The Best Shower Water Filters, According to Experts

If you filter your drinking water to avoid potentially harmful chemicals, it’s not a huge leap to consider a shower water filter. According to Olga Naidenko, Ph.D., a senior science adviser at the Environmental Working Group (EWG), chlorine, a by-product of water disinfection, is commonly found in municipal water supplies, as are hazardous volatile organic compounds (VOCs), including the carcinogenic trichloroethylene. These chemicals don’t have to be ingested to cause health problems, she says, as studies have shown that lifeguards and frequent swimmers at indoor pools with high levels of chlorine have experienced problems such as exacerbated asthma symptoms.

There are also aesthetic reasons for filtering your shower water: “Many people notice that their hair is drier when they shampoo with hard water, that it frizzes more easily, and that not as much lather is created,” says Anabel Kingsley, a trichologist (hair and scalp specialist) at the Philip Kingsley Clinic. Hard water contains minerals like calcium and magnesium that can dry out the hair and skin. Water softeners and filters can remove these elements to relieve issues like dry skin or dandruff. Luke George, founder of the site Mr. Water Geek, says shower-filter users find that they have “softer hair and skin, hair color that lasts longer and is better able to maintain its gloss and shine.”

When selecting a filter, Naidenko recommends first searching your zip code in the EWG’s tap-water database to see what substances have been found in your area’s water supply, then looking for filters that are certified to remove or reduce those specific contaminants. According to our experts, there are generally two design styles of filters: all-in-one models with a filter built in to a showerhead, and “inline filters” that are made to be installed between your shower arm — the pipe that delivers the water — and the showerhead. Inline models generally have universal adapters, so you should be able to easily attach everything (don’t forget the plumber’s tape). Below, we’ve rounded up the filters recommended by our nine experts, and we’ve also noted which have been certified by third-party testing for targeting common contaminants. Although most are inline filters, there are some all-in-one options as well, depending on your preference.

In oxidation reduction (or redox) filters like this, a copper-zinc alloy, exchange electrons with contaminants, including metals like lead and mercury, to chemically convert them to harmless substances. The most commonly used type of redox material is the proprietary kinetic degradation fluxion (or KDF) formulation. According to Alexander Venet, the founder of custom-water-filtration company Molecule Project, KDF is the way to go.

While carbon filters “absorb” chlorine and other contaminants, KDF works differently. As Venet explains: “It has granular copper and zinc, which work to make an ionic exchange to the chlorine and changes it into a chloride, which is not harmful.” He adds that it also helps eliminate bacteria, because “once bacteria touches the copper and zinc, it gets killed off.” Venet says Sprite filters are some of the best around. “They do it right. They use KDF-55. Copper is expensive, so if you use KDF-55, you’re not cutting corners.” This filter is certified by the National Sanitation Foundation, which, according to Stefan Buck, business unit manager for filtration at NSF International, means the filter has met the public health and safety organization’s requirements “for chlorine reduction, material safety, and structural integrity.”

While this “high output” filter also comes with a showerhead, we’re including it with the inline models because you can easily swap in your existing head if you prefer. If you’re not into the white look, Sprite also makes a chrome version (without the extra head).