What’s the Best Water for Houseplants? Tap vs Filtered vs Distilled vs Rainwater

The short answer is that we recommend filtered water as the best water for your houseplants. This type of water hits the sweet spot for nutrients the plant can use without the harmful additives and minerals in some kinds of tap water. You can make tap water work if you find water filters to be too expensive or cumbersome, and highly purified water can be useful for certain situations. For a safe and simple solution that works for every type of plant, filtered water is best.

Want to know more about the best water for houseplants? Here are all the details about the chemical composition and the effects each type of water has on your plants.

Using Tap Water for Houseplants

The effect of using tap water depends on the type of plant and the exact composition of the water, but what water you use can certainly influence the health of your houseplants. In most locations, tap water has fluoride added to it. It’s important that plants have some of this naturally occurring element, but too much can be harmful. Fluoride levels in tap water are rarely fatal to houseplants on their own, but they can affect almost every aspect of the plant’s growth process including photosynthesis, respiration, protein synthesis, carbohydrate metabolism, and nucleotide synthesis. The most common sign of too much fluoride is usually yellow or brown leaves, which can be a symptom of many things. Likewise, if the rest of your houseplant care is spot on, the plant may be able to cope with excess fluoride for many years. However, the plant will inevitably be more vulnerable to overwatering, underwatering, pests, and other common houseplant ailments.

The other reason to hesitate before watering houseplants with tap water is the salt content. Hard water is chock full of calcium deposits, which can dry out plant roots and prevent them from absorbing water.  The most common solution for “hard” tap water is to add a water softener. Unfortunately, this additive can lead to high levels of sodium, which can also interfere with water absorption. Another way to combat the problem of hard tap water is to occasionally add tiny amounts of vinegar to water you give to houseplants. When taking this route, we recommend monitoring the soil’s pH level to make you’re striking the right balance. There may also be detectable levels of forever chemicals from pharmaceuticals and other household products with unknown effects on various types of plants.

Using Filtered Water for Houseplants

The best solution that should work for pretty much every houseplant is filtered water. This type of lightly purified water is great for removing most common toxins and large particulates in tap water, while leaving enough minerals and nutrients that the plant can use to catalyze growth. This includes inline water filters, pitchers with built-in filters, and other basic water filtration systems. You do not need to pay extra for distilled water for houseplants. Not every water additive hurts houseplants. Chlorinated water, for example, is safe for most houseplants.

This type of filtered water for houseplants is relatively expensive. It’s also create a great source of drinking water for the entire household. Whether you don’t trust your local tap water or just don’t like the heavy mineral taste, using filtered water can ensure your family and your houseplants are healthy and happy.

Using Distilled Water for Houseplants

Distilled, reverse osmosis, and other highly purified water may have the opposite problem as tap water. Too many of the minerals and nutrients found in most types of water are removed. Here, too, it’s not that using purified water will necessarily kill or even harm your houseplants. Rather, it means that the plant will have to get all the nutrients it needs from the soil. With this in mind, using distilled water with hydroponic plants isn’t going to work. We don’t recommend using highly purified water in most cases, but we won’t completely rule it out. We could see experimenting with distilled water if, for example, you’re trying to grow an unusual houseplant from a different part of the world and trying to tightly control the amounts and access of various nutrients to the plant.

Using Rainwater for Houseplants

If you’re up for collecting rainwater, this is another great choice that’s just as good or even better than filtered water. While rain does contain dust, pollen, and other atmospheric particulates, it does not contain heavy minerals or other chemicals frequently found in tap water. Moreover, most rain is mildly acidic which is great for houseplants, which generally prefer a slightly-acidic-to-neutral pH level of 6.0-7.0. Unless you live in an area known for poor rainwater quality or you’re unable to safely collect and store the water, then you shouldn’t have any reservations about using rainwater for houseplants.

Best Watering Practices for Houseplants

More than just knowing the best water for houseplants, you need to know how often and how much to water your houseplants. Learn the basics for watering houseplants as part of our houseplant care guide.