Which Water Is Best for Plants - Distilled or Filtered?

There are many types of water out there, so it’s important to know the difference between them so you can make an informed decision about the best type of water to use on your plants. Among the options, the most popular and commonly discussed are distilled and filtered water for plants. To help you decide, we’ve provided a breakdown of each.

Distilled water is a type of purified water that has gone through a rigorous process that includes boiling water then condensing the vapor. While the distillation process helps remove contaminants that can be harmful to plants, it also removes minerals that are good for plants.

Over time, using distilled water for plants can result in stunted growth and discoloration because they aren’t getting the nutrients they need. To compensate for the lack of nutrients in distilled water, some people suggest adding powdered or liquid nutrient supplements to the soil or water you use for plants. Overall, distilled water can be good for plants because it helps remove contaminants, but the lack of nutrients means you may need to use a supplement or consider another type of water.

Filtered water, on the other hand, is tap water that has been treated by going through a filtration process that removes contaminants such as chlorine, chloramine, lead, and other bacteria. There are several types of water filters that use different processes, technology, and media, including activated carbon, ion exchange, mechanical, ultraviolet, and reverse osmosis.

Not all water filters do the same thing. For example, ultraviolet filters are great at removing viruses but won’t help with removing contaminants like fluoride that can harm plants. As such, it’s important to do research before buying a water filter to make sure it actually removes contaminants present in your water that are harmful to plants. When doing so, look beyond product reviews and check that the filter you’re looking at has been certified by an independent testing agency like NSF or IAPMO.

In general, you’ll want to consider activated carbon, ion exchange, or reverse osmosis filters to provide the best water for your plants. Out of these options, reverse osmosis is the most effective method for removing the largest number of contaminants. However, much like distilled water, the reverse osmosis process can sometimes remove healthy nutrients which is why you should look for an RO system that contains remineralization technology like the Aquasana OptimH2O® Reverse Osmosis + Claryum® Filter. This system uses four methods of filtration to remove 5x more contaminants than other RO systems, and utilizes remineralization technology to add healthy minerals after the reverse osmosis process. Furthermore, this filter is also tested and certified to NSF/ANSI Standards 42, 53 (includes P473), 58, and 401, for the removal of 95% of fluoride and mercury, 97% of chlorine and arsenic, 99% of lead and asbestos for a total of 88 contaminants reduced.

As an alternative to reverse osmosis, activated carbon filters are also great for plants. Activated carbon water filters use a material like wood or coconut shell that is heated to produce a charred substance. The char is then treated to make it highly porous, so when water passes through it contaminants stick to the material through a process known as adsorption. We offer several types of activated carbon filters including under sink, countertop, and whole house systems that are all great for providing healthy water for plants. If you have plants throughout the house, we recommend a whole house system because it enables you to have filtered water out of every tap in your home.

In a nutshell, the difference between distilled water and filtered water is that distillation strips away all the natural minerals found in water as well as chemicals like fluoride and chlorine. The best water filtration systems remove harmful contaminants while retaining the natural minerals you and your plants need. So make sure to choose a water filter that is certified to remove contaminants but won’t strip away beneficial minerals in the process.

Some plants are more susceptible to contaminants found in tap water. Foliage plants, in particular, are most often affected so if your plant shows signs of fluoride or chlorine toxicity, switch to filtered water instead. One way to find out what’s in your tap water is to do a quick online search to see if there are any harmful chemicals your plants are sensitive to, and cross-reference that with a list of the chemicals found in your city’s tap water. One way to do this is by entering your zip code in EWG’s Tap Water Database who’s been documenting water quality since 2012 and has over 32 million state water records. Knowing what’s in your water can help you determine what kind of water filter you need based on the contaminants you’re looking to remove.