How to Get Rid of Limescale Without Buying Anything Special

Limescale is calcium carbonate left behind when hard water evaporates. Any acid dissolves it. This is not a difficult chemistry problem, which is why the price range of products that do it is so absurd.

We tested four options on identical scaled shower screens and kettle elements: a branded bathroom descaler, white vinegar, citric acid powder dissolved in warm water, and lemon juice.

The results

Citric acid won. A tablespoon in 250ml of warm water removed heavy kettle scale in twenty minutes and shower scale in about forty. It has no smell, which is its main advantage over vinegar.

White vinegar performed almost identically, marginally slower on the heaviest deposits. It costs slightly less. The smell dissipates within an hour of rinsing but is genuinely unpleasant during.

The branded product worked at about the same speed as vinegar and cost roughly eleven times as much per application. It smelled better and clung to vertical surfaces more effectively, which is a real advantage on a shower screen.

Lemon juice was the weakest. It works, but it is a dilute acid with sugars in it, and on anything textured it leaves a sticky film you then have to clean off.

The technique that actually changes results

Acid needs time and it needs to stay put. Spraying a vertical surface and wiping after two minutes achieves almost nothing, because the liquid runs off within seconds.

1. Warm the surface or the solution. Warm acid works considerably faster than cold. For a kettle, fill it, boil it, then switch off and leave. For a shower, run the hot water for a minute first.
2. Hold it in contact. On vertical glass, soak paper towel in the solution and press it flat against the scale. On taps, fill a sandwich bag with solution and tie it around the spout with an elastic band.
3. Wait properly. Twenty minutes minimum, an hour for heavy build-up. Set a timer and leave the room — the temptation to check and wipe defeats the whole method.
4. Agitate, do not scrub. After soaking, the scale has softened. A plastic scourer or an old toothbrush removes it. Wire wool and abrasive creams scratch chrome and glass permanently.
5. Rinse thoroughly. Any residue left on metal will keep working slowly, and on some finishes that causes dulling.

Where else this applies

• Kettles — fill to the element, add two tablespoons of citric acid, boil, leave twenty minutes, rinse three times.
• Shower heads — unscrew and submerge overnight in a bowl. Far more effective than the bag method.
• Toilets — the waterline ring is limescale. Pour a litre of vinegar in, leave overnight, brush in the morning.
• Dishwashers and washing machines — run empty on the hottest cycle with 100g of citric acid in the drum.

Preventing it instead

Scale forms where water sits and evaporates. A squeegee on the shower screen after each use, taking fifteen seconds, prevents essentially all of it. It is dull advice, but no cleaning product will ever beat not letting it form.

If you live somewhere genuinely hard, a scale inhibitor on the mains supply is worth costing out. It will not remove existing scale but it substantially slows new deposits, and it protects the boiler, which is the expensive part nobody sees.