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Does Hard Water Cause Hair Loss? A Science-Backed Answer
Dr Mir Malkani
Medically reviewed by
Dr Mir Malkani
Updated on December 3, 2024

Do you know if your home is supplied with hard or soft water? Around 60% of the UK uses hard water [1], so there’s a good chance you use it for drinking, washing, cooking, and more. 

Evidence on hard water and hair damage is inconclusive. But does hard water cause hair loss? Research suggests mineral deposits on your hair from hard water may worsen its condition and indirectly contribute to shedding, but it’s unlikely to be the main reason your hair is falling out.  In this article, we’ll explore:

  • What hard water is and if it causes hair loss
  • How else hard water can affect your health and the best hard water hair treatment
  • Other causes of hair loss
Table of Contents

What is hard water?

Hard water contains a high concentration of calcium and magnesium ions. There are several other dissolved metal ions that cause water hardness, including aluminium, barium, strontium ions, zinc, and manganese [2]. However, levels of these ions in drinking water are barely noticeable, and may be elevated only in certain geographic areas with deposits of these specific minerals.

Most of the water in the South East and East of the UK is hard, while most of the North, West, and South West has soft water [3]. Water hardness is measured in milligrams of calcium carbonate per litre (mg/l CaCO3) or parts-per-million (ppm). This table shows what counts as hard water vs. soft water [4].

 

Water Hardness (mg/l CaCO3)

Soft

up to 100

Slightly hard

100 – 150

Moderately hard

150 – 200

Hard

200 – 300

Very hard

More than 300

Does hard water cause hair loss? 

Research behind hard water and hair loss is contradictory. Some research indicates hard water may cause hair loss due to damage and hair breakage [5], but other studies suggest otherwise [6]. However, even if hard water is contributing to your hair loss, it’s unlikely to be the main factor. 

Is hard water bad for your hair? 

Here’s a breakdown of the research on hard water, hair damage, and hair loss: 

  • One study found hard water reduces hair strength and increases breakage [5]
  • Another study based in Pakistan linked hard water to reduced hair strength [7]
  • A 2013 study found no difference between hair strength or elasticity in people who use hard versus soft water [6]. However, this only included 15 participants, compared to 70 and 76 in the studies that found the opposite. It also studied results over just 30 days and conceded that longer studies may have different results — research that found the opposite ran over 3 months.   
  • Using hard water could lead to mineral deposits (particularly magnesium) on your hair’s surface. But this doesn’t necessarily cause visible damage to your hair when it’s put under a microscope [8]
  • People with higher levels of mineral deposits on their hair perceived their hair health as worse than people with lower metal levels [9]

From these findings, we can conclude that hard water likely has some negative effects on hair health. However, these may not be visible until you’ve used hard water for several months. 

is hard water bad for your hair

Dr. Patrick Angelos, the author of The Science and Art of Hair Restoration, believes that hair loss can be caused by hard water. He says it can occur when the scalp is severely affected by hard water but adds that this is more common in people with psoriasis or eczema [10].

  1. A 2018 study found that hair samples treated with hard water had lower tensile strength than those treated with deionised (soft) water. The average tensile strength was 234.16 N/mm² for hair treated with hard water, compared to 254.84 N/mm² for hair treated with deionised water. 70 male participants, aged 20-30, were included. All had straight hair which was at least 24 cm long [5].
  2. A 2013 study compared the strength and elasticity of hair washed in hard water vs. distilled water. There were 15 participants. Hair samples were treated in hard and soft water for 10 minutes every other day, for 30 days. Average strength and elasticity were similar for the hard and distilled water groups. There was no significant difference in hair strength or elasticity between the two types of water [6].
  3. Scanning electron microscopy (SEM) was used to identify differences between hair shaft samples from normal, healthy volunteers treated with hard or soft water. Imaging revealed that hard water can lead to increased mineral deposits, particularly magnesium, on the hair’s surface. These deposits didn’t correlate with visible damage on the hair’s surface [8].
  4. Researchers studied hair from over 300 people in 9 countries. Even within the same area, a wide range of metal levels were found on the hair’s surface. Calcium, magnesium, and copper increased from root to tip, which showed that daily environmental contact affected hair. People who used hair dye had higher levels of metals linked to hard water. People with higher mineral deposition generally felt their hair was in poor condition [9].

Hard water can also dry out your hair and make it more difficult to rinse out shampoo and conditioner [11]. This can make your hair look dull and difficult to brush, causing an itchy scalp.

Minerals in hard water can combine with shampoo ingredients to form a residue that clings to your hair and scalp. This can make your hair feel dull, heavy, or unclean even after washing.

