704.3 Commercial Sinks — 2025 California Plumbing Code
California Plumbing Code (Title 24, Part 5) · 2025 edition · updated 2026-09-25 · California
CBSC: official editions, supplements and errata
Italicized text is a California amendment to the model code, as printed in the official publication.
Cite as: 2025 California Plumbing Code (Title 24, Part 5) § 704.3 · Effective January 1, 2026 · Official source: Building Standards Commission
Pot sinks, scullery sinks, dishwashing sinks, silverware sinks, and other similar fixtures shall be connected directly to the drainage system. A floor drain shall be provided adjacent to the fixture and shall be connected on the sewer side of the sink. No other drainage
168 2025 CALIFORNIA PLUMBING CODE
SANITARY DRAINAGE
TABLE 703.2
MAXIMUM UNIT LOADING AND MAXIMUM LENGTH OF DRAINAGE AND VENT PIPING
| SIZE OF PIPE (inches) | 11⁄4 | 11⁄2 | 2 | 3 | 4 | 5 | 6 | 8 | 10 | 12 |
|---|---|---|---|---|---|---|---|---|---|---|
| Maximum Units Drainage Piping1 Vertical Horizontal |
1 1 |
22, 7 17 |
163 83 |
484 354 |
256 2165 |
600 4285 |
1380 7205 |
3600 26405 |
5600 46805 |
8400 82005 |
| Maximum Length Drainage Piping Vertical, (feet) Horizontal (unlimited) |
45 |
65 |
85 |
212 |
300 |
390 |
510 |
750 |
– |
– |
| Vent Piping Horizontal and Vertical6 Maximum Units Maximum Lengths, (feet) |
1 45 |
83 60 |
24 120 |
84 212 |
256 300 |
600 390 |
1380 510 |
3600 750 |
– |
– |
For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm
Notes: 1 Excluding trap arm. 2 Except for sinks, urinals, and dishwashers – exceeding 1 fixture unit. 3 Except for six-unit traps or water closets. 4 Not to exceed six water closets or five six-unit traps. 5 Based on 1 ⁄ 4 inch per foot (20.8 mm/m) slope. For 1 ⁄ 8 of an inch per foot (10.4 mm/m) slope, multiply horizontal fixture units by a factor of 0.8. 6 The diameter of an individual vent shall be not less than 1 1 ⁄ 4 inches (32 mm) nor less than one-half the diameter of the drain to which it is connected. Fixture unit load values for drainage and vent piping shall be computed from Table 702.1 and Table 702.2. Not to exceed one-third of the total permitted length of a vent shall be permitted to be installed in a horizontal position. Where vents are increased one pipe size for their entire length, the maximum length limitations specified in this table do not apply. This table is in accordance with the requirements of Section 901.3. 7 Up to 8 public lavatories are permitted to be installed on a 1 1 ⁄ 2 inch (40 mm) vertical branch or horizontal sanitary branch sloped at 1 ⁄ 4 inch per foot (20.8 mm/m).
line shall be connected between the floor drain waste con nection and the fixture drain. The fixture and floor drain shall be trapped and vented in accordance with this code.
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