Water Supply

UPC WSFU & Drainage Table

UPC Table 703.2 fixture unit values for both water supply (WSFU) and drainage (DFU) sizing.

Introduction

The UPC Table 703.2 provides maximum unit loading and maximum length for drainage and vent piping. It also defines WSFU values for water supply sizing. These values differ from IPC values.

UPC Table 703.2 - Maximum Unit Loading and Maximum Length

Pipe Size (in)	Max DFU Vertical	Max DFU Horizontal	Max Length Vertical (ft)	Max DFU Vent	Max Length Vent (ft)
1-1/4	1	1	45	1	45
1-1/2	2	1	65	8	60
2	16	8	85	24	120
3	48	35	212	84	212
4	256	216	300	256	300
5	600	428	390	600	390
6	1380	720	510	1380	510
8	3600	2640	750	3600	750
10	5600	4680	-	-	-
12	8400	8200	-	-	-

UPC Appendix C Table C304.3 - Horizontal Fixture Branches and Stacks

Pipe Size (in)	Horizontal Branch	One Stack (<=3 Branch Intervals)	Stack (>3 Intervals) Total	Stack (>3) One Interval
1-1/2	3	4	8	2
2	6	10	24	6
2-1/2	12	20	42	9
3	20	48	72	20
4	160	240	500	90
5	360	540	1100	200
6	620	960	1900	350
8	1400	2200	3600	600
10	2500	3800	5600	1000
12	3900	6000	8400	1500

Notes

• For 1/8" per foot slope, multiply horizontal DFU values by 0.8.
• UPC values differ from IPC values for the same pipe sizes.
• Vent pipe sizing uses the same table with separate columns.

UPC Pipe Sizing Guide

How the Uniform Plumbing Code sizes water supply pipes using WSFU tables, and how Plumbing Booster applies UPC-specific values for both water supply and drainage.

Drainage Pipe Sizing Reference

Complete reference for drainage pipe sizing using IPC Table 710.1 and UPC Table 703.2, including slope requirements and maximum length limitations.