Drain, Waste & Vent
Interior drain, waste and vent sizing only: total drainage fixture units (DFU), drain pipe size from DFU, drain slope and fall (fall = length × slope; 1/4 in per foot default), vent pipe size from DFU and developed length, trap-arm length, and drain cleaning / snaking / hydro-jet cost. Sizing follows standard conventions — your local plumbing code and inspector govern.
Planning estimate: this is a planning estimate from the numbers you enter and standard reference quantities — not a bid or a contract. Get itemized written quotes from licensed plumbers and confirm measurements before you commit.
Local plumbing code governs: This sizing follows standard reference conventions (IPC / UPC / NFPA-54-style tables). Your local plumbing code and inspector govern — sizing methods, materials and permit rules vary by jurisdiction. Confirm the design with a licensed plumber and pull the required permit before you build.
Drainage Fixture UnitsAdd up the drainage fixture units (DFU) for your toilets, sinks, tubs, showers and laundry to size the drain and vent with the standard IPC/UPC method.Drain Pipe SizeFind the minimum drain pipe size for your drainage fixture units (DFU) using the standard IPC/UPC sizing band — from a 2 inch branch to a 4 inch drain.Drain Slope & FallWork out the total fall of a drain line from its length and slope. The classic minimum is 1/4 inch per foot for pipe up to 2-1/2 inches across.Vent Pipe SizeSize a plumbing vent from the drainage fixture units it serves and its developed length, using the standard labeled IPC/UPC vent-sizing band.Trap-Arm LengthCheck the maximum trap-arm length from a fixture trap to its vent by pipe diameter, so the trap keeps its water seal and does not siphon dry.Drain Cleaning CostAdd up the line items on your drain-cleaning quote — snaking, hydro-jetting, a camera inspection and the trip fee — to estimate the total you will pay.
Every Drain, Waste & Vent tool is calculated server-side — visible immediately — with its formula, a worked example and a reference table, and works on the prices you enter. Background reading is in the guides.