Our Guide to Using Tap Water for Hydroponics

Hydroponics have taken the plant cultivation world by storm over the last few years. This innovative way of caring for plants without soil has fascinated nature enthusiasts by way of the lush greenery hydroponics often produces. It often surprises them that these thriving plants grew from having their roots submerged in nutrient-rich water.

If you’re new to hydroponics, you may be wondering if tap water is safe to use with your plants. Hydroponics requires precision, so it’s important to be fully aware of the kind of water you use to nourish your plants. Although you can use tap water with your plants, you’ll have to take additional steps to protect your plants from tap water’s chemicals. 

The Contents of Tap Water

Most areas have potable tap water, but that doesn’t mean it’s safe to use on plants in a hydroponic system. As these plants take their nutrients from a hydroponic grow solution provided by the grower, it’s essential to ensure uninterrupted access to these nutrients. 

Tap water is specially treated to remove harmful organisms and make it safe for human consumption. However, it needs to be further purified for hydroponic use. That’s because additional substances are added to clean the water, such as chlorine or chloramines, which kill waterborne bacteria. The treatment also adds aluminium sulfate, which makes the impurities stick together for easy removal. 

Although plants need the nutrients in chlorine, they require it only in small quantities. As this is already present in tap water, the grower no longer needs to add it to the nutrient mix. However, your hydroponic plant enhancer already contains these metals, which means that the plants will absorb too much of it, resulting in stunted growth. 

The Steps to Prepare Tap Water for Your Hydroponic System

There are a few ways to remove the metals from your tap water to make it suitable for your hydroponic system. However, you’ll have to know beforehand what exactly you’re hoping to purify from the water. Although removing chlorine is a fairly simple process, it can often be time-consuming. 

To remove the chlorine, simply let your water sit in strong, direct sunlight for 24 hours. In this period, the UV rays will allow the chlorine to dissipate from the water. If you have large volumes of water, this step may take a while to accomplish.

To remove chloramine, you can opt for chloramine-removing tablets like Campden. Add one tablet for every 20 gallons of water you use. The tablets remove both chloramines and chlorine, making them an easy solution to make your tap water safe for your hydroponic system. You can also run your water through an activated carbon filter.

If you are treating hard water, you’ll have to clean it from its calcium and magnesium contents. It’s best to use reverse osmosis filters, which you can install in your home plumbing system. These kinds of filters offer numerous benefits to your health as they thoroughly purify water, making them a worthy investment. 

However, if you’re selecting one specifically for your hydroponic needs, you’ll find one that comes with carbon and sediment filters. Although these can be expensive, they prevent your plants from dying thanks to contaminated water, saving you money in the long-run. However, they produce wastewater while generating clean water.

Other Ways to Find Safe Water for Your Hydroponic System

Apart from tap water, you can also use rainwater for your plants. Harvesting rainwater is one of the most cost-effective ways to plant your indoor garden, but they will require the construction of a water collection system. 

You can also use distilled water, which is convenient to use thanks to its wide availability. It’s sterile water, so you don’t have to clean it of any contaminants. With that said, it lacks calcium and magnesium, so you’ll have to ensure your nutrient solution contains these minerals.

Deionised water is another good option for your plants. This kind of water started as regular water but was electrically charged and processed to eliminate all excess salts. The result is incredibly pure water that is similar to distilled water.


Tap water is an accessible solution to use for your hydroponic system, but it cannot be used as-is. Fortunately, tap water is easy to treat, making it a valuable resource for supporting your plants. By following the steps above, you’ll have a steady stream of water supply to nourish your hydroponic system. 

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