By Steven Voser

With the complexity of modern growing techniques, the quality of your water is a factor that is easy to overlook. Yet, water is a crucial building block of life, for both plants and humans.

In cannabis plants, clean water is responsible for transporting nutrients, triggering transpiration, and making photosynthesis work. However, choosing the right water source for your plants can be tricky, especially if you are growing on a budget.


High-quality water is a crucial ingredient in producing high-quality cannabis. Relying on low-quality water could seriously hamper your plant’s health and its ability to produce excellent buds.

Aside from water quality itself, growers must also consider their budget and willingness to spend on this resource. Apart from the upfront costs of setting up and establishing certain kinds of water sources, there are also the long-term costs of keeping the water flowing. Moreover, certain water sources may be more time-consuming and burdensome to operate than others.

The water source you choose will undoubtedly affect the quality of the water being fed to your cannabis plants. While there are numerous ways to obtain water for your plants, some are much more costly or time-consuming than others.

Beginning with the most expensive, here are 4 water sources you should consider using for your cannabis grow.


If money is no concern, then water filtration systems are the way to go. There are numerous filtration systems available, however, cannabis growers usually opt for an RO (reverse osmosis) system. These systems work by forcing water molecules through a semipermeable membrane and filtering out contaminants in the process.

The primary advantage of a water filtration system is having an unlimited supply of clean water on hand. Furthermore, RO systems are generally considered to be the safest and purest choice for large-scale water filtration. Despite this, the initial startup cost of establishing such a system tends to scare most growers away. Even the most basic RO system can cost several hundreds of dollars to purchase.


Rainwater is widely considered to be clean and pure, making it especially great for hydroponics. However, thanks to modern pollution, rainwater may not actually be as clean as most people would like to think. Moreover, collecting and using it can be quite a hassle.

Rainwater is typically collected using a water collection system. Raincatchers vary in build, size, and shape. While some may be more costly and difficult to assemble and operate, others can be built at home using commonly available materials. Furthermore, most of these systems can be maintained with very little time and effort.

Some water filtration systems can even be modified to collect recycled and uncontaminated “gray water” from other local sources. However, some jurisdictions have decided to either prohibit or limit the collection of rain or gray water. As such, it is best to make sure that collecting rainwater is actually legal in your jurisdiction before investing in a collection system.

The key to safely growing with rainwater is, like tap water, testing it before use. Adjustments to pH levels and mineral content may be necessary.



Distilled water is a great source of pure and uncontaminated water. Especially for small grows. Unlike tap water, you can rest assured that distilled water will not require any extra filtering. Bottles of distilled water can typically be purchased from local grocery stores, or can even be delivered to your home in some areas.

However, while one bottle may seem relatively inexpensive, the cost certainly does add up over time. Additionally, some growers argue that filtered tap water can be just as pure. Therefore, distilled water may not be ideal for large gardens or for growers on a tight budget.


Unfiltered tap water is one of the most readily available water sources for marijuana growers. It is relatively inexpensive and very easy to get. And, despite popular opinion, it’s not actually all that bad for your plants.

However, the quality of tap water differs in each municipality. You may find that tap water in some areas contains more contaminants than in others. Chlorine, magnesium, and calcium are all commonly found in tap water, to varying degrees. Too much of these won’t kill your plants, but they can seriously affect its biological activity.

You should always test your tap water before use. Not only will you find out exactly what is inside of it, but you may be able to devise a filtration strategy. For instance, chlorine tends to evaporate naturally if left to sit in water for 24 hours. Meanwhile, chloramines can be filtered out with an activated charcoal filter, and fluoride can be filtered out using an activated alumina filter.


Part. 1: pH Good quality water is a foundation of a great cannabis grow.

Part. 2: PPM & EC Here is part two of our guide, focusing on PPM and the EC of your water.

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