When looking to DIY or install a water feature in your backyard, you may be wondering how to choose the correct pump size for your project. When I installed my first water feature, I really struggled to find the right pump for the project. The numbers were really confusing and I ended up just choosing one at random and hoping it worked.
But, you don’t have to get bogged down in all of the fountain pump jargon like I did. Today i’ll show you exactly what numbers to pay attention, which to ignore and I’ll also provide simplified explanations for each.
There are several different specs that you need to be aware of in order to choose the correct pump size for your project. Many of the specs displayed prominently on fountain pumps really aren’t very useful in determining if the pump is the right size. So, the ones you need to pay the most attention to are:
- gallons per hour (GPH)
- head height and max height
- lift and max lift
- cord length (this is silly but important!)
I’ll also explain wattage and voltage near the end of this post, but the specs listed above are most useful in determining the right fountain pump size for you. So, let’s uncover in a bit more detail what each of these terms mean.
Gallons per hour (GPH)
Gallons per hour is a measurement to determine the circulation of the water in your fountain. It’s recommended that the water in your fountain should circulate at least one time per hour. So, you just need to determine how many gallons of water your fountain will be. If you are using a pre-made basin this is easy. If your basin holds 20 gallons, you’ll need a pump that says 20GPH (or higher).
Head Height and Max Head
The head height is another measurement you’ll need to know. The head height is the vertical height from the water feature’s water level to your fountain head (where the water spits out). The spec you will see on a fountain pump is not head height though, it’s max head or maximum head. And this is the maximum distance it can push the water straight up.
It’s fairly easy to get this vertical measurement for a simple fountain. However, some fountains are more elaborate so you may need to do a bit more measuring. A good example is when creating a fountain that travels down a river bed into a pond below. You will need to get the vertical height from the water level of the pond to the height of the waterfall. Just measure straight upwards, even if there’s quite a long horizontal distance between the two points.
Next you’ll need to measure the horizontal/diagonal distance (in feet) from directly above the pump all the way to the top of your waterfall (where the water shoots out). This will be pretty close to the amount of tube or pipe you’ll need to carry the water to the top.
Let’s look at an example so this makes more sense. Let’s say that I have a waterfall/river fountain with a vertical distance of 5′ from the top of the pond to the top of the waterfall. My river runs along my lawn at a distance of 20′ total.
First, take the total horizontal/diagonal measurement and divide this number by 10. So you’ll need to divide the 20′ by 10, with gives you 2′.
Next, add this number to your vertical measurement. So in this example we will add add 2′ to the 5′ of vertical distance and we get 7′ head height. Make sense?
In this example, you’ll need to find a pump that has a max head greater than 7 feet.
Lift and Max Lift
Lift is another measurement you’ll need to determine the right fountain pump for you. The lift is the distance (in feet) from your pump to where the water will come out. The difference between lift and head is that for lift we are measuring directly from the pump (even if the pump is under water). For head we measure above the water level.
Once you know the distance the water must travel between your pump and your fountain head, you now know the maximum lift, or max lift, you’ll need. Look for a pump that has a max lift greater than the number you’ve determined.
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Silly thing to discuss, I know. But it’s something I really did not consider at all. Some electric pumps have really long cords. Others have very short cords. So it’s always good to know how long of a cord you’ll need before you purchase.
Of course, the cord length is important for an electric pump, if the water feature will be near your house and you can plug it into an outlet. So, take a quick measurement of this distance. And make sure you’re taking into account that a submersible pump sits at the very bottom of the pond or basin.
If you’ve messed this up and your cord is too short, it’s really not the end of the world. To fix it, you can purchase an outdoor electrical cord (Amazon link) and an outdoor cord cover (Amazon link). The cord cover is a water-tight box that will keep the extension cord and pump connection safe from the elements. Don’t mess around here – you need outdoor rated cords and protective boxes to stay safe.
You may be thinking that if you purchase a solar fountain that cord length does not matter. Well, you’d be wrong, my friend. But don’t feel bad because I made this mistake, too. Just because you are using a solar fountain pump does not mean that your pump is wireless. There will still be a cord going from your pump to the solar panel that’s collecting the energy to run your pump. So, you’ll need to make sure that the length of that cord is long enough for you to place the solar panel in a place where it will receive as much direct sunlight as possible.
The only time that the cord length doesn’t matter much is if your fountain is somewhere out in your yard and you need to hire a contractor to run the electrical underground. In this case the cord length won’t matter too much because they’ll be running different wire and splicing it all together for you. In the case of this type of water feature, voltage becomes more important (see voltage section below for more info)
I hope I just saved you from the headaches I’ve been through with cord length.
Wattage and Voltage
You may see some other specs on your fountain pump and be wondering what these are. The two other common specs you’ll see are wattage (watts) and voltage (volts).
The wattage spec will help you to determine how much energy your pump uses in order to, well, pump. So it’s a great spec for calculating the annual, monthly, weekly or daily cost of running your water feature.
I have a handy fountain electricity cost calculator right here if you are interested in knowing the daily cost of running an electric water feature.
Overall, wattage is not a spec I’d focus on much when choosing the right pump for you.
If the voltage of your pump is not high enough, the pump will end up running on high amps all the time and this can either damage your pump or cause it to stop working.
Typically, your pump is designed to operate at a specific voltage which is determined by the manufacturer. If you are experiencing problems with your pump, often times checking the voltage will help you troubleshoot the issue further. If you’re a beginner, choosing a low voltage pump is safer and the wiring is usually easier to install.
Voltage can be important for larger water features and other types of large pumps. For a standard 120-volt pump, you will have to apply for an electrical permit, bury the wire deep underground and install a GFCI protected outlet. So, this is where the pros will come in.
Overall, for a small backyard water feature, I don’t see voltage as a very important spec to analyze.
Fountain Pump Recommendations
Here are two fountain pumps I’d recommend for a small backyard water feature. The specs for the electric and solar are about equivalent. I’d definitely recommend purchasing the solar pump battery backup if you decide to go solar.
Electric vs. Solar
If you’re looking for some information about the differences between electric and solar pumps, check out this post for a full comparison and video
DIY Fountain Tutorial
If you’re looking for some information on making your own DIY fountain, check out this post: One of the easiest (and coolest) DIY water features.
Some final thoughts on water feature pump size
When choosing a fountain pump, focus on the gallons per hour (GPH), max height, max lift and even the cord length. And, try not to get bogged down too much with the voltage and the wattage, especially if you are purchasing a small pump for a backyard project. I hope this post gave you all of the information and the confidence you need to choose the the right pump for you!
If you’re interested in DIYing your own water feature, you may want to read this post to learn how I made a super cool pondless water feature in less than 1 day. It was a really easy and fun project!
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