998). Rounded up to nominal interceptor volume. 3 Where the flow rate of directly connected fixture(s) or appliance(s) have no assigned DFU values, the additional grease interceptor volume shall be based on the known flow rate (gpm) (L/s) multiplied by 30 minutes.

EXAMPLE 1014.3.6

GRAVITY GREASE INTERCEPTOR SIZING EXAMPLE

Given: A restaurant with the following fixtures and equip ment.

One food preparation sink; three-floor drains - one in the food prep area, one in the grill area, and one receiving the indirect waste from the ice machine and a mop sink.

Kitchen Drain Line DFU Count (from Table 702.1):

3 floor drains at 2 DFUs each = 6 DFUs

Mop sink at 3 DFUs each = 3 DFUs

Food prep sink at 3 DFUs each = 3 DFUs

Total = 12 DFUs

Using Table 1014.3.6, the grease interceptor will be sized at 750 gallons (2389 L).

1015.0 FOG (Fats, Oils, and Greases) Disposal Sys- tem.

1015.1 Purpose. The purpose of this section is to provide the necessary criteria for the sizing, application, and installation of FOG disposal systems designated as a pretreatment or discharge water quality compliance strategy.

TABLE 1014.3.6

GRAVITY GREASE INTERCEPTOR SIZING

2025 CALIFORNIA PLUMBING CODE 199

TRAPS AND INTERCEPTORS

CPC § 304.8 High relevance — show source text

600| |1500|208|416|751|1300|1960|3530|9760|18 900| |1600|201|402|725|1260|1900|3410|9430|18 200| |1700|194|389|702|1220|1840|3300|9130|17 600| |1800|188|377|680|1180|1780|3200|8850|17 100| |1900|183|366|661|1140|1730|3110|8590|16 600| |2000|178|356|643|1110|1680|3020|8360|16 200|

For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 pound-force per square inch = 6.8947 kPa

Table entries are rounded to 3 significant digits.

330 2025 CALIFORNIA MECHANICAL CODE

FUEL GAS PIPING

TABLE 1315.2(36) POLYETHYLENE PLASTIC TUBING [NFPA 54: TABLE 6.3.1(m)] [2]

Col1	GAS:	UNDILUTED PROPANE
	INLET PRESSURE:	11.0 in. w.c.
	PRESSURE DROP:	0.5 in. w.c.
	SPECIFIC GRAVITY:	1.50
INTENDED USE: SIZING BETWEEN INTEGRAL 2-STAGE REGULATOR AT TANK OR SECOND-STAGE (LOW PRESSURE REGULATOR) AND THE BUILDING	INTENDED USE: SIZING BETWEEN INTEGRAL 2-STAGE REGULATOR AT TANK OR SECOND-STAGE (LOW PRESSURE REGULATOR) AND THE BUILDING	INTENDED USE: SIZING BETWEEN INTEGRAL 2-STAGE REGULATOR AT TANK OR SECOND-STAGE (LOW PRESSURE REGULATOR) AND THE BUILDING
	PLASTIC TUBING SIZE (CTS)1 (inch)	PLASTIC TUBING SIZE (CTS)1 (inch)
NOMINAL OD:	1⁄2	1
DESIGNATION:	SDR 7	SDR 11
ACTUAL ID:	0.445	**0.

CPC § 2.2 High relevance — show source text

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*

For SI Units: 1 inch = 25 mm

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

TABLE 702.2

DISCHARGE CAPACITY IN GALLONS PER MINUTE FOR

INTERMITTENT FLOW ONLY*

GPM	FIXTURE UNITS
Up to 71⁄2	Equals 1 Fixture Unit
Greater than 71⁄2 to 15	Equals 2 Fixture Units
Greater than 15 to 30	Equals 4 Fixture Units
Greater than 30 to 50	Equals 6 Fixture Units

For SI units: 1 gallon per minute = 0.06 L/s

Discharge capacity exceeding 50 gallons per minute (3.15 L/s) shall be determined by the Authority Having Jurisdiction.

702.3 Continuous Flow. For a continuous flow into a drainage system, such as from a pump, sump ejector, air conditioning equipment, or similar device, 2 fixture units shall be equal to each gallon per minute (gpm) (L/s) of flow.

703.0 Size of Drainage Piping. 703.1 Minimum Size. The minimum sizes of vertical, horizontal, or both drainage piping shall be determined from the total of fixture units connected thereto, and additionally, in the case of vertical drainage pipes, in accordance with their length.

703.2 Maximum Number of Fixture Units. Table 703.2

shows the maximum number of fixture units allowed on a vertical or horizontal drainage pipe, building drain, or building sewer of a given size; the maximum number of fixture units allowed on a branch interval of a given size; and the maximum length (in feet and meters) of a vertical drainage pipe of a given size. 703.3 Sizing per Appendix C. For alternate method of sizing drainage piping, see Appendix C.

