How to Size a Fountain Pump


Read your manual for installation, operation, and safety information. This guide neither supplements nor replaces the Owner’s Manual.

How to Size a Fountain Pump
There is more to choosing a fountain pump than just by physical size. The most obvious way to choose the right size pump for your fountain is to look at the size of the basin it will be sitting in. If you're creating a small table top fountain, you will choose a very small fountain pump that can be tucked away underneath some decorative river stones. Conversely, if you are installing a large fountain feature in your backyard that holds many gallons of water, a much larger sized pump is needed. To ensure you have selected the correct fountain pump for your needs, there are certain pump ratings that you must consider in addition to the pump's physical size.

Step One - Check the GPH (gallons per hour) rating
This is how many gallons of water the pump can circulate in one hour. Measure the diameter of the hole at the top of your fountain feature and do a little math. In most cases, for every inch of diameter, the pump will need to supply 100 gallons of water per hour.

Step Two - Look for the maximum head height rating
This is how high (vertically) the pump can lift the water. Water pumped to its maximum height by a given pump doesn't necessarily mean the flow will be very strong at that maximum height. In fact, it might be only a trickle. Therefore, choose a pump whose maximum height is higher than the height at which the water emerges from your fountain feature to ensure a strong stream of water. A discharge flow reducer (valve) can be used to adjust the flow to your needs.

Step Three - Check the discharge size of the pump
The pump discharge diameter affects the volume of water that can be delivered to the fountain feature, as well as the GPH. Check the inlet hole in the fountain feature to determine the inside diameter of the tubing you will need to connect the pump to the fountain feature. This information should be clearly shown on the fountain feature packaging. Purchase the pump that offers the discharge size that corresponds with the tubing you will be using. Unless the discharge diameter is the same as the tubing inside diameter, the volume of water the pump is rated for may not be delivered.