If your kettle has a crust in it, your hair is drinking the same water.

Hard water is mineral-heavy water — mostly calcium and magnesium — and the South East of England is the recognised bad patch. Ireland is not uniformly soft either, whatever people tell you: North Dublin is hard, South Dublin is on a different supply and much softer, and Clare sits on solid limestone, so it is hard as anything.

What the minerals do is deposit. Every wash leaves a very thin film on the hair that builds up over weeks. The effect is oddly specific and women describe it the same way independently: hair that is flat and frizzy at the same time, dull no matter what you use, and that will not hold a curl or a blow-dry the way it used to. One woman who had just moved to Dublin put it plainly — the hard water was killing her hair and it would not hold its curl pattern any more.

The frustrating part is that the build-up sits between the product and the hair. You can buy something excellent and get very little from it, because it never makes contact. That is the single most common reason a good treatment underperforms, and it has nothing to do with the treatment.

Two things help. A shower filter is cheap, renter-friendly and worth the twenty quid. And a twice-weekly treatment that is properly rinsed through does the other half of the job — women already use the phrase "metal detox" for this, which is a decent description of what you are after.

You are not imagining it, and your hair is not being dramatic. Your water is.