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.

TABLE 702.1(1) MAXIMUM DRAINAGE FIXTURE UNITS FOR A

TRAP AND TRAP ARM*

CPC § 907.2 High relevance — show source text
907.2 Yoke Vent. The yoke vent connection to the vent stack shall be placed not less than 42 inches (1067 mm) above the floor level, and the yoke vent connection to the drainage stack shall be using a wye-branch fitting placed below the lowest drainage branch connection serving that floor.

908.0 Wet Venting. 908.1 Vertical Wet Venting. Wet venting is limited to vertical drainage piping receiving the discharge from the trap arm of one and two fixture unit fixtures that also serves as a vent not exceeding four fixtures. Wet-vented fixtures shall be within the same story; provided, further, that fixtures with a continuous vent discharging into a wet vent shall be within the same story as the wet-vented fixtures. No wet vent shall exceed 6 feet (1829 mm) in developed length. 908.1.1 Size. The vertical piping between two consecutive inlet levels shall be considered a wet-vented sec tion. Each wet-vented section shall be not less than one pipe size exceeding the required minimum waste pipe size of the upper fixture or shall be one pipe size exceeding the required minimum pipe size for the sum of the fixture units served by such wet-vented section, whichever is larger, but in no case less than 2 inches (50 mm) in diameter. 908.1.2 Vent Connection. Common vent sizing shall be the sum of the fixture units served but, in no case,

190 2025 CALIFORNIA PLUMBING CODE

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

VENTS

smaller than the minimum vent pipe size required for a fixture served, or by Section 904.0. 908.2 Horizontal Wet Venting for a Bathroom Group. A bathroom group located on the same floor level shall be permitted to be vented by a horizontal wet vent where all of the conditions of Section 908.2.1 through Section 908.2.5 are met.

908.2.1 Vent Connection. The dry vent connection to the wet vent shall be an individual vent for the bidet, shower, or bathtub. One or two vented lavatory(s) shall be permitted to serve as a wet vent for a bathroom group. Only one wet-vented fixture drain or trap arm shall discharge upstream of the dry-vented fixture drain connection. Dry vent connections to the horizontal wet vent shall be in accordance with Section 905.2 and Section

905.3.

908.2.2 Size. The wet vent shall be sized based on the fixture unit discharge into the wet vent. The wet vent shall be not less than 2 inches (50 mm) in diameter for 4 drainage fixture units (dfu) or less, and not less than 3 inches (80 mm) in diameter for 5 dfu or more. The dry vent shall be sized in accordance with Table 702.1 and Table 703.2 based on the total fixture units discharging into the wet vent.

908.2.3 Trap Arm. The length of the trap arm shall not exceed the limits in Table 1002.2. The trap size shall be in accordance with Section 1003.3. The vent pipe opening from the horizontal wet vent, except for water closets and similar fixtures, shall not be below the weir of the trap.

Frequently asked questions

What exactly is a DFU and where do I find the values?

A DFU is a numeric unit assigned to fixture types for sanitary drainage and vent sizing; the values are listed in Table 702.1 of the CPC and referenced from § 702.1.

How do I size a vent using DFUs?

Total the DFUs for the branch/interval, then use the vent‑sizing rules/tables (which require the DFU total and developed length). The DFUs come from Table 702.1; vent developed‑length rules are in the vent sizing sections/appendices.

My pump discharges at 10 gpm — how many DFUs is that?

If it’s intermittent flow use Table 702.2: >7½–15 gpm = 2 DFU. If the flow is continuous, use § 702.3: 2 DFU = 1 gpm of continuous flow.

Can I increase trap size to accept more DFUs?

No — don’t exceed the maximum DFU permitted for the trap/trap arm size in Table 702.1(1). The code warns against increasing trap size to a point that reduces self‑scouring.

Where can I find a ready example that does the math?

The CPC includes an example for grease‑interceptor sizing that totals DFUs from Table 702.1 and uses that total to select an interceptor — see the kitchen example in the CPC text.

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Related in the CPC

Maximum unit loading and maximum length limits for drainage and vent piping

Fixture connections — inlet fittings and single-vertical drainage conditions

System sizing & fixture units

California Plumbing Code

How to size drains and vents using drainage fixture units (DFU)

What the code requires — 2-4 sentences

Requirements in detail

1) Defined term and where it appears

2) Assign DFU values (what to look up)

3) Trap / trap arm limits

4) Intermittent and continuous flow rules

5) From DFU totals to pipe/vent sizes

At-a-glance trap-size limits (from Table 702.1(1))

Exceptions & special cases

Common mistakes

Worked example — small commercial kitchen (numbers)

Related provisions

Code references

Frequently asked questions

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