Drain Size Calculator | SJ AI Studio

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Total DFU: 0

DFU to Drain Size Reference (UPC / IPC)

Max DFU	Horizontal Drain	Vertical Stack
1	1-1/4"	1-1/4"
3	1-1/2"	1-1/2"
6	2"	2"
12	2-1/2"	2-1/2"
20	3"	3"
160	4"	4"
360	5"	5"
620	6"	6"

Note: Any branch carrying a toilet (water closet) requires a minimum 3" drain. Slope for horizontal drains: 1/4" per foot for pipes 3" and smaller, 1/8" per foot for 4" and larger.