Where Water Comes From: Sourcing Water for Your Hydroponic Garden

By Susan Eitel
Published: November 21, 2019 | Last updated: April 30, 2021 12:38:00
Key Takeaways

There are many places where water comes from, and each source affects your plants differently. Read on to learn about the different water sources you are likely to encounter as you enter the realm of hydroponic growing.

Source: Michael Melgar/

The wonderful thing about the Internet is that there is so much information available at your fingertips. But the same can also be said about the frustrating parts of the internet as there is more information available than we can possibly filter through. It is like drinking from the virtual fire hose and you are being deluged by well-meaning advocates from all the different camps: tap water, well, rain, reverse osmosis, distilled and others.


For the novice gardener, this can be both intimidating and paralyzing, but it is not necessary to have all the answers upfront to be a successful grower. It may take time to refine your techniques.

Don't forget that you are also building a new vocabulary and knowledge base. Here are a few simple rules to help point you in the right direction and make your experiences as stress-free as possible. In a nutshell, here is a look at some of the different water sources you will encounter as a hydroponic gardener, and what each one could mean for your plants.


Tap Water

Tap water is unique to every municipality and will probably test differently depending on where you live. The greatest concern is the level of chlorine that is put into the water supply. Plants do not like chlorine and the second concern is that it eliminates all the beneficial bacteria.

Although chlorine dissipates in water after a day or two, newer chlorine-based chemical additives may not. The bottom line is that you will be able to get good, but maybe not ideal, results from using tap water. The one exception to this is treating water with water softeners. Keep in mind that high salt content can kill the plants.

Read More: Tap Water and Its Impacts on Hydroponic Nutrients and Supplements


Well Water

This can potentially be one of the least desirable of all the options. Some wells, but certainly not all, can have extremely high mineral content. Although not an insurmountable problem, it takes greater skill and knowledge on the part of the grower. It could certainly create a challenge for a novice gardener. You should have your water tested and take the results to your local hydroponic retailer for recommendations. They will be able to help the beginner make sound choices for optimal results.


This one can also fall into the questionable bracket as pollutants are often the particulate matter that raindrops form around. Many people have great success with rainwater but living downwind of a chemical plant may make you think twice. Follow the same advice that you would for well water.


Read More: Harvesting the Rain - How to Properly Collect Rainwater for Reuse in the Garden

Distilled Water

Distilled water has many of its impurities removed through a process called distillation, which involves boiling the water and condensing the steam into a new container. Because of this treatment process, distilled water is more costly and can have a lower pH value than what is desirable. However, distilled water is prized for its lower mineral content. You can easily enjoy a good crop using it; just keep an eye on the pH levels.

Reverse Osmosis

Reverse osmosis (frequently referred to as RO) is the preferred water source for most growers. Be aware that it comes with a price tag, but many home systems are quickly becoming more affordable, making it worth a very serious look. RO produces a consistent water supply and has fewer worries than other sources due to its low mineral content and preferred pH level.

Read More: How to Get the Most Out of Your RO System

UV System

The wavelength of ultraviolet (UV) rays is lethal to bacteria. In a UV system, as the water passes by the UV bulb, any living microbes are immediately destroyed. Separate filters can be installed to trap sediments. The combined result is a potable water supply. A UV system can be installed at the water source as it enters the building, purifying all water on-site, or smaller units can be installed directly to a single faucet purifying the water at only that selected location.

UV bulbs must be replaced annually, but the cost of running the system is no more than the cost of powering a low-wattage light bulb. Plants need beneficial bacteria and these can be added quite easily after the water passes through the UV system. Like RO systems, they come with a larger price tag, but they are becoming much more affordable, especially the smaller site-specific models.

Read More: Tanning Your Plants - The Curious Effects of UVA and UVB

The information above is only a cursory examination of water systems available to the hydroponic grower, and admittedly, it is neither complete nor robust. The fervor created over preferred systems can be quite intimidating to the beginner, but hopefully, this article will help dispel the anxiety of information overload and instructional bias.

Learn, have fun and most importantly, don’t be afraid. No matter the source, plants tend to grow better with water than without.


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Written by Susan Eitel

Profile Picture of Susan Eitel
Susan Eitel has a degree in landscape horticulture from Humber College in Toronto, Ontario. She has worked in the hydroponics industry for more than 25 years. Susan has always been interested in beneficial insects and integrated pest management. She lives in the Niagara area with her beloved husband and dog.

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