5 Houseplants That Are Surprisingly Sensitive to Hard Water

A potted green plant with elongated leaves and a single white bloom placed on a wooden table in front of a window — Credit:
Grumpy Cow Studios / Getty Images

If you've noticed white spots on your houseplants or brown, wilting leaves, it's possible hard water is to blame. Hard water contains high mineral content, such as calcium, magnesium, and iron, that can harm houseplants over time. While many plants are resilient enough to withstand hard water, others are surprisingly sensitive to it and will let you know something in its environment is amiss. Before treating for pests and diseases or moving your plant to a brighter location, consult this list of the houseplants that don't tolerate hard water.

Robin Trott, horticulture educator with the University of Minnesota Extension
Lee Miller, author of The Houseplant Guide: How to Easily Select & Maintain Indoor Plants, with over 40 years of experience with indoor plants

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Spider Plant

Known for their fast-growing, sprawling growth habit, spider plants are among the most common houseplants to show damage from hard water. "Brown leaf tips, often blamed on low humidity, are more commonly caused by a buildup of fluoride and dissolved salts found in many municipal water supplies," says horticulture educator Robin Trott. "These minerals are readily absorbed and tend to accumulate at the leaf tips over time." Hard water can also keep the roots from absorbing water properly.

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Peace Lily

Peace lilies produce lovely white 'flowers,' which are actually modified leaves called spathes. These white leaves provide a beautiful backdrop for the rod-like spadix, which contains the true peace lily blossoms. "Peace lilies also respond quickly to poor water quality," says Trott. "When watered with hard, mineral‑rich water, they may develop brown leaf edges, yellowing foliage, and fewer blooms, even when light and watering practices are otherwise appropriate." He adds that fluoride in the water is typically the primary cause of these issues.

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Orchid

Delicate and beautiful, orchids might seem as though they'd be tricky to grow, but they can be surprisingly easy to keep as houseplants. One thing they can be picky about, however, is water. Exposure to hard water can cause various issues, such as leaving unsightly mineral deposits on leaves. Watering with rain or distilled water is ideal for these plants.

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Calathea

The lovely calathea is grown primarily for its vivid leaf pattern, which adds visual interest around the home. To maintain its vibrant foliage, avoid watering calathea with hard water. "Heavy metals, chlorine, and fluoride build up in the soil, resulting in stunted growth, browning to the outer edges of the leaves, and possible further damage," says houseplant expert Lee Miller.

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Prayer Plant

Another houseplant with a stunning striped leaf pattern, prayer plants require a bit of horticultural know-how, and they also need proper water for best results. "Prayer plants are valued for their patterned foliage, but are particularly sensitive to mineral accumulation around the roots," says Trott. "Because they prefer consistently moist soil, salts from hard water build up more quickly, leading to leaf tip burn, spotting, or faded leaf color."

How to Improve Hard Water

If you suspect hard water is causing issues for sensitive houseplants, don't worry. There are alternatives you can use instead of tap water. "Whenever possible, rainwater is the best choice; it is naturally soft and free of added chemicals," says Trott. Rainwater can easily be collected on a porch or deck and brought inside. Another suitable option is distilled water, which can be purchased or made at home.

However, if tap water is the only option, Miller recommends letting it sit out for 24 hours to help reduce its chlorine content. But note that this method will not remove fluoride or dissolved salts.

5 Houseplants That Are Surprisingly Sensitive to Hard Water, According to Plant Experts