
Put tersely, hard water damages hair.
Hard water has a large quantity of calcium, magnesium, iron and copper. It’s this high concentration of minerals that damages hair.[i]
Washing hair in hard water causes it to become/feel straw-like, dry and brittle; it’s likely that your hair will break or start thinning because the hair follicles become blocked thereby preventing the flow of nutrients to the scalp. Your scalp may also become dry and flaky.
Click one of the maps to see if you live in an area with hard water.

- Install a showerhead with a water filter. These filters enhance the pH balance of water and remove unwanted chemicals from it. You don't even have to replace the whole showerhead, I just got a filter that fits onto my existing shower head. See highly rated shower heads with water filters from Amazon below. But beware! The shower filter made my scalp itch!
- Try apple cider vinegar. Apple cider vinegar clears hair of minerals and gives it some shine. I would add a cup of apple cider vinegar to three litres of water and use that to rinse conditioner out of your hair. Apple cider vinegar has a pH between 4.25 and 5.00. Healthy hair has a pH between 4.50 and 5.00. I recommend you test the pH of your apple cider vinegar and only use it if it’s above 4.50.
- Try bottled water. I know at least one person that has resorted to buying water to wash their hair! Although this seems drastic, I would say it’s worth it if you’re visiting an area with hard water for a short period of time.
4. Add the juice of a lemon to water. Squeezing lemon juice into water can help to reduce the water's hardness. However, note that the pH of lemon juice is 2, i.e., it’s very acidic so you should dilute it in water (pH = 7) to reduce its acidity before applying it to hair. Healthy hair has a pH of 4.0 to 5.5.

These devices allegedly reduce lime scale; they are fitted to a pipe in the house and are reputed to benefit not only your hair but also other appliances whose function can be reduced by limescale, e.g. the central heating system, boiler and dishwasher.
However, although some argue that they work, the US Navy did a series of tests to check the effectiveness of ‘magnetic’ and ‘electric’ water softeners. They concluded that they have no effect at all. It appears that although the limescale is removed from water that come out the tap, that limescales stays in the pipes ultimately leading to problems with the heating system. “Magnetic lime scale reducers are a plumber's dream,” according to one Amazon product reviewer.
How about chelating shampoos?
Chelating shampoos prevent and remove mineral build-up but they strip hair of all the good stuff too so I personally wouldn’t recommend them. Even on Caucasian hair, a chelating shampoo should not be used more than once a week.
[i] How to Prevent Hair Build-up from Water

Highly rated shower heads with water filters:
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