If your hair feels dry, dull, rough, tangly, or like your products are not working, your routine might not be the problem. Water type can make a big difference. In the UK, many homes have hard water or soft water, and water hardness can affect hair health, how shampoo lathers, and how conditioner rinses. If you are searching for “hard water hair” or “soft water hair”, this guide will help you work out what is happening and what to do next. [1]

Across the UK, tap water can be soft, hard, or somewhere in between. Hardness mainly comes from dissolved calcium and magnesium. Those minerals can interact with cleansing and conditioning ingredients, and they can also deposit onto hair over time. [1], [5], [6], [7]

Below, you will find what hard water and soft water mean, how to tell what you have, and simple, realistic changes that can improve hair feel and manage build-up.

What is hard water?

Hard water is water with higher levels of dissolved minerals, mainly calcium and magnesium. Water hardness is often shown as mg/L (milligrams per litre) as calcium carbonate (CaCO₃). It is commonly grouped into bands such as soft, moderately hard, hard, and very hard. [1]

Hard water is safe to drink. It is not “dirty”. It is just more mineral-rich. [1], [3]

What is soft water?

Soft water has lower levels of calcium and magnesium. It usually makes shampoo lather quickly and easily. That can feel amazing. It can also change how products rinse, especially if you use rich conditioners or styling products. [1], [3]

Soft water is not “bad” for hair. It just needs different tweaks.

Why the UK has different water types

UK water type depends on geology and water sources. Rainwater starts soft. As it moves through rock and soil, it can pick up minerals. Areas with chalk and limestone tend to have harder water. Areas that use more surface water (like lochs and reservoirs) often have softer water. [1], [2], [8], [9]

Typical water hardness varies across the UK. Local results can differ street by street. Check your water supplier or postcode checker for your exact water hardness. [1], [2], [4]

 

How hard water can affect hair health

If you live in a hard water area, you might notice one or more of these:

• Hair feels rough, dry, or tangly. [7]

• Hair looks dull, less shiny. [7]

• Shampoo does not lather well. [3]

• Hair feels coated or “waxy” after washing. [7]

• Conditioner feels like it sits on top. [7]

• Blonde, coloured, or chemically treated hair feels harder to manage. [5], [6]

Why this happens

Hard water minerals can interact with surfactants (cleansers) and can contribute to hard water build-up on hair. That build-up can change how hair feels between washes. It can also make it harder for conditioning ingredients to deposit evenly, or for product residue to rinse cleanly. [3], [5], [6], [7]

If you have bleached or coloured hair, you may notice the effects more. More porous hair tends to pick things up more easily. [5], [6]

How soft water can affect hair

If you live in a soft water area, you might notice:

• Shampoo lathers very quickly. [3]

• It is easy to use too much shampoo or conditioner.

• Hair can feel “slippy” in the shower.

• Fine hair can feel heavy or limp if conditioner is too rich.

• Roots can fall flat faster if you over-condition.

Soft water issues are often more about product amount and rinse habits than minerals.

How to tell if you have hard water or soft water

The most accurate option

Check your local water supplier’s water quality report, or use an official postcode checker where available. You are looking for “hardness” and the value (often mg/L as CaCO₃). [1], [2], [4]

Quick signs (not a diagnosis, but helpful)

Hard water signs:

• Limescale in kettle or shower. [3]

• Soap scum. [3]

• Shampoo that struggles to foam. [3]

Soft water signs:

• Lots of lather quickly.

• Products feel like they take longer to rinse.

• Hair can feel weighed down if you use rich formulas.

What to do if you have hard water hair

If you are dealing with hard water hair, the goal is to remove mineral build-up and help products work better. [5], [6], [7]

1) Use a chelating or clarifying wash sometimes

Look for a chelating shampoo or a clarifying cleanser that includes chelating ingredients. At An'du, we haven't (yet) developed one of these, but they do exist and they are out there. Look for INCI labels that include:

• Disodium EDTA / Tetrasodium EDTA
• Citric acid (when used in well-designed formulas)
• Sodium gluconate

Chelation helps bind minerals so they can rinse away. [5], [6]

How often should you clarify for hard water?
Many people do well with every 1 to 4 weeks. Start less often if your hair is dry or very curly. Increase only if you need it.

2) Rinse longer and adjust your wash technique

Small changes help a lot:

• Rinse your hair for longer than you think you need (we always recommend this for shampoo bars anyway!)

• Shampoo twice if you have build-up (first cleanse loosens residue, second cleans).

• Keep conditioner mainly on mid-lengths and ends.

3) Try an optional acidic rinse (gentle and diluted)

A mild acidic rinse can reduce that rough feel for some people.

A simple option:

• Mix 1 tablespoon apple cider vinegar into a mug of water.

