Expert Insight
Dr Sonia Khorana is a UK-based GP with a special interest in dermatology, known for her evidence-based, practical approach. She treats a wide range of skin and scalp concerns and highlights water as an often-overlooked trigger in everyday routines.

“My patients rarely think of water when their skin flares up, but they should.”

Hard water is rich in calcium and magnesium. These minerals leave a residue on your skin that raises its pH, making it more alkaline. Over time, this can lead to dryness, tightness, irritation, and increase the risk of eczema.

Dr. Sonia Interview on Hard Water Impact (2025)

“Hard water changes how your products work.”

Minerals like calcium and magnesium react with cleansers to create soap scum, leaving a filmy residue on skin, scalp, and surfaces. This buildup blocks moisture and makes products less effective over time.

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“Chlorine accelerates moisture loss, leaving skin feeling tight.”

For sensitive or eczema-prone skin, this irritation compounds over time, making flare-ups more frequent and recovery slower.

“Heavy metals in water are invisible but impactful.”

Trace metals like copper and iron, often found in older pipes, can deposit on skin and scalp. These invisible particles contribute to oxidative stress and interfere with how your skincare and haircare perform. This build-up can explain why some skin feels persistently dry, congested, or irritated even with a consistent routine.

Dr. Sonia Interview on Hard Water Impact (2025)

Ask Dr. Sonia

Hard water can contain minerals, mainly calcium and magnesium, and sometimes trace metals like iron or copper. When water contains such minerals, it doesn’t properly dissolve soap, meaning that there can be some residue left on the skin. This can contribute to sensitive, irritable and blemish-prone skin.

Hard water can also increase skin pH, making it more alkaline. The skin barrier functions best at a slightly acidic pH (~5.5). A higher pH weakens the skin's defence mechanisms.

Prolonged exposure to hard water can result in a compromised skin barrier, making it more susceptible to various skin issues. This can result in a flare up of eczema and psoriasis and even result in heightened skin sensitivity.

Yes, definitely. Where people live, especially the hardness of their water, can make a noticeable difference in their skin health. People living in areas with hard water often have drier, rougher skin, more issues with eczema, and sometimes even a general feeling of tightness after washing and may complain of more sensitivity.

Yes. An observational study done by King’s College London found that high levels of water hardness in the home may be linked to the development of eczema early in life. Previous studies in the UK, Spain and Japan have shown associations between domestic water hardness and the risk of eczema in schoolchildren.

The latest study, published in the Journal of Allergy and Clinical Immunology, examined the link between water hardness and chlorine concentrations in household water, damage to the skin’s natural barrier and eczema in infancy. Living in a hard water area was associated with an up to 87% increased risk of eczema at three months of age, independent of domestic water chlorine content.

Dermatology organisations like the AAD (American Academy of Dermatology) and BAD (British Association of Dermatologists) acknowledge that hard water may worsen or contribute to eczema.

Repeated exposure to hard water minerals and chlorine can affect the skin barrier over time, this makes the skin less able to retain moisture and affected more by irritants, allergens, and microbes. This can lead to chronically dry, rough, or inflamed skin, even if someone didn’t have major issues before. Hard water exposure has been linked to a higher risk of developing eczema (especially if exposure starts early in life).

  • Opt for sulphate-free cleansers
  • Have short, lukewarm showers (under 10 mins)
  • Moisturise immediately after showering to lock in hydration — skin is more absorbent when damp
  • For sensitive skin types, use fragrance-free cleansers and lotions
  • Manage stress. It can be a huge trigger for both eczema and psoriasis flares
  • Use humidifiers in dry environments
  • Choose cotton clothing

Filtering water, especially for the shower, is definitely becoming a popular and dermatology-approved strategy for sensitive skin, eczema, and dryness. It helps to remove chlorine, reduce heavy metals.

Patients have noticed:

  • Less dryness and tightness after showers
  • Reduced itching
  • Fewer flare-ups of eczema/psoriasis
  • Scalp benefits. Less dryness, flaking, and sometimes better hair texture
  • It’s a low-risk, supportive strategy that fits perfectly with a barrier protection approach.

Here are a few reasons why I think water quality gets overlooked in skin health conversations:

  • Most people don't realise that there are minerals, chlorine and metals in water that can quietly and slowly affect the skin barrier over time.
  • Most people also don't know their tap water is hard or highly chlorinated unless they specifically test it.
  • People also don’t realise that environmental triggers like water quality matter. They focus more on skincare products than environments.
  • Hard water or chlorinated water damage usually shows up slowly over time. Sometimes people may not connect skin issues to water quality.

Long-haul travel already dehydrates skin due to cabin pressure and low humidity. When you add chlorine in the mix before or after flying, you’re left with tight, itchy, reactive skin that struggles to retain moisture. Filtering your water is one of the simplest things you can do to protect your skin and hair when you travel. It’s a low-effort, high-impact switch, especially in areas with high chlorine levels or if you spend time in pools. Combined with products that neutralise chlorine, you’re giving your skin a real chance to recover.

Chlorine is a skin irritant that strips natural oils, disrupts the barrier, and accelerates trans-epidermal water loss. It can affect the skin’s pH, which makes it more susceptible to irritation and disruption of the skin microbiome. It also damages hair structure, making it more porous, more brittle, and more likely to fade, especially after colour treatments. Combined with heat, UV, and flights, it’s the perfect storm for barrier breakdown.

Heat accelerates water loss from skin (TEWL), and when combined with chlorine’s drying effects, it can cause intense dehydration and flakiness. Chlorine strips away protective oils, making skin more vulnerable to inflammation, and combined with oxidative stress from UV rays accelerates photo-ageing. Sweat, sunscreen, and sebum can mix with chlorine and other pool chemicals which can potentially clog pores and lead to breakouts or sensitivity.

A high-quality shower filter, like those from Hello Klean, offers a simple but highly effective solution. It removes chlorine, heavy metals and hard water minerals that strip the skin and hair, helps rebalance the skin’s pH and reduces inflammation and flareups, and preserves the natural lipid barrier.

Dermatologist approved solution to reduce chlorine, reduce heavy metals, and impurities.