Sizing a Pump for Your Waterfall


Not sure how to properly size your waterfall pump? Feel free to check out our online calculators

There are several factors that go into getting the right size pump for your waterfall.  First you need to decide on your waterfall flow rate.

Waterfall Flow Rate 

The waterfall flow rate is how much water is flowing over a waterfall or stream to achieve the desired effect.  The more water that flows over the waterfall the louder the sound of running water will be. Here are some guidelines to help you determine the waterfall flow rate based on the amount of flow you desire.

·         Light Flow = 100 gallons per hour (gph) per inch of spillway

·         Medium Flow = 150 gph per inch of spillway

·         High Flow = 200 gph per inch of spillway

Width of Spillway X Desired Flow Rate = Total GPH 

Width of Spillway

EXAMPLE: You want your waterfall to have a 24” spillway


                Light Flow = 24” Spillway x 100 gph = 2,400 gph

                Medium Flow = 24” Spillway x 150 gph = 3,600 gph

                Heavy Flow = 24” Spillway x 200 gph = 4,800 gph

You will need a pump that will be able to pump this much water at the height of the waterfall after it overcomes the head pressure.

Sizing a Pump for Your Waterfall

To determine the size pump you will need for your waterfall, you will need to know the waterfall flow rate, the length of tubing, the height of the waterfall, and the number of elbow & T fittings used.

Sizing a Pump for your waterfall formula


EXAMPLE:  Your waterfall is 24” wide and requires 3,600 gph and is 4’ above ground level and has 10’ of tubing and 2 elbow fittings.

ANSWER:  4’ high + 1’ for tubing + 2’ for fittings = 7’ of head

You will need a pump that provides 3,600 gph at 7’ of head to achieve the desired effect of the waterfall or stream.

For more information: proper pump selection