Hydroponic pumps are the lifeline of most hydroponic systems. Powerful pumps move the nutrient solution from the reservoir to your plant roots. Hydroponic water pumps need to battle head height when moving water vertically. Inline pumps are outside the reservoir while submersible water pumps are inside the reservoir.

Keep reading to learn all you need to know about hydroponic pumps!

What you should know about water pumps for Hydroponics

When you grow hydroponic plants, it’s important to have a water pump. Hydroponic water pumps keep the water in motion and pass nutrients through your plants’ roots.

You don’t need to buy a water pump specific to your hydroponic system, for the most part. Fountain or aquarium pumps do just fine. 

The important things to pay attention to are the GPH rating and the wattage on your pump. Higher wattage means a stronger pump. 


GHP stands for gallons per hour. It illustrates how many gallons the pump moves in an hour. 

How many GPH do you need?

Each kind of hydroponic system will feed plants a little differently. For example, a drip system with a 25 gallon reservoir doesn’t need to circulate water at the same frequency as an NFT system with the same sized reservoir. 

If you’re unsure how much nutrient solution needs to be circulating, a good rule of thumb is to try to get a full circulation every two hours. 

This means having the entire reservoir move throughout your system in about two hours.

Let’s go over an example of how to size a hydroponic water pump based on GPH.

If you have a 50 gallon reservoir, and you want it to circulate each two hours, just divide 50 by 2. Simply put, you want to pump 25 gallons/hour in order to pump 50 gallons in two hours.

Ebb and flow systems are measured slightly differently because you aren’t circulating the nutrient solution constantly. 

First figure out how long your flood intervals are. Now measure the height of the water level you want.

If you need 5 gallons and want it to reach the fill line in 10 minutes, divide 5 by 10 to get 1/2. Then translate gallons per minute into gallons per hour by calculating 1/2 GPM x 60 minutes/hour= 30 GPH. 

Head Height

The higher the hydroponic pump needs to pump the water vertically, the more pressure is put on the pump due to gravity and water. When there’s more pressure put onto the pump than the pump is able to put out, that’s called its Max Head Height.

It’s vital to consider how high the water line is when choosing a water pump for hydroponic systems. Head height can drastically change the actual GPH that your pump is able to produce. You can usually find a chart that correlates GPH and head height on the packaging of the pump you’re buying.

Search for pumps that have the highest head height within your budget.

How are hydroponic pumps rated or sized?

There are three main ways that hydroponic pumps are rated and sized: GPH, PSI, and HP.

GPH stands for gallons per hour. It describes how many gallons of nutrient-rich solution your pump is able to move in a given hour.

PSI stands for pounds per square inch. Lots of pumps don’t advertise their PSI unless they’re for high pressure, traditional systems.

HP stands for horsepower. HP is mostly relevant for inline pumps, or pumps that are outside of the tank. Pumps that are rated in HP are typically reserved for larger grow operations. Eventually the GPH rating gets so big that it’s easier to just convert it into HP.

Types of hydroponic pumps

There are two main types of hydroponic pumps: inline water pumps and submersible pumps.

Inline pumps

Inline pumps live outside of your reservoir. Never put them underwater. These pumps are connected outside the tank and they have a motor in a separate encasement. 

Hydroponic setups that have more than 1,000 gallons of water benefit from inline pumps.

Because of how strong they are, they’re typically reserved for commercial growers. 

Submersible pumps

Submersible pumps are inside the reservoir. Nutrient solution gets transported to the growing tray this way. 99% of non-commercial hydroponic gardeners use submersible water pumps.

Which pump type to choose?

If you’re a hobbyist with a small-scale operation, you’ll likely want a submersible pump.

If you’re a full-scale grow operation, inline pumps are for you.

How to pick the right size?

There are three steps to picking the rights size hydroponic pump.

1. Calculate your GPH. 

When you begin to look at hydroponic pumps, you’ll notice that they all have a GPH on the label. This is how many gallons your pump will move per hour. Make sure the reading isn’t in metric.

