Waterfall Pumps

Figuring out the correct pump size you need is worth the time and effort. If the pump is too small, there may be no waterfall because the pump wasn’t strong enough. If the pump is too large, there may be too much pressure for the size of the waterfall and water will gush over the sides instead of out of the spillway, creating a mess.

Determining the flow and lift needed is a two-phase formula.

To determine the flow, use this rule of thumb. For every 1 in. of spillway width, you need 100 GPH (gallons per hour) flow to achieve a “sheet” look. Divide by two for a “trickle” look. Multiply by two for a “Niagara” look.  

TIP! Check the pump’s specifications for the ideal pumping height at the head of your waterfall.  

TIP! Excessive bending or the addition of in-line filters will reduce the flow.  

To determine at what height (or lift) you need that flow, factor in the length the pump will need to push water.  

1. Measure the distance the pump will be in your pond up to the waterfall spillway. This measurement is your length and also the length of tubing needed. For every 10 ft. in horizontal length, add one foot of lift to your calculation.
2. Measure the height from the TOP of the pond water (don't measure the depth of the pond, only from the surface of the pond) to the top of the waterfall spillway. For every foot of height, the water must be pushed from the top of the pond water, we calculate one foot of height.  
3. Add up the heights (or lifts).  

Example: The pump is 30 ft. from the spillway, so we divide 30 ft. of horizontal length by 10 ft. to get 3 ft. of lift. Your waterfall spillway is 4 ft. from the top of the pond water. So, 3 ft. lift in length plus 4 ft. lift in height gives us a total of 7 ft. of lift.