What is the flow rate for 2 inch pipe?

For water supply: Copper = 55.4 GPM, PEX = 54.1 GPM at 6 ft/s velocity. For drainage (PVC): 60.4 GPM capacity, though actual flow is gravity-driven and typically 2-5 GPM for residential applications.

Is 2 inch pipe required for shower drains?

Yes, most codes require minimum 2" pipe for shower and bathtub drains. This ensures adequate flow capacity and prevents clogs. Use our Drainage Slope Calculator to determine proper slope for 2" drain lines.

Can 2 inch pipe be used for water supply?

Yes, 2" pipe is commonly used for commercial water supply applications where high flow capacity is needed. For residential applications, 2" is typically overkill unless serving very large homes or multiple units.

What's the minimum slope for 2 inch drain pipe?

Minimum slope for 2" drain pipe is 1/4" per foot (2% grade) per IPC/UPC codes. This provides self-cleaning velocity. Use our Drainage Slope Calculator to determine exact slope requirements for your installation.

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2 inch pipe calculator

two inch pipe calculator

2 inch pipe flow rate

2 Inch Pipe Calculator & Complete Guide

Calculate flow rates, capacity, and sizing for 2 inch pipes. Complete guide to 2" pipe specifications for water supply and drainage applications with flow capacity data.

PlumberCalc Team

Updated 1/24/2026

2 inch pipe serves dual purposes in plumbing systems: as a larger water supply line for commercial applications and as a standard size for drainage and waste systems. Understanding 2" pipe flow capacity and drainage applications is essential for both water supply and DWV system design.

Key Characteristics

Nominal Size

Inside Diameter

1.935" - 2.067" (varies by material)

2" Pipe Flow Capacity by Material

Maximum recommended flow rates (GPM) for 2" pipe. Note: For drainage applications, flow is gravity-driven and typically lower than pressure systems.

Material	Inside Diameter	C-Value	Max Flow @ 6 ft/s (GPM)	Primary Use
Copper (Type L)	1.985"	140	55.4	Commercial water supply
PEX	1.935"	150	54.1	Large flexible supply
PVC (Drainage)	2.067"	150	60.4	Shower/tub drains, DWV

Frequently Asked Questions

Code Compliance

2" pipe is approved for both water supply and drainage per IPC and UPC codes. Minimum size for shower/tub drains is 2" per most codes. Always verify local code requirements for your specific application.