703.2 Maximum Number of Fixture Units — 2025 California Plumbing Code

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. TABLE 703.2

MAXIMUM UNIT LOADING AND MAXIMUM LENGTH OF DRAINAGE AND VENT PIPING

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).