GPH is the flow rate times the number of units per that flow rate.

2. Measure your head height.

Almost all hydroponic systems have growing mediums and plants higher than the reservoir is situated. Because of this, the water will have to make a vertical trip.

Head height is considered the level of water that’s in your tank compared to the bottom of your reservoir. All you have to do is measure it.

Just remember that water levels do drop, so be sure that these lowered head heights will still cover the pump you choose.

3. Combine your GPH and head height.

You want to get the pump with the highest head height within your budget. Don’t go based on the advertised GPH because it will reduce with head height.

Hydroponic pumps with high PSI’s can almost always overcome back pressure. 

Choosing the right flow rate

Considering elevation and back pressure, you need to figure out how many GPH your pump needs, what your budget is, and what head height you have. The majority of hydroponic pumps lose up to 30% efficiency when everything is accounted for.

Many people go as far as to double the GPH they need when they buy a water pump. 

Something else to bear in mind is that lots of pumps are sold with a GPH range instead of a specific GPH. If there’s a range listed, that’s likely because it includes flow adapters.

How to adjust flow rate?

There are a few steps to adjust the flow rate.

To begin, acquire a bit of extra tubing as well as a T connector.

Attach the connector to the tubing that connects your grow tray and your pump. Attach other pieces of tubing to each end of the T.

One of these tubes will go to your plants, and the other will go into your reservoir. Since the nutrient solution is now going in multiple directions, the flow rate decreases.

However, if this method doesn’t work, you can install a valve between the tubing and the connector. This can let you even further adjust the flow rate.


What if my water pump is clogged?

Sometimes pumps stop working or start to make a lot of noise. This is because debris or nutrient solution may be choking your pump.

If this happens, you need to remove your pump in order to clean it. 

Even if your pump isn’t running into any problems, it’s important to clean your pump every once in a while. Once a month will suffice.

In addition, you can prevent clogs ahead of time with a pre-filter, as long as it’s compatible with your pump. You can also just put your pump in a mesh bag.

My water pump is causing lots of noise. How to reduce it?

 One thing to keep in mind is that all pumps make noise, so noise isn’t necessarily a bad thing.

If noise really bothers you, you can get a submersible pump instead of an inline pump. They tend to be less noisy. You can also be mindful of where you put your setup in your home. For example, if you have an office, you may not want it in the same room.

You can wrap a sponge scrubber pad around the pump. This tends to lower the noise but it can make your pump die out sooner. You can also put a sound dampening pad beneath your pump. 

How often do I need to run the water pump?

There is no steadfast answer as to how often you need to run the hydroponic water pump. It depends on what kind of hydroponic system you’re using and what plants you’re growing.

Another factor is what growing medium you’re using. This is because if you’re using a medium that holds onto water very well, such as coco coir. you won’t need to run the pump as often. Meanwhile, mediums like perlite will require you to run your pump more.

When do you need a hydroponic water pump?

Some systems don’t need a hydroponic pump at all, such as wicking or deep water culture. But for ebb and flow, aeroponics, aquaponics, and more, you definitely need a pump.

Pumps are vital to these systems because they move the water around and provide nutrients to your plants.

Air pumps and water pumps are different. Air pumps aerate the water while water pumps move the water around. Don’t confuse the two!

When plant roots aren’t in constant contact with water like they are in DWC, that’s when you need a water pump. 

Can you use a pool pump for hydroponics?

Pool pumps also use a lot of electricity to run. While they may be cheaper when you first buy them, they’re more expensive in the long run due to their extensive electricity usage.

Pool pumps don’t do well in hydroponic setups. They use high flow and high pressure when compared to typical hydroponic pumps.


Almost no hydroponic system would be complete without its hydroponic pump. Without the pump there would be no way for plants to get the nutrients they need to survive and thrive. 

Now that you have a baseline knowledge about hydroponic pumps, check out the rest of our blog for growing tips and more!