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Can hard water damage your hair? What experts say may surprise you

If you have fine, thin or color-treated hair, you might want to give this one a read.
Kara Birnbaum / TODAY

Without a doubt, H2O is an essential part of many aspects of our lives. We need it to keep our bodies hydrated. It's vital to keeping our skin moisturized. And it's definitely a requirement when it comes to cleanliness. But, there's a single caveat when it comes to that last one — we're talking about hair care.

If you're big on beauty (like us), you may have come across the term "hard" water, and not in a very positive way. It's said that it could cause damage to your tresses and affect the way it feels and how you style it. So, we asked two hair experts to help us get the facts straight on this type of water, what it does to the hair and if it's worth avoiding at all costs.

What is hard water? | How does it affect hair? | Does hard water damage hair? | Products to help protect your hair | Meet our experts | How we chose

What is hard water?

According to the International Journal of Preventative Medicine, hard water "is usually defined as water, which contains a high concentration of calcium and magnesium ions." You can read up on a ton of research regarding its impact on drinking water and even some appliances where water is a necessity, but as far as your hair goes, it's not doing you any favors.

How does hard water affect hair?

"The main impact is it really dries the hair out," says board-certified trichologist Penny James. "The cuticle gets a little bit more flared and that's due to sort of the magnesium and calcium compound that's actually made up in the water."

According to master hairstylist Rodger Azadganian, your personal hair texture is also going to determine how your hair feels after a hard water shower.

"If you're an individual that has really fine hair that's dry, then yeah, it's going to affect your hair, without a doubt. Because you're going to soak it up like a sponge," he clarifies. For coarser, medium-to-thick hair, Azadganian says hard water most likely won't cause as much of an issue.

But that's not to say hard water can't produce buildup, which you'll want to avoid with regular washes (preferably with soft water). Azadganian offers a hot take on the subject, saying you should be cleaning your hair more than you probably already do.

"It’s an old wive’s tale that you shouldn't shampoo your hair every single day. You should shampoo your hair every single day, because you’ve got these things called sebaceous glands that secrete the oil on the cuticles of the hair that attracts a lot of particles and dirt. If you don't get that taken off every single day over a period of time, it'll build up on the hair and dry the hair."

Does hard water damage hair?

Do you want the good news first, or the bad news? Let's stop your worries and go with the good: After talking with both our experts, it seems like hard water isn't doing as much damage to your hair as you may have heard or read about.

"The good news is it's not going to damage your scalp," explains James. "[Hard water] is not going to create more problems to the scalp, unless you've got a sensitivity to excess calcium and excess magnesium or the compounds that are used in the softening of water." In this case, James says the hard water could possibly create a certain form of dermatitis on the scalp, meaning you might be a little itchy or irritated. But as far as the rumor of hard water causing hair loss, James says there's no truth behind it.

"Eight out of 10 times, it's not the water that's the issue. It's the individual and the fact that they don't really take proper care of their hair," says Azadganian. For him, it's more important to know your hair, that way you can learn the best way to maintain and nurture it.

While hard water can accentuate frizziness and give you that awful feeling of running your fingers through dry, tangled hair, it turns out, you're more likely weakening your strands via your everyday routine — aka, the bad news.

"The water itself — hard water or soft water — is not the culprit that's going damage your hair," says James. "It's getting too many highlights; it's overusing your blow dryer on a very hot setting; it's using metal in a brush; it's using your curling irons at 400 degrees."

If you're caught in a situation where you can't avoid hard water washes — whether you're traveling and only have what a hotel gives you, or you're unable to change to a filtered shower head — James recommends a few steps to avoid longterm effects.

"The only time [hard water] is going to damage your hair is if you don't hydrate the ends correctly. So, when you know that you’re hair is feeling very tangly, make sure that if you're going to a city that you know has hard water, maybe bring a detangling spray with you. If you don't want to use that much conditioner, put your normal amount in, rinse that out in the shower and then once you jump out of the shower, you can put a decent detangling spray on the mid-lengths to ends to help."

Products to help protect your hair

AquaBliss Revitalizing Shower Filter

What we like
  • Amazon bestseller
  • No-tool install
Something to note
  • Need to replace filter often

Hair type: All | Benefits: Reduces chlorine, pesticides, dirt and odors

The easiest fix to your hard water problems could be as simple as a shower head swap. This No. 1 bestseller is designed to filter out those unwanted, itch-inducing chemicals through a proprietary filtering system. Over 30,000 shoppers have given it a five-star rating, with one of them even calling it "life-changing."

Nexxus Ultralight Smooth Shampoo

What we like
  • Blocks frizz in humidity
  • Sulfate and silicone-free
Something to note
  • May not work for very dry hair

Hair type: Frizzy, dry hair | Benefits: Smooths frizzy hair, tames flyaways and adds shine

This 2023 Shop TODAY Beauty Award winner has received many reviews for its frizz-fighting and hydrating abilities. According to the brand, it's great for all hair types to restore strands and keep them smooth for up to 72 hours.

OGX Extra Strength Argan Oil of Morocco Hair Mask

What we like
  • Notes of citrus and florals
  • Boosts strength and elasticity
Something to note
  • Can make hair oily

Hair type: Damaged, dry hair | Benefits: Adds luster, shine and softness to hair

If you can't avoid hard water or want to treat your hair after realizing you washed your hair with it, Azadganian recommends using a mask for 15 to 20 minutes — and at least once a week if it's a common occurrence. This extra-strength mask is designed to deeply condition and heal hair, while also improving its silkiness and shine.

SheaMoisture Rehydrate & Soften Daily Hydration Conditioner

Hair type: All | Benefits: Hydrating, detangling, frizz control 

If we've learned one thing, it's that hard water can cause our hair to take a hit when it comes to moisture. Fight the dryness with this rehydrating shampoo, which is also designed to soften and detangle strands.

Olaplex No. 6 Bond Smoother

What we like
  • Speeds up blow drying time
  • A little goes a long way
Something to note
  • Can weigh hair down

Hair type: All | Benefits: Strengthens, hydrates, moisturizes 

James says those with over-processed and heavily highlighted hair could benefit from "liberally" using a conditioning treatment. Hair stylists recommend this leave-in conditioner, especially for those with curly and frizz-prone hair, to reduce flyaways and treat damaged hair.

Aussie Total Miracle Sulfate Free Detangler

What we like
  • Fruity scent
  • Conditions and detangles
Something to note
  • Not for all hair types

Hair type: Tangled, dry hair | Benefits: Detangles and smooths knots

The consequence of using hard water for washing your hair could mean post-shower tangles. This sulfate-free detangler is recommended by 100 percent of Target users to gently work through knots and leave hair feeling soft.

Act + Acre Detangling Hair Brush

What we like
  • Prevents breakage
  • Provides scalp massage
Something to note
  • Pricier than other brushes

Hair type: All | Benefits: Detangles

"When you're brushing your hair through, make sure you use a nice brush that's not going to rip the hair," says James. She suggests starting on the ends and in the back of your hair to avoid damage. This brush from Act & Acre is actually designed to avoid breakage, thanks to its double-length bristles. The brand also has a comb that can be used while in the shower to avoid post-shower tangles.

Meet our experts

  • Penny James is a board-certified Tricholigist, IAT, MIT and founder of the Penny James Salon Trichology Center.
  • Rodger Azadganian is a master hairstylist, owner of 8 the Salon and founder of äz Craft Luxury Haircare.

How we chose these products

The Shop TODAY editors and writers search the internet to find the best products out there. We interview expert sources and use our own personal experiences with the product and brand to make shopping easier for our readers.

As an editorial team, we independently create content and determine coverage based on research, reporting and what we think readers would like to read about. The goal of our content is to provide a service and inform readers who are on the hunt for the latest products to help make their life better. Items are sold by retailer, not TODAY. Pricing and availability are accurate as of publish time. Learn more about Shop TODAY.