What's actually in your bathroom limescale (and how we get rid of it)

London has the hardest water in the UK. The chalk under the city makes its way into every kettle, every showerhead, every tap, and every toilet bowl, and over time it leaves a chalky, crusty deposit that no amount of normal cleaning will shift. That's limescale.

What it actually is: mostly calcium carbonate, with smaller amounts of magnesium carbonate. The same stuff stalactites are made of. When water sits or evaporates on a surface, the minerals stay behind. Over months and years, they layer. By the time you can see it, there's far more there than you think.

The reason normal cleaners don't work on it: limescale is alkaline. You need an acid to dissolve it. The bottles you buy in Boots — Viakal, Limelite, Cif Bathroom — are mild acids. They work, eventually, on light deposits. On heavy limescale they bounce off.

What we use: stronger acids, applied carefully, with proper protective equipment. We won't tell you exactly what — partly because the products are trade-only, and partly because we don't want clients trying them at home and damaging their bathrooms or themselves.

Limescale is mostly calcium carbonate. The same stuff stalactites are made of.

What you can do, between visits, to slow it down: squeegee the shower screen after every shower (genuinely the single most effective habit in any London bathroom), wipe taps dry after use, and run a kettle descaler through your kettle every fortnight. If you have a power shower and the spray pattern has gone weird, unscrew the head, soak it in white vinegar overnight, and scrub the holes with an old toothbrush. The flow will come back.

For really heavy limescale on a toilet — the kind that's built up below the water line over years — we use a pumice stone, gently. It sounds aggressive but it works on porcelain without scratching, where chemical methods just give up. Don't try it on enamel.

The honest truth about limescale is that in London, it never really goes away. We just stay ahead of it.