Out of all the skin-care products you could have in your regimen, some people say that the toner is the most superfluous. It’s even kind of controversial, as plenty of people argue that it’s a totally unnecessary beauty product to buy, while others wouldn’t dare apply serums without toning their skin first. Whatever camp you’re in, though, one thing rings true: You should use a toner if you’re working with hard water.

A refresher—hard water is water that’s chock-full of magnesium and calcium that can complicate your complexion game by acting like free radicals. That’s compared to soft water, which has only minor levels of these. Signs you have hard water include having mineral deposit streaks on your dishes after washing them or buildup on your faucets or shower head. While you can definitely invest in a water softener that attaches to your faucets, an even easier solution is to—yep—swipe on a facial toner.

“Toners are liquid skin-care products that have a slightly acidic pH to balance the skin’s natural pH level,” says Joshua Zeichner, MD, a board-certified dermatologist. “The outer skin layer, referred to as the acid mantle, has a pH of about 5.5. Harsh scrubs, true soaps, and even hard water can disrupt the outer skin layer, alter the pH, and cause inflammation.” AKA nothing that you want to happen on your complexion.

And so he recommends using a facial toner to combat the issue. “Toners can be helpful if you have hard water to maintain a healthy pH and optimize skin functioning,” says Dr. Zeichner. To make sure your own water isn’t sabotaging your complexion, swipe on one of my fave toners, below.

Skin-restoring toners

Thayers Witch Hazel Toner in Rose Petal $10

Marie Veronique Balancing Hypo Tonic $45

Murad Hydrating Toner $34

Also key for a healthy skin is to include niacinamide in your skin-care regimen for a strong barrier. And here’s how to soothe skin redness, according to dermatologists.