717.1 General — 2025 California Plumbing Code

The minimum size of a building sewer shall be determined on the basis of the total number of fixture units drained by such sewer, in accordance with Table 717.1. No building sewer shall be smaller than the building drain.

For alternate methods of sizing building sewers, see Appendix C.

TABLE 717.1

MAXIMUM/MINIMUM FIXTURE UNIT LOADING

For SI units: 1 inch = 25 mm, 1 inch per foot = 83.3 mm/m

• See also Appendix H, Private Sewage Disposal Systems. For alternate methods of sizing drainage piping, see Appendix C.