Dry skin and crunchy hair are just some of the side effects.

By Hana Hong
September 17, 2020
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For the longest time, I thought water was just, well, water. Sure, I can taste the difference between a bottle of Fiji versus a glass of tap, but I also assumed that any unpurified water that came from a faucet was the same. That is, until I met with a dermatologist one day who presented me with a list of alarming statistics.

In case you’re not aware, hard water is the term used to describe water high in dissolved minerals, largely calcium and magnesium. On the flipside, soft water tends to have higher concentrations of sodium. Some states have higher concentrations of hardness in their water (like New Mexico, Utah, Indiana, and Florida), whereas other states have less.

So why does this matter? Since hard water contains essential minerals, it is sometimes the preferred drinking (and cooking) water. However, this takes quite the toll on skin and hair. “Calcium and magnesium in hard water react with fatty acids in your soap and shampoo to form chemicals that coagulate,” says Tess Mauricio, a board-certified dermatologist in Beverly Hills. “As a result, your skin doesn’t get cleaned properly and the chemicals leave a residue on your skin.”

Over time, this skin residue can disrupt the skin barrier. “It causes your pores to clog up, which, in turn, can lead to acne and exacerbate skin conditions like eczema and dermatitis.” And that’s not all: Hard water can affect the skin on your scalp, too, causing dryness and that telltale itch. “You may notice your hair lose its color and not look as shiny with long-term use,” says Mauricio. 

Although it’s impossible to tell the difference at first glance (I definitely couldn’t taste it), people with hard water might notice that soap and shampoo don't lather as well. Your skin might also feel like there is a layer of residue and doesn’t feel as “clean” even after rinsing. 

So here’s the million dollar question: How bad is it really? Well, it’s a judgment call. Most people can’t even tell if they have hard water. If you haven’t experienced any significant side effects in your unpurified water (read: dryness and skin irritation), you should be fine with going unfiltered. However, if you find that you’re experiencing negative effects (especially right after washing or showering), you might want to tweak your water exposure. 

This is especially true for those with sensitive skin, psoriasis, or eczema, whose skin barrier isn’t strong enough to withstand all the hard minerals. “Chronic use of hard water for cleansing can irritate the skin and make these conditions worse,” says Mauricio. “For those with really sensitive skin, even laundering clothes in hard water can cause skin irritation.”

This can also be an explanation for why your skin changes (for the better or worse) when you travel. Because different locations have different levels of hardness, even a standard shower can reap drastically different effects. “When you are used to hard water and travel to a place with a water softener, the changes on your skin and hair will be noticeable immediately. Your skin will feel smoother and cleaner,” says Mauricio. 

If you’ve noticed that your skin improves dramatically when you travel elsewhere, there’s a high chance that your water is to blame. For these people (and ones who experience sensitivity right after they shower), getting a good mineral filter for your faucet and showerhead is the best move. 

There are also additional steps you can implement during and post shower to counteract the effects of hard water. Try cleansing with micellar water, like Vichy Purete Thermal Mineral Micellar Water For Sensitive Skin ($15; walgreens.com), which removes tiny particles and doesn’t require rinsing with water. As for your hair, clarifying shampoos or similar astringents like apple cider vinegar contain chelating agents that bond to the excess minerals on the hair, allowing them to be removed.

“Do not use hot water, which further dries the skin,” adds Sejal Shah, MD, a board-certified dermatologist in New York City. “After washing, gently pat dry the skin and while it is still slightly damp and immediately apply a moisturizer with ingredients that hydrate and help strengthen the skin barrier, such as ceramides and niacinamide. This will help give you the best skin results.”