• Apply to lengths after shampoo.

• Leave 30 to 60 seconds.

• Rinse out.

Avoid neat vinegar. If your scalp is sensitive, keep it off the scalp.

4) Consider water hardware, but know what it can and cannot do

Many shower filters are aimed at chlorine or general impurities. They may not reduce water hardness minerals unless they are designed for softening (often via ion exchange). A water softener is a more direct fix for hardness. If you rent, routine changes and chelation are usually the easiest place to start. [1], [3]

What to do if you have soft water hair

If you have soft water hair, the goal is usually to prevent over-application and reduce product build-up.

1) Use less product

Soft water lathers fast. You often need less shampoo than you think. The same goes for conditioner.

Try this:

• Use half your usual conditioner.

• Emulsify conditioner in wet hands before applying.

• Apply from ears-down.

2) Clarify occasionally if hair feels coated or limp

Soft water can still lead to build-up from products, especially if you use heavier conditioners, oils, or styling creams.

A gentle clarifying wash every 3 to 6 weeks can help.

3) Choose lighter conditioning if roots collapse quickly

If your hair gets flat fast, it may not be damage. It may be too much conditioning for your hair type and water type combination. Try a lighter conditioner or use less.

Quick routines you can save

Hard water routine (simple weekly template)

• Shampoo

• Shampoo again if you have build-up

• Conditioner on lengths

• Every 2 to 4 weeks: swap your first wash for a chelating or clarifying wash

Soft water routine (simple weekly template)

• Use less shampoo (it will lather)

• Light conditioner on ends

• Every 3 to 6 weeks: gentle clarifying wash if hair feels heavy

When it might not be water

If you have sudden shedding, scalp pain, inflammation, or patchy hair loss, do not assume it is hard water or soft water. Speak to a GP, dermatologist, or a qualified professional, especially if symptoms are new or getting worse.

FAQ 

Does hard water cause hair loss?

Hard water is more linked to hair feel, dryness, tangles, and build-up. If you are seeing sudden shedding or scalp symptoms, it is worth getting medical advice.

What is hard water build-up on hair?

It is a mix of mineral deposits and residue that can make hair feel coated, dull, or rough. It can also make shampoo and conditioner behave differently. [5], [6], [7]

What is the best shampoo for hard water hair?

Many people benefit from an occasional chelating shampoo or clarifying wash, plus a regular cleanser that rinses well. The “best” option depends on your hair type and how hard your water is.

How do I know if my water is hard or soft in the UK?

Check your water supplier’s water quality report or an official postcode checker. Look for water “hardness” and the mg/L CaCO₃ figure. [1], [2], [4]

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References

[1] Drinking Water Inspectorate (England and Wales). Water hardness causes, classification bands, and typical hardness map.
https://www.dwi.gov.uk/consumers/learn-more-about-your-water/water-hardness-hard-water/

[2] Scottish Water. Hardness in drinking water explained (factsheet PDF).
https://www.scottishwater.co.uk/-/media/ScottishWater/Document-Hub/Factsheets-and-Leaflets/Factsheets/250221SW_FactSheet_12_2020V8webPages.pdf

[3] Drinking Water Quality Regulator for Scotland (DWQR). Water hardness FAQ (lather and limescale notes, safety).
https://dwqr.scot/public-water-supply/drinking-water-quality-faqs/water-hardness/

[4] Northern Ireland Water. Water quality results postcode checker (includes hardness).
https://www.niwater.com/about-your-water/drinking-water/water-quality-results

[5] Marsh JM, Wickett RR, et al. “The structural implications of water hardness metal uptake by human hair.” International Journal of Cosmetic Science (2011). Europe PMC record.
https://europepmc.org/article/MED/21923661

[6] Robbins CR, et al. “Uptake of calcium and magnesium by human scalp hair from waters of different locations.” Science of the Total Environment (via ScienceDirect page).
https://www.sciencedirect.com/science/article/pii/S0048969799003253

[7] Kaliyadan F, et al. “Scanning electron microscopy study of hair shaft changes related to hardness of water.” (SEM comparison of hard vs soft water exposure).
https://ijdvl.com/scanning-electron-microscopy-study-of-hair-shaft-changes-related-to-hardness-of-water/

[8] Geological Society. “Hard & Soft Water” factsheet (geology explanation).
https://www.geolsoc.org.uk/~/media/shared/documents/education%20and%20careers/Resources/FactSheets/Water%20Hardness%20Factsheet%20for%20students.pdf?la=en

[9] South West Water. Water hardness factsheet (rainwater starts soft; chalk/limestone increase hardness).
https://www.southwestwater.co.uk/siteassets/documents/factsheets/water-quality-factsheet-water-hardness.pdf