These minerals also react with the surfactants in shampoo, reducing their ability to lather and cleanse effectively. This may lead to build up of dirt in your hair. To compensate for this effect, many people use more shampoo. This can further increase the deposition of shampoo-originating residues, and may also strip natural oils from your hair. 

To combat this, there are special shampoos for hard water (chelating shampoos). Alternatively, water for washing your hair can be treated with water softeners which reduce the water’s mineral content.

Tangles and knots can form in your hair when you wash it with hard water. This can cause shampoo to remain stuck on your hair, and may cause a buildup on your scalp [11].

The effects of hard water appear to be worse when combined with frequent hair treatments. This combination could lead to dandruff, an itchy head, and dry skin on your scalp [11]. In addition, people with psoriasis and eczema on the scalp may find their conditions worse when they use hard water [11]. This may indirectly affect hair loss.

is hard water good for you

How do I protect my hair from hard water?

To protect your hair from hard water, try using a showerhead filter to reduce the level of dissolved minerals. To minimise further damage, you can also try air drying your hair, avoiding excessive heat damage from styling, and using a heat protection spray.

Can drinking more water reverse hair loss?

Drinking more water could possibly help with hair loss if you’re chronically dehydrated. There may be a link between dehydration and hair loss due to its effects on oxidative stress, blood flow, and scalp health. 

What does hard water damage to hair look like?

A buildup of minerals on your hair from hard water may cause it to look dry, brittle and more frizzy. It may also lack shine, appear duller, and become tangled easily. 

Is hard water damage reversible?

While the jury’s still out on whether hard water damages your hair, it’s definitely possible to reverse dry, brittle hair. If you believe your water supply is damaging your tresses, try filtering your water. Invest in natural hair products, use leave-in conditioners, and speak to a trichologist if your hair condition doesn’t improve. 

causes of hair loss

Other potential causes of hair loss 

If you’re experiencing hair loss, hard water isn’t likely to be the main culprit. Here are some other reasons your hair might be falling out.

trichology tests for hair loss

Treating hair loss at the Wimpole Clinic

Noticed more hair loss in the shower than normal? While it’s possible hard water could be linked to hair loss, it’s not the most likely reason your hair is falling out.

To learn the source of your symptoms and stop further hair shedding, speak to a trichologist. These hair doctors can offer a comprehensive assessment, including determining the impact of hard water and other factors on your hair through diagnostic trichology tests (such as blood tests for hair loss or a hair pull test).

Once you have a diagnosis, they can recommend the best research-backed treatment for you. This may include PRP hair treatment, low-level laser therapy, or even a natural-looking hair transplant. Book a consultation at your nearest clinic location to get your hair back on track.

Does Hard Water Cause Hair Loss? A Science-Backed Answer, Wimpole Clinic

FAQs

Hair health isn’t the only factor that could be affected by hard water. Research suggests mineral ions in the water may affect your health in other ways. 

However, research on this topic is split. Some studies indicate hard water may be bad for your health, while others suggest it might be beneficial and protect against some medical conditions. Research on cardiovascular health and hard water is particularly contradictory. 

Some studies and health experts advise that hard water is good for your health. Delegates at a WHO meeting in 2008 advised that hard water may protect against cardiovascular disease due to its calcium and magnesium content [18]. However, they acknowledged that research in this area is contradictory and further studies are needed. 

Calcium and magnesium in hard water may improve your health by contributing to your dietary mineral intake [19]. Hard water may also have protective effects against [20]: 

  • Cardiovascular disease
  • Some cancers
  • Cerebrovascular disease
  • Diabetes
  • Pre-eclampsia
  • Constipation
  • Low bone mineral density 

On the other hand, some research says the opposite. Studies found links between hard water and increased risks for heart disease, reproductive issues and other health problems. Researchers believe this is likely due to magnesium and calcium in the water [21]. 

Hard water can change the pH balance of your skin, which may negatively impact skin health. It reduces the protective effect of your skin against bacteria and infections, which can worsen skin conditions like eczema and psoriasis [22]. 

A literature review also suggests there may be a link between hard water and an increased risk for several health conditions. These include [20]: 

  • Impaired foetal development
  • Alzheimer’s disease (due to increased aluminium content in hard water)
  • Eczema 
  • Kidney stones
  • Impaired male reproductive health
Dr Mir Malkani
Medically reviewed by Dr Mir MalkaniUpdated on December 3, 2024
The Wimpole Clinic offers FUE Hair, Beard & Eyebrow Transplants & Trichology.
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