Is Tap Water Ruining Your Skin? A Dermatologist Tells All

You've probably used a filter to mask imperfections in a photo—more than 90 percent of young women do so regularly, according to a 2021 study—but should you actually be using filtered water to improve your skin?

In most homes, the water you use to wash your face is the same as what comes out of the kitchen faucet, the water many of us drink every day.

As the Centers for Disease Control and Prevention explains, the U.S. "has one of the safest and most reliable drinking water systems in the world." There have been cases of water supply contamination, most notoriously in Flint, Michigan, but these are rare.

So, what does ordinary tap water do to your skin? It's a hot topic on #skincare TikTok. Videos suggesting that hard water is connected to eczema, acne and psoriasis have hundreds of thousands of views. Some of the companies that make filters for faucets and showerheads are going viral too, with more than 1 million searches.

Newsweek asked Dr Gloria Lin, a board-certified dermatologist with the Schweiger Dermatology Group in New York, how the water we use can affect our skin and whether filters are the answer.

What's in Our Water?

Normal tap water contains metals such as zinc, copper, iron, calcium and magnesium—all substances we need in certain amounts to keep the body healthy from the inside out. Hard water has higher concentrations of minerals, particularly calcium and magnesium.

The South-west has some of the hardest water in the U.S. Extremely high levels of calcium and magnesium are found in New Mexico, Utah and the Western part of Texas, as well as in Wisconsin, Indiana and Florida. Softer water states include Washington, Oregon, Arkansas, New York and Alabama.

Lin told Newsweek that hard water "can disrupt the skin barrier and cause dryness by depleting the skin of its natural oils."

The minerals "can also bind to surfactants found in soaps and cleansers that make it harder to remove from the skin, leaving a residue behind and resulting in clogged pores."

Mineral ions in harder water can cause free radical damage too, leading to collagen breakdown and ageing the skin.

"Hard water also has higher alkalinity compared to normal skin, which is slightly acidic, causing a pH shift that can disturb the skin's natural function," Lin said.

How Might Tap Water Affect Our Skin?

A buzzword in the beauty industry in recent years is the skin microbiome, the layer of living organisms on your face and body that needs to be kept in balance. "Maintaining a healthy skin microbiome is an important emerging field of research," said Lin.

Tap water can play a role here too. "Unfiltered water may disturb the natural balance of skin flora, exacerbating conditions such as acne, eczema and dermatitis."

Unfiltered water might also contain chlorine, chemical contaminants, hormones, bacteria and fungi—and this could be a concern, according to Lin.

"Given the extensive body surface area that the unfiltered water is in contact with, there has been debate regarding possible absorption of these pollutants systemically, through the face or body," she said.

Hair can be negatively affected by unfiltered water too, "causing it to lose its natural shine and become dry and brittle."

Can a Tap Filter Help?

Depending on your location, quality of tap water and skin type, it may be beneficial to drink and wash with filtered water, according to Lin.

"As the heavy mineral content can exacerbate dryness and impair the skin barrier, this can significantly affect those with more sensitive skin in conditions like eczema," she said.

"The minerals that can bind to surfactants in cleansers and soaps, leading to residue on the skin or soap scum in the shower, can cause blocked pores, which may negatively affect those with acne-prone skin."

She added: "Those who are concerned about potential aging due to free radicals can also consider filtration because the effects for this would be more long term and not necessarily seen on a day-to-day basis."

Lin also pointed to studies on the connections between hard water and eczema by Dr Zarif Jabbar-Lopez, a dermatologist based in London. Jabbar-Lopez and colleagues are investigating the use of water softeners to help prevent eczema in newborns. The condition affects up to 25 percent of babies in the U.S., according to the American Academy of Dermatology.

If you're not sure whether this applies to you or your family, Lin has this advice: "If you haven't experienced any significant side effects with the unfiltered water, then it may not be necessary to filter it.

"However, if you have experienced negative effects after bathing, or notice that your skin markedly improves when traveling, then consider filtration."

How Much Are Water Filters?

Faucet filters start at around $20 and showerheads at about $150, but you need to factor in the cost of replacement cartridges too. Filters can become a breeding ground for bacteria, undoing all their good work for your skin. One manufacturer, Filter Baby, suggests changing its filter every three months or two months in particularly hard water areas.

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