Tumkur hard water: a practical guide for hair

As water moves through rock it dissolves minerals, principally calcium and magnesium. Groundwater has spent far longer in contact with rock than surface water, so it generally carries more.

Hardness also varies with the season and the depth of the water table, which is why the same household can notice a change through the year without changing anything.

1. 01Check taps, the shower head and the kettle for white scale. Same mineral, visible evidence.
2. 02Soap shake test: a clear bottle a third full of water, a few drops of liquid soap, cap and shake. Little foam and a cloudy scum means hard.
3. 03Note how well shampoo lathers compared with elsewhere.
4. 04Buy hardness strips if you want a number.

• A rough mineral film that dulls hair and makes it feel coated.
• Poor lather, which pushes people to use more shampoo and leave more residue.
• Conditioner that seems ineffective.
• More tangling, and therefore more breakage during combing.
• Faster colour fade and tonal shift on treated hair.
• For some people, a persistent low-grade scalp itch.

1. 01Use a chelating shampoo once, and judge the difference. Look for EDTA or an explicit chelating claim.
2. 02If the change is clear, repeat every week or two.
3. 03Between times, a dilute vinegar rinse, about one part to four parts water, then rinse clear.
4. 04Oil before washing, so hard water meets oil rather than bare cuticle.
5. 05Condition the ends every wash.
6. 06Consider a shower filter, and replace it on schedule.

• Wash more frequently with the same water, which adds deposit.
• Pile on conditioner over an existing film.
• Keep switching shampoo brands, when the water is the variable.
• Assume the hair is permanently damaged before trying one chelating wash.