What is the Best Water to Use for Hydroponics?


Before you say that you’re confident of your water supply for your greeneries, think again. The standard of tap water is doubtful in many places and it can be harmful to your plants.

With that, this article will introduce distilled water and its effects on plant growth. 

Introducing, Distilled Water

Distilled water is obtained through the process of distillation. By utilizing the fact that everything in nature has a specific boiling point, this process allows the separation of substances to yield chemicals like alcohol and distilled water.

Water found in nature is never pure so the help of steam distillation is enlisted to eliminate most of the impurities and substances such as dissolved gases, bacteria, and organic chemicals.

Voila! You got yourself some distilled water. 

Watering Plants With Distilled Water: Against 

Before kicking off this discussion, we need to establish an understanding that distilled water is not always better for your plants than pre-distilled water. 

Although water found in nature has harmful substances due to pollution, it does have soluble minerals that are great supplements for your plants’ growth. That’s why we have turned to processes like distillation to rid our water of these contaminants.

If your plants are grown outdoors, you won’t necessarily need distilled water unless your water supply is seriously contaminated. Thankfully, the plants themselves normally have systems that fight against pollutants. 

In fact, the soil also prevents pollutants from reaching the plant roots. That said, an accumulation of impurities can occur, hindering plant growth. Nature’s answer to this is rain, which flushes these impurities out of the soil. 

Basically, watering your plants with tap water should be fine if they are planted outdoors. 

Watering Plants With Distilled Water: For

On the other hand, if you are a proud owner of hydroponics or any indoor planting bed, distilled water is suitable. Given the relatively enclosed grow beds in these setups, rain cannot act as drainage, making it easy for pollutants to accumulate. 

Since the build-up of these impurities can prevent your plants from thriving, many greenhouse owners opt for distilled water instead, especially when their plants are young or delicate. 

The effects of water on your plants are multiplied when it comes to hydroponics, which eliminates the use of soil altogether. As you can expect, the lack of soil increases the odds of impurities building up. 

Additionally, the water contents and pH levels greatly affect the outcome of your plants as well. Unless you want malnutritioned plants that are plagued with impurities at its roots, sub-standard tap and well water should be avoided. To be safe, go for distilled water.

Hydroponics boasts its highly manual system that gives owners a sense of autonomy. Distilled water and its contents are just additional aspects that hydroponics owners can control. 

Level of pH & Mineral Matters

If you have done your research, you’ll know that in hydroponics, the pH level of your water plays a major role in the absorption of nutrients for your plants. Thus, I can’t stress enough the importance of regularly monitoring the pH levels.

In some cases, the yield of hydroponics is less than satisfactory when growers use distilled water. Rather, when they switch to tap water, they obtain better crops. This can be attributed to either the pH level or the level of minerals, i.e. hardness. 

You should aim for a pH level of about 6.1 (give or take 0.3) for your hydroponics to allow maximum absorption of nutrients. Distilled water has an initial pH of 7 which will lower to about 6 after exposure to carbon dioxide. So if you are using distilled water, ensure that the pH stays between 5.8 and 6.4.

Water hardness refers to the level of soluble minerals in the water (e.g. magnesium and calcium). Natural water does have a noticeable hardness and the minerals do make the solution more alkaline which is crucial for crop development. 

Nutrient blends for hydroponics work best with water of low or middle hardness levels. Since distilling tap water will entirely remove all minerals, adding nutrient blends will throw the pH balance off. To solve this, simply add Cal-Mag supplements to the distilled water. 

To summarize, for distilled water users, monitor the water pH, add Cal-Mag moderately, and check pH once again to ensure that it is in the optimal range.

DIY Distilled Water

On top of purchasing distilled water from a nearby shop, which can be a pricey option, you can also make a one-time investment in a water cooler that lets you make many batches of distilled water thereafter. 

These are surely an option for most plant growers out there. Alternatively, one can simply make distilled water right in the comfort of their home. 

There are plenty of online resources such as a video tutorial that can guide you in distilling your water every step of the way. But here is the foundational idea behind distilling water.

Firstly, you’d want to set up a closed container filled partially with tap water. Within this container, fit in a bowl or other catchment devices of your choice either by hanging it or afloat the water. Then, close the container with a cold lid that is pre-cooled with ice or cold water. Boil the water in the container. The water will then evaporate up as vapor and condense on the cold lid to be collected by your strategically placed bowl. 

The water in the bowl will be pure distilled water. If you want, you can even use apparatus from a chemistry lab for a more intricate distillation process. 


Purifying water with tedious methods like distillation can require significantly more energy and money than simply using normal tap water. So, if you’re growing plants out of interest, then tap water should suffice. A heuristic you can use is any water that you can consume safely is plant-safe as well. Just make sure to get rid of pollutants like chlorine and you’re good to go.

Consider using distilled water only if your water supply is seriously contaminated or your plants are incredibly delicate. 


Share on facebook
Share on twitter
Share on pinterest
Share on linkedin