Choosing the Proper Water Line

This task doesn’t have to be complicated: do not use pipe that is smaller than what is listed for your maximum flow rate!

Example: If you are pumping water from the pond to a waterfall that is 10 feet above the water level of the pond and the pump that you select moves 75 GPM at 10 feet of head, you need to use 2” pipe, or else your flow rate will be nowhere near 75 GPM .

If the length of pipe that you intend to use is longer than 50 feet, you should consult the Friction Loss in Water Pipe page to determine how much a larger pipe size would improve your flow rate. Otherwise, for runs less than 50 feet simply select a size pipe from the table below.


Maximum Recommended Water Flow Rates for Tubing and Flexible PVC Pipe

(Expressed as Pipe Size vs. GPM* and GPH**)

Pipe Size Max GPM* Max GPH**
1/2” 8 480
3/4” 15 900
1” 25 1,500
1-1/4” 45 2,700
1-1/2” 60 3,600
2” 90 5,400
3” 225 13,500
4” 350 21,000
6” 700 42,000

* GPM = Gallons per Minute
** GPH = Gallons per Hour

You can view and purchase Water Line directly from the following link:
Water Line & Plumbing

If you are confused, please email us at for assistance with your project.