Weak or Strong Hydroponic Water Pressure (4 Causes & Tips)

Water pressure can be considered a driver in hydroponic systems. It is the force that delivers the nutrient water towards the plant roots. But what will happen when it becomes too weak or too strong?

Generally, excessively weak or strong hydroponic water pressure results from inappropriate pump, clogging, improper pipe fittings, and incompatible pipe diameters. This can be avoided by using a water pump with a capacity of 25 gallons per hour, conducting system maintenance, regularly inspecting pipes, and using appropriate tubes.

Have you already drawn in your mind how this would affect your hydroponic veggies and herbs? If you’re having trouble with this in your hydroponic system, I suggest keeping your eyes glued to this article.

1. Inappropriate Water Pump

A weak pump will not deliver and circulate water well in a hydroponic system. Whereas, a strong pump will overdeliver water which may lead to flooding. The recommended baseline water pump pressure is 25 gallons per hour (GPH) for a 2-hour cycle.

Recommended Water Pump Pressure
Recommended Water Pump Pressure

Here are water pumps that might fit your hydroponic systems. If you think a portion of this section is for you, take note of it!

Pumps for Small Hydroponic Systems

If you have a 2 by 3 feet nutrient film technique hydroponics or an indoor ebb and flow system, the product below on Amazon will suffice.

The maximum flow rate of this product is 50 gallons per hour (GPH), making it perfect for home-based hydroponics systems.

Pumps for Larger Hydroponic Systems

If you have an outdoor or commercial hydroponic system, a 300-GPH water pump would be a better choice.

This water pump could handle long hydroponic systems and can efficiently deliver nutrient water.

Pro Tip: More water pressure will be required for larger hydroponic systems. If you have a very long hydroponic system, you can choose water pumps with flow rates greater than 300 GPH.

2. Clogging

Clogging of pipes and hoses weakens hydroponic water pressure. This can be caused by biological impurities such as algae and plant debris or physical components such as growing medium, dirt, and suspended solids.

Pro Tip: These issues can be addressed by keeping the water at an optimal temperature, keeping light out of the water, cutting the roots, instituting strong roots before actually transplanting, and using filtered water.

   Learn more about this in our article on hydroponic clogging problems.  

3. Leaks from Improper Fittings

Pipe installation must be double-checked because leaks can cause water pressure to drop. This is undesirable because it wastes resources in the hydroponic system such as water and nutrients.

Check Pipe Installation to Avoid Hydroponic Water Leaking
Check Pipe Installation to Avoid Hydroponic Water Leaking

Aside from water pumps, another possible cause of low water pressure in hydroponics is improper pipe fitting.

This is especially true for hydroponic systems purchased online. I bought a nutrient film technique (NFT) hydroponics back then. It was thrilling for me because I was the one who put every pipe together.

Fun, right? Well, not entirely.

When I noticed my hydroponic water not reaching the top tube, I realized that it is critical for every hydroponic grower to thoroughly inspect pipe fittings during this step, or else your nutrient water may leak.

Pro Tip: Occasionally check your pipe fittings, especially for nutrient film technique hydroponics. Another prevention measure is using pipe glue or polytetrafluoroethylene (PTFE) tape.

4. Incompatible Pipe Diameter

In hydroponic systems such as the nutrient film technique, larger pipe diameters weaken water pressure while smaller pipe diameters strengthen it.

As you might have guessed, pipe diameter and water pressure have an inverse relationship. When we say inverse, as factor A increases, factor B decreases.

If you intend to build your nutrient film technique hydroponic system from scratch, this section is for you.

You must ensure that the diameter of your pipe is proportional to and appropriate for the size of net cups you intend to use.

The recommended pipe sizes for each net cup size are listed in the table below.

Net Cup Size (inches)Pipe Size Diameter (inches)
Recommended Pipe Diameter for Net Cup Sizes

Have you noticed a pattern in the table above?

You got that right!

Pro Tip: There must be a 1-inch allowance for water to flow and circulate throughout the system. At this level, the lower portion of the roots would be able to get enough water to supply your hydroponic plants with.

Aside from the diameter, one of the major concerns about pipes in hydroponics is their safety.

   Explore more on this concern in our article about PVC, is it safe for hydroponics?  

Other Hydroponic Systems

Hydroponic systems such as deep water culture, ebb and flow, and drip systems do not have this pipe diameter problem because these systems are operated with hoses. These hoses usually come with the system or with the air or water pumps, thus this is not that much of an issue.

2 Cons of Strong Hydroponic Water Pressure

Strong hydroponic water pressure will promptly raise the water level and result in overflowing. When water continuously fills the tubes to the top, it provides a favorable breeding ground for algae.

1. Raises Hydroponic Water Level Promptly

When there is strong water pressure, it takes less time for the hydroponic solution to get into the system.

Consider this scenario in the context of vertical nutrient film hydroponics.

High pressure will accelerate the flow of hydroponic water to the top pipe. When this occurs, the water has a high likelihood of overflowing because gravity must still pull the water downwards for recirculation.

What will be the result if this occurs?

2. Overflow Will Cause Algae Development in Net Pots

Because the pipes are filled in a shorter time, the plants will be submerged in water immediately. As a result, the overflow will moisten the top portion of the net pot.

Keep in mind that algae growth is aided by a combination of nutrient water access, sunlight, and hot solution. All of which are present in the scenario described above.

Since it is the top portion of the net pot, it is exposed to sunlight. Along with sunlight is a rise in water temperature. Finally, algae can grow with the nutrients from the overflowing hydroponic solution.

This is a problem that needs efficient disinfection.

   To know more about this, head to our article on hydrogen peroxide vs bleach.  

3 Cons of Weak Hydroponic Water Pressure

Inadequate hydroponic water pressure causes insufficient water level, root drying, and slimy water in the reservoir, which can serve as a breeding ground for pathogens and algae.

1. Insufficient Water Level

It will be difficult for the nutrient solution to transport toward the plant roots if the hydroponic water pressure is low.

Weak pressure will only fill a shallow portion of the tube in both horizontal and vertical nutrient film technique hydroponics. The same thing happens to the grow trays in ebb and flow systems.

What is the impact of this low water level?

2. Dries Out Roots

Water is required by roots to transport nutrients for growth. When water is not distributed evenly throughout the system, the roots dry out, the leaves curl from dehydration, and the plant eventually wilts.

Effect of Low Water Pressure in Hydroponic Plants
Effect of Low Water Pressure in Hydroponic Plants

3. Slimy Water

Weak pressure moves the water in the reservoir very little by little. This raises the risk of slimy water in the reservoir as a result of stagnancy. Slimy water can then serve as a breeding ground for pathogens and algae.

Water Maintenance Pro-Tips [Beginner Hydroponics]


Does strong water pressure increase hydroponic solution temperature?

Pressure and temperature have a direct relationship in general. This means that as pressure rises, so does the temperature. While this is true for other situations (e.g. boiling water), an increase in hydroponic water pressure has little effect on water temperature because of the absence of strong forces like direct flames.

Can strong water pressure wound the roots of my hydroponic plants?

The pressure capacity of hydroponic water pumps is insufficient to wound the roots of your hydroponic vegetables and herbs.

How do weak sprays affect aeroponic systems?

Weak aeroponic sprays will not properly deliver nutrient water to the roots. Aeroponically grown vegetables and herbs will dry out and develop weak roots. This causes leaf curling and yellowing, and ultimately death of the plant.

Summary of Hydroponic Water Pressure Problems

Hydroponic water pressure may become too weak or too strong due to use of inappropriate pumps, clogging, leaks from improper pipe fittings, and too big or small pipe diameters. Weak pressure may result in the drying of roots and eventual plant death. Strong pressure, on the other hand, can lead to algae bloom due to flooding.

It is critical to understand which pump is appropriate for a hydroponic system. A baseline flow rate of 25 gallons per hour is suitable for most home-based hydroponic systems. Clogging, on the other hand, can be avoided with proper water maintenance and sanitation.

Another hydroponic issue that can reduce water pressure is leaking, which can be avoided by inspecting pipe installation. Finally, it is critical to use pipe diameters that are an inch larger than the intended net pot size. This will provide enough space for the plants’ roots to absorb nutrient